EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: mrpackethead on January 20, 2015, 09:59:23 am
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While everyone is converting toasters for DIY reflow, this guy
http://bubble.wservices.ch/index.php/DIY_Vapor_Phase_Reflow (http://bubble.wservices.ch/index.php/DIY_Vapor_Phase_Reflow)
converted a deep fryer to do vapour phase soldering. That sir i thought was very clever, in deed. Mechanically this would be really the easiest conversion that you could imagine.
I'm curious however , how you handled double sided componentry?
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Call me a noob....but how does this work? Then I hear vapor, I assume a phase change - like liquid to gas.
If this is just re-flowing a board in deep-fryer, that's not that interesting.
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This is from memory, so it could be completely wrong :P
You have a special (and expensive, usually fluorine based) fluid which has a boiling point above soldering temperature. You turn it into a gas with heat, and then it condenses on things that are colder than the gas (aka your PCB) and heat it up slowly. Thus you will eventually transfer all of the heat into the PCB and the solder will melt. The interesting thing is that the heating is slower than IR and the vapour will spread under things like BGAs etc so you are supposed to get much better yields for less tuning.
Also, from looking at this page he hasn't actually done anything yet? other than select a deep fryer.
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Vapour phase is close to the "ideal" reflow soldering method, as the temperature is consistent and defined by the boiling point of the fluid. You don't need to worry about overheating or board profiling.
One reason it's not common in industry it's hard to integrate into a continuous production line - it's usually used as a batch process, particularly for heat-sensitive components.
However the problem is that the fluid is expensive, and hard to buy in small quantities.
For double-sided, most parts will stay on due to surface tension of the solder. Larger parts may need glue dots
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The other problem is there is only one manufacturer - Galden
AU$1850 for 5kg :
http://www.oritech.com.au/productDetail.aspx?productID=40254 (http://www.oritech.com.au/productDetail.aspx?productID=40254)
Here's someone that sells small quantities :
http://www.electronic-thingks.de/en/electronic-products/soldering-accessory/galden-ls-230.html (http://www.electronic-thingks.de/en/electronic-products/soldering-accessory/galden-ls-230.html)
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Mike: how much do you think you would need for a little board? Say 5cm x 10cm single sided load with surface mount only. I wonder if you could get away with 100ml or so...
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Anyone knows if those liquids are dielectric?
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One reason it's not common in industry it's hard to integrate into a continuous production line - it's usually used as a batch process, particularly for heat-sensitive components.
In the early days of surface mount PCBs vapour phase was the only technique used. I thought it was making a comeback with the higher temperatures now required, and the energy savings which are possible,
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Previous discussions on trying to find a source of the fluid:
https://www.eevblog.com/forum/projects/heat-transfer-fluid-distributors-in-europe/ (https://www.eevblog.com/forum/projects/heat-transfer-fluid-distributors-in-europe/)
https://www.eevblog.com/forum/reviews/professional-grade-reflow-ovens/30/ (https://www.eevblog.com/forum/reviews/professional-grade-reflow-ovens/30/)
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Mike: how much do you think you would need for a little board? Say 5cm x 10cm single sided load with surface mount only. I wonder if you could get away with 100ml or so...
No idea - would depend on the size/shape of the tank and how well you can prevent losses.
Vapour phase kit tends to use a cooling coil at the top to reduce losses.
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Call me a noob....but how does this work? Then I hear vapor, I assume a phase change - like liquid to gas.
If this is just re-flowing a board in deep-fryer, that's not that interesting.
It is reflowing, but its as you worked out the heat is transferred to the solder when the board is submerged into a hot vapour. the vapour consdenses on the board ( changes from gas --> liquid ) and at the phase change transfers its heat.
The professional systems start at about $15,000, but the results are really good.
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For double-sided, most parts will stay on due to surface tension of the solder. Larger parts may need glue dots
Thats what i'd assumed, much like what happens with more traditional reflow. Probably just need to arrange to ensure that the previously soldered side is sitting on a stand off etc.
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The other problem is there is only one manufacturer - Galden
AU$1850 for 5kg :
http://www.oritech.com.au/productDetail.aspx?productID=40254 (http://www.oritech.com.au/productDetail.aspx?productID=40254)
Here's someone that sells small quantities :
http://www.electronic-thingks.de/en/electronic-products/soldering-accessory/galden-ls-230.html (http://www.electronic-thingks.de/en/electronic-products/soldering-accessory/galden-ls-230.html)
Can source it for USD$850 for 7kg ( ~3.8l / 1 gallon ),
If you are careful you should not be loosing it out the top so, its good for many cycles.
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The concept of using a a deep fryer was really quite clever, almost every thing you need is there. Just need to add a cooling frame work to it. I'd probably use some alluminum heat sink profile and maybe stick some pelters on it to keep it nice and cold.
Its looks and feels like a nice tinker project!
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The other problem is there is only one manufacturer - Galden
AU$1850 for 5kg :
http://www.oritech.com.au/productDetail.aspx?productID=40254 (http://www.oritech.com.au/productDetail.aspx?productID=40254)
Here's someone that sells small quantities :
http://www.electronic-thingks.de/en/electronic-products/soldering-accessory/galden-ls-230.html (http://www.electronic-thingks.de/en/electronic-products/soldering-accessory/galden-ls-230.html)
Can source it for USD$850 for 7kg ( ~3.8l / 1 gallon ),
If you are careful you should not be loosing it out the top so, its good for many cycles.
Care to share your source? I'm interested.
I've been digging through patents and stuff this afternoon. It goes by the name Galden (as Mike mentioned), fluorinert by 3M or Kytox by DuPont. It seems you can get it from some Chinese suppliers, but I don't really trust those links. You can get different versions with different boiling points, but they all have the same CAS number. So I guess its just a more refined form for the higher temps? I can't find fluorinert or Kytox that goes over 215C though, Galden goes up to 260C if you buy the right kind.
Usage in a commercial but benchtop batch oven made by IBL is rated 1g/cycle. Full reflow cycle is 6 minutes. I asked for a quote from their Australian distributor, but given the patents I found by IBL I'm sure it's not going to be cheap ;)
I'm no chemist, but the family of chemicals it belongs to is known as perfluorinated polyethers (PFPE). If you search google for perfluorinated polyether oils you will get lots of hits. It's used as a high/low temperature lubricant by the looks of it.
An interesting patent: http://www.google.com/patents/US4871109 (http://www.google.com/patents/US4871109)
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Im sorry, its US$875.50. not $850.00 but close.
http://store.tmcindustries.com/Galden-HT-230-7-Kg-Bottle_p_229.html (http://store.tmcindustries.com/Galden-HT-230-7-Kg-Bottle_p_229.html)
"Galden® HT is a line of dielectric fluids with boiling points ranging from 55° C to 270° C. The excellent dielectric properties of these perfluorinated polyethers (PFPE) and their high chemical stability combined with the capacity to operate at very low as well as elevated temperatures, make them the best heat transfer fluids for the aggressive conditions found in semiconductor, electronic, and solar industries."
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Interesting, it's not LS230 but HT230. Both have the same CAS numbers and structural formulae. Anyone know a chemist who can shed some light on this?
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Interesting, it's not LS230 but HT230. Both have the same CAS numbers and structural formulae. Anyone know a chemist who can shed some light on this?
It does appear there are some physical characteristics between the two that are different. Cut and paste so can compare the two from
http://www.solvayplastics.com/sites/solvayplastics/EN/specialty_polymers/Fluorinated_Fluids/Pages/Galden-PFPE.aspx (http://www.solvayplastics.com/sites/solvayplastics/EN/specialty_polymers/Fluorinated_Fluids/Pages/Galden-PFPE.aspx)
Watch out some of the units are not the same. the big one that stood out to me, was the vapour pressure is vastly different.
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Anyone knows if those liquids are dielectric?
no isolation of the wires here: http://www.ibrtses.com/projects/vapourphasesoldering.html (http://www.ibrtses.com/projects/vapourphasesoldering.html)
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Anyone knows if those liquids are dielectric?
no isolation of the wires here: http://www.ibrtses.com/projects/vapourphasesoldering.html (http://www.ibrtses.com/projects/vapourphasesoldering.html)
It is a dielectric.
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Ok, I'm very interested. Anyone up for a group buy?
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The necessary quantity of liquid can be minimized if the bottom side of the pot is narrow. The heater could be immersed in the fluid in that end. As the beaker wides, the PCB size can be bigger.
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I'm curious about the post-processing steps. How much of the working fluid winds up on the board by the end of the process? Presumably at that price point you want to recover every drop from the finished board! If a rinse is required , is it as simple as rinsing with distilled water or alcohol, then using a low heat cycle to boil off the rinse and recover the working fluid?
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Main problem with vapour phase is tombstoning due to an imbalance of thermal properties of the design.
This is assisted by slightly more inert atmosphere in the vapour cloud compared to IR/ convection oven.
I am presently looking at a new USD6000 vapour phase unit versus a laser soldering robot for those pesky double sided jobs.
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Main problem with vapour phase is tombstoning due to an imbalance of thermal properties of the design.
This is assisted by slightly more inert atmosphere in the vapour cloud compared to IR/ convection oven.
I am presently looking at a new USD6000 vapour phase unit versus a laser soldering robot for those pesky double sided jobs.
According to this guy: http://www.kemet.com/Lists/TechnicalArticles/Attachments/28/f2102a.pdf (http://www.kemet.com/Lists/TechnicalArticles/Attachments/28/f2102a.pdf) tombstoning can be minimised by proper preheating.
If you do end up buying one, please sell me some galden! ;D
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Why wouldn't one just use a hot air convection oven?
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Why wouldn't one just use a hot air convection oven?
When one BGA is worth $50, you don't have to make many toaster oven mistakes to cover the cost of the fluid :P
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I'm not necessarily talking about home brew solutions, though it might apply here too.
If we are trying to solve the problem of uneven heating due to radiant paths, then a circulating hot fluid can help. But why does the hot fluid need to be some expensive chemical? If you circulate hot air around the board it seems you should get even heating in a similar manner at lower cost.
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I'm not necessarily talking about home brew solutions, though it might apply here too.
If we are trying to solve the problem of uneven heating due to radiant paths, then a circulating hot fluid can help. But why does the hot fluid need to be some expensive chemical? If you circulate hot air around the board it seems you should get even heating in a similar manner at lower cost.
You won't get even heating with hot air. The main "thing" in this fluid is boiling temperature, it will condense at coldest parts (read heat them most), therefore even heating is guaranteed. Also you cannot overheat the parts.
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I'm not necessarily talking about home brew solutions, though it might apply here too.
If we are trying to solve the problem of uneven heating due to radiant paths, then a circulating hot fluid can help. But why does the hot fluid need to be some expensive chemical? If you circulate hot air around the board it seems you should get even heating in a similar manner at lower cost.
The difference is latent heat of vaporisation.
The heater vaporises the liquid at its boiling point. Additional energy just turns more liquid to vapour without significantly increasing the temperature of the vapour. When vapour condenses on the PCB, it transfers heat efficiently, and will keep condensing as long as the PCB temp is below the vapour temp.
With air, there is no inherent control of temperature, and this will vary significantly due to convection etc. And you will need to start with air at a higher temp to compensate for this to get the temp you want at the surface, and this will vary with different PCBs
It also helps to be using an atmosphere that's chemically inert to avoid oxidation - this is why some conventional reflow setups use nitrogen, especially for higher temp leadfree prcesses.
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(http://www.renesas.com/media/prod/package/manual/block_1_06.jpg)
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Main problem with vapour phase is tombstoning due to an imbalance of thermal properties of the design.
This is assisted by slightly more inert atmosphere in the vapour cloud compared to IR/ convection oven.
I am presently looking at a new USD6000 vapour phase unit versus a laser soldering robot for those pesky double sided jobs.
What machine is $6k, i'm curious. A Laser won't do a BGA very well though.
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Granted that the condensing inert vapour might be the "best" solution, but in other circumstances ordinary forced convection ovens are found to provide more even heating than radiant heating or natural convection. So I am wondering if a fan convection oven using temperature controlled hot air might be a less expensive and less complex compromise?
Sometimes the best can be the enemy of the good...
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Granted that the condensing inert vapour might be the "best" solution, but in other circumstances ordinary forced convection ovens are found to provide more even heating than radiant heating or natural convection. So I am wondering if a fan convection oven using temperature controlled hot air might be a less expensive and less complex compromise?
Sometimes the best can be the enemy of the good...
Yup, but thats going off topic.
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Granted that the condensing inert vapour might be the "best" solution, but in other circumstances ordinary forced convection ovens are found to provide more even heating than radiant heating or natural convection. So I am wondering if a fan convection oven using temperature controlled hot air might be a less expensive and less complex compromise?
Sometimes the best can be the enemy of the good...
I disagree that it is more complex. As you can see from the various links in the thread, all you need is a big test tube, an electric kettle and a variac. No PID, nothing. The only problem is the cost of Galden.
I am of course talking about homebrew style though.
Also, I just got a quote back for the IBL minilab. > $25k with no Galden included :(
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Jeremy,
Thats a Hawker Richardson price.
I have been quoted USD6K plus freight and importation.
Again fluid free price.
I am considering laser soldering robot for those pesky double sided boards.
Dont need much more than a 10W laser.
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Jeremy,
Thats a Hawker Richardson price.
I have been quoted USD6K plus freight and importation.
Again fluid free price.
I am considering laser soldering robot for those pesky double sided boards.
Dont need much more than a 10W laser.
Can you share your source?
Also, 10W at what wavelength? I can't imagine it will be a gas laser because that will just be reflected, so you'll probably still pay a pretty penny for the source itself.
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It just never ceases to amaze me how companies down here think that they can add redicouly large amounts of margins to things like PNP, and other equipment. they seem to think that we don't read the internet..
Is the 6k for the IDL Minilab.
Am getting The Galden LS230 priced up now out of Singapore.
at 6k, DIY might not be worth it.
Jeremy,
Thats a Hawker Richardson price.
I have been quoted USD6K plus freight and importation.
Again fluid free price.
I am considering laser soldering robot for those pesky double sided boards.
Dont need much more than a 10W laser.
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I found this video demonstrating vapor phase soldering:
CPU Soldering (https://www.youtube.com/watch?v=kUVtvfsaZbY#ws)
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I found this video demonstrating vapor phase soldering:
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Very interesting. According to this (http://www.smartgroupsa.org/files/lead-free-reflow-bob-willis.pdf), that is a prototype "oven" from multicore in the early 90s. It's still kicking I guess!
And that guy appears to work for 3M, hence the fluorinert instead of galden.
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If you are wanting to recycle the fluid ( it would be good at the price) You will need to ensure that the top cold zone is as cold as possible, preferably higher than the deep fryer, and with a good source of cooling. A water jacket with a pump to circulate the water and a chiller to make it cold will work best, using an old draught chiller as the cold water source. You need to keep the board in this zone for a while after reflow, to ensure that all the liquid condenses on it and then drips down into the bottom, and keep it running after you turn the heat off till it is at room temperature and you want to dispense it back into a sealable pressure vessel to store it.
Had that where I used to work, though there it was an ultrasonic cleaner using TCE, and it used the vapour phase to clean the fluid, as you could collect the drip off condensed liquid into a bucket and concentrate the dirty fluid down to a sludge for dirt removal. That would take the dirtiest castings you could find and leave them as bare clean white castings. Would strip a PCB of the resin ( except for the one conformal coat that survived no matter what) and all printed and painted parts except the copper and solder in around 3 minutes.
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If you are wanting to recycle the fluid ( it would be good at the price) You will need to ensure that the top cold zone is as cold as possible, preferably higher than the deep fryer, and with a good source of cooling. A water jacket with a pump to circulate the water and a chiller to make it cold will work best, using an old draught chiller as the cold water source. You need to keep the board in this zone for a while after reflow, to ensure that all the liquid condenses on it and then drips down into the bottom, and keep it running after you turn the heat off till it is at room temperature and you want to dispense it back into a sealable pressure vessel to store it.
Had that where I used to work, though there it was an ultrasonic cleaner using TCE, and it used the vapour phase to clean the fluid, as you could collect the drip off condensed liquid into a bucket and concentrate the dirty fluid down to a sludge for dirt removal. That would take the dirtiest castings you could find and leave them as bare clean white castings. Would strip a PCB of the resin ( except for the one conformal coat that survived no matter what) and all printed and painted parts except the copper and solder in around 3 minutes.
I'm actually very strongly considering trying this. I was thinking that the best approach would be one like you are describing; basically just go really slowly with everything. I can live with more than a 6 minute cycle if it means less wasted fluid.
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Vapour phase soldering machine from Wenesco USD5500 on their website.
http://www.wenesco.com/vapor.htm (http://www.wenesco.com/vapor.htm)
A solid state diode laser source is sufficient for the task. New source and fiber under 2000 Euro new or under USD300 on ebay of questionable provenance.
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that configuration is very widely used for a cleaning technique called vapor degreasing. they usually can be set up with two tanks and when the working tank is full of dirt, it is "boiled down" to distill the solvent into the clean tank.
the solvents used for vapor degreasing are quite aggressive (high KB figures) compared to the inert fluids used for vapor soldering (should have KB at or near zero). They can sometimes cause leaching of plastic resins though, so this is something to test.
in the video from 3M, they are doing selective soldering using a low melting point alloy for attaching heat sinks. So they need to use a fluid with a boiling point between the melting point of their solder (140° C) and the solder in the processor package (probably SAC305: 217° C). The Fluorinert FC-40 has a bp of 155° C, so it is perfect in this application. Galden fluids have a boiling point of 230° C because they are designed for primary soldering.
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that configuration is very widely used for a cleaning technique called vapor degreasing. they usually can be set up with two tanks and when the working tank is full of dirt, it is "boiled down" to distill the solvent into the clean tank.
the solvents used for vapor degreasing are quite aggressive (high KB figures) compared to the inert fluids used for vapor soldering (should have KB at or near zero). They can sometimes cause leaching of plastic resins though, so this is something to test.
in the video from 3M, they are doing selective soldering using a low melting point alloy for attaching heat sinks. So they need to use a fluid with a boiling point between the melting point of their solder (140° C) and the solder in the processor package (probably SAC305: 217° C). The Fluorinert FC-40 has a bp of 155° C, so it is perfect in this application. Galden fluids have a boiling point of 230° C because they are designed for primary soldering.
This is true, but you can get Fluorinert FC-70 with a boiling point of 215C. I'm thinking they designed this for the pre-RoHS era and never updated their plans.
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vapor phase can be done reasonably cheap at home.
get an inductive single plate heater ( 50$ , amazon ) why ? no need to drill holes in the holding tank to shove a heating element in
get a nice high cooking pot compatible with inductive heaters. cooking pot needs a metal lid. if you can find a 'turkey fryer' style pot ( those are really deep and come with a basket )
put half an inch of galden in the pot and switch on.
use a fryer basket : put in the board on pegs so it does not contact the basket.
hang the basket so the board hangs in the cloud of vapor.
put on the lid. around the top of the pot : run metal tubing a couple of times and run cold water ( a bucket of water with some ice in it and a 12 volts dc pump will do the trick.
the same for the lid : attach a spiral of metal tubing and run cold water there as well.
you may want to attach an inverted cone to the lid so the condensation droplets fall down on the cone and then roll towards the side.
hmm.. difficult in words. lemme draw it
hang on
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there ya go.
the cooled cone attached to the lid condenses the vapor and makes it run down towards its edges where the droplets fall back down , away from the pcb.
there is a swiss dude that built one on this principle. works well aparently
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What happens to the working fluid in presence of flux in solder paste?
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What happens to the working fluid in presence of flux in solder paste?
nothing - it's inert
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Does it get contaminated?
If so how is contamination handled? distillation?
Is contaminated how is the equipment affected by contaminants?
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You are only using the vapour, so it is not worried much by flux and other residues. Eventually you just run it with a drip tray collecting the condensed liquid till it is dry below and with the now distilled liquid up in the top. Then clean the boiler area and reuse the fluid.
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(1) do you need to do anything in terms of pre-heating your board before it goes into the vapour?
(2) How "thick" is the vapour layer above the liquid.
(3) Im thinking that a 'lid' that has a stack of aluminium heat sinks that sits over the tank might be quite good a well.
(4) If the board is sitting flat, after it is raised out of the vapour, the vapour could potentially condense and sit on the board, ( once its cold ). Maybe when you pull it up, it needs to be angled once the solder is solid?
(5) Double sided.. Just rely on surface tension?
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(1) do you need to do anything in terms of pre-heating your board before it goes into the vapour?
Not really. Just don't heat too quickly, so the vapour has time to warm the components through. While the core of the components is still drawing heat from the surface you won't get a good flow of solder. That might not be a big issue with small components, but it can be with big chunky power ones.
(2) How "thick" is the vapour layer above the liquid.
(3) Im thinking that a 'lid' that has a stack of aluminium heat sinks that sits over the tank might be quite good a well.
I'm not clear what you are trying to achieve there? It seems like that just going to make the fluid condense on the lid instead of the board. The whole things works by the latent heat of condensation ending up in the components.
(4) If the board is sitting flat, after it is raised out of the vapour, the vapour could potentially condense and sit on the board, ( once its cold ). Maybe when you pull it up, it needs to be angled once the solder is solid?
That isn't a problem when things are done right. If the vapour pressure is greatly reduced while the board is still warm, the fluid evaporates. The board should come out dry.
(5) Double sided.. Just rely on surface tension?
Yes. Make sure nothing jolts that board before soldering. :) Alternatively glue spot.
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(1) do you need to do anything in terms of pre-heating your board before it goes into the vapour?
(2) How "thick" is the vapour layer above the liquid.
(3) Im thinking that a 'lid' that has a stack of aluminium heat sinks that sits over the tank might be quite good a well.
(4) If the board is sitting flat, after it is raised out of the vapour, the vapour could potentially condense and sit on the board, ( once its cold ). Maybe when you pull it up, it needs to be angled once the solder is solid?
(5) Double sided.. Just rely on surface tension?
1) yes, otherwise you will risk tombstoning or wicking. It's actually more of a problem with smaller components apparently because they will heat much faster than the pads. 150C preheat makes this problem basically go away. Source is in one of my previous posts in this thread. Usually an different batch oven is used, but that's only because in production everything needs to go super fast.
2) depends on the amount of heating. Seems like as long as the board is in the vapour and not the fluid it will be ok. If you're talking about density, it is heavier than air.
3) yes, or maybe some of those watercooling blocks from overclocking kits too? coppice: you want the fluid to condense on the lid so that it doesn't escape.
4) I don't see why you couldn't just wash the board with distilled water in place after everything had cooled down, then just run the thing on 120C for a bit to evaporate the water. When I finally get hold of some galden or fluorinert (I'm trying to get 500mL, but the cheapest I've got so far is about AU$1200 for 3.8L), I think it would be good to do some experiments to see just how much loss you get when you do something like this.
5) thermosetting epoxy designed for smd is not that expensive, and I've got it from RS in the past in plastic syringe form. I'd post the link, but I'm getting "RS Online is temporarily unavailable."
Cleaning the fluid should be straightforward. You can get a liebig condenser on ebay from china for like $30.
free_electron: nice pic. what did you draw it in?
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3) yes, or maybe some of those watercooling blocks from overclocking kits too? coppice: you want the fluid to condense on the lid so that it doesn't escape.
As the vapour is heavier than air, why would it escape? You aren't going to lift the lid until the vapour pressure has dropped.
5) thermosetting epoxy designed for smd is not that expensive, and I've got it from RS in the past in plastic syringe form. I'd post the link, but I'm getting "RS Online is temporarily unavailable."
The material is cheap, but applying it can be a pain. People don't really like doing this, unless its being done by a fully automated machine that tightly controls quantities. If you dispense just a little too much, or don't place it accurately, it can spread onto the pads, especially if the parts are very small.
Take what I say with a pinch of salt. I'm basing what I say on results in the 1980s with lower temperature fluid and leaded solder.
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3) yes, or maybe some of those watercooling blocks from overclocking kits too? coppice: you want the fluid to condense on the lid so that it doesn't escape.
As the vapour is heavier than air, why would it escape? You aren't going to lift the lid until the vapour pressure has dropped.
Actually, this is not true in a batch-like system. See the CPU soldering video above; there is no lid on the vessel, just a cooling jacket. You will also still get some loss due to natural diffusion even though it is denser. I'm not sure if this is worth worrying about, but the stuff is expensive so someone needs to test that.
Also, I'm not sure I would feel comfortable having a 100% sealed container being vigorously heated. It might also increase the BP of the fluid. Again, I think someone needs to actually measure the pressure and/or BP changes to see if these are negligible or not.
Does anyone have any contacts at 3M/dupont/solvay that they can put me in touch with? I've already tried contacting 3M AU but they (understandably) haven't got back to me yet.
Take what I say with a pinch of salt. I'm basing what I say on results in the 1980s with lower temperature fluid and leaded solder.
Thanks for your opinion anyway. It's useful to get many points of view and many people's experiences.
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There are some interesting videos from the manufacturers of these machines.
This company has several videos: This one demonstrates a jig that can desolder a BGA using the same machine and process as for soldering:
ASSCON Desoldering System | English (https://www.youtube.com/watch?v=LQ_4Kkj1UFc#ws)
Depopulating a whole board would take ages, but it's not uncommon to only rework one large component. The large BGAs are also the hardest to rework with hand tools.
Especially interesting is their top-line product, the VP6000, which has a vacuum system. I assume it is used to recover more of the fluid, or to make the boards dry faster. They have options for filtering flux residue and for convection coolers to enhance board drying.
It also shows that they can calibrate the process using a live device inserted into the vapor bath.
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There are some interesting videos from the manufacturers of these machines.
This company has several videos: This one demonstrates a jig that can desolder a BGA using the same machine and process as for soldering:
ASSCON Desoldering System | English (https://www.youtube.com/watch?v=LQ_4Kkj1UFc#ws)
Depopulating a whole board would take ages, but it's not uncommon to only rework one large component. The large BGAs are also the hardest to rework with hand tools.
Especially interesting is their top-line product, the VP6000, which has a vacuum system. I assume it is used to recover more of the fluid, or to make the boards dry faster. They have options for filtering flux residue and for convection coolers to enhance board drying.
It also shows that they can calibrate the process using a live device inserted into the vapor bath.
Nice, thanks for sharing.
Asscon (related to siemens?) actually has some recent patents on the vacuum. It outgasses (http://en.wikipedia.org/wiki/Outgassing) the solder to extract any flux pockets caught inside the joints that would cause solder voids. See http://www.smtnet.com/library/files/upload/Vapor-Phase-Soldering.pdf (http://www.smtnet.com/library/files/upload/Vapor-Phase-Soldering.pdf)
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1) yes, otherwise you will risk tombstoning or wicking. It's actually more of a problem with smaller components apparently because they will heat much faster than the pads. 150C preheat makes this problem basically go away. Source is in one of my previous posts in this thread. Usually an different batch oven is used, but that's only because in production everything needs to go super fast.
Tombstones are just painful. We get the odd ones happening in our reflow oven from time to time. For a small batch / prototype system, I wonder if it will be sufficient to heat the board in a convection oven, and then drop on the tray ( gently! )
2) depends on the amount of heating. Seems like as long as the board is in the vapour and not the fluid it will be ok. If you're talking about density, it is heavier than air.
I was more thinking about physically how high the vapour cloud will be, and how big the "zone" between 'air' and the vapour will be. ( there will be some 'transition zone' )
[/quote]
3) yes, or maybe some of those watercooling blocks from overclocking kits too? coppice: you want the fluid to condense on the lid so that it doesn't escape.
[/quote]
Now that sounds like quite a good idea. Though i have some good pelters and some fans, that would be very effective as well, and i save yet more water pumping around.
4) I don't see why you couldn't just wash the board with distilled water in place after everything had cooled down, then just run the thing on 120C for a bit to evaporate the water. When I finally get hold of some galden or fluorinert (I'm trying to get 500mL, but the cheapest I've got so far is about AU$1200 for 3.8L), I think it would be good to do some experiments to see just how much loss you get when you do something like this.
It may not even be a problem. but looking at another machine it seems they have implemented some fans that blow air over the board once its out of the vapour. My guess is that this helps dry them. ( a bit like squiring compressed air on a board, that you've washed in IPA.. )..
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Does anyone have any contacts at 3M/dupont/solvay that they can put me in touch with? I've already tried contacting 3M AU but they (understandably) haven't got back to me yet.
Been in touch with solvay, and am waiting for an answer.
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Quote from: jeremy on Today at 09:47:20 PM (https://www.eevblog.com/forum/index.php?topic=41781.msg592498#msg592498)
Asscon (related to siemens?)
I looks like the use a SIEMENS PLC to control the system (logo on LCD screen).
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2) depends on the amount of heating. Seems like as long as the board is in the vapour and not the fluid it will be ok. If you're talking about density, it is heavier than air.
I was more thinking about physically how high the vapour cloud will be, and how big the "zone" between 'air' and the vapour will be. ( there will be some 'transition zone' )
The vapour cloud height should actually be a function of the heating amount. My simple understanding of chemistry says that you will get more diffusion by injecting more energy into the system, hence more height. In the 3M video, they clearly solder 2 LGA1155 cpus in height plus some, so that's 37.5mm * 2 + a bit >= 75mm of "soldering zone". Sure, its a lower boiling point fluid, but it's a ballpark at least.
Some interesting historical patents (I found these on the derwent innovation index which I have access to, but they are all on google patents for free):
US 4394802 A - Counter-convection vapor control system; similar to free_electron's pic
US 4549686 A - Vapor phase soldering using perfluorotetradecahydrophenanthrene (C14 F24); this seems like the original commercial patent, but uses CFCs
US 4628616 A - Vapor tank; Hitachi patent on a vapour phase soldering tank
US 4996781 A - Vapor reflow type soldering apparatus with an improved flux separating unit; a later Hitachi patent
US 4681249 A - Vapor phase soldering apparatus; a continuous soldering system
US 4806662 A - Fluids having an oxetane structure and improved characteristics for special applications; the original "galden" patent
The original galden was created by a company known as Ausimont in Italy. Since galden lists Italy as the contact on the msds I became a little suspicious, so I did a bit of poking around and sure enough I also discovered that they merged with solvay later on: http://ec.europa.eu/competition/mergers/cases/decisions/m2690_en.pdf (http://ec.europa.eu/competition/mergers/cases/decisions/m2690_en.pdf)
Will post if I find any more interesting stuff.
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US 4549686 A - Vapor phase soldering using perfluorotetradecahydrophenanthrene (C14 F24); this seems like the original commercial patent, but uses CFCs
The fluids we used in the early 80s for leaded soldering were CFCs. The electronics industry used to put enormous quantities of CFCs into the air back then. Boards were mostly cleaned with CFC113, commonly referred to as "trik", and the stuff was cheap enough that it was allowed to evaporate quite freely.
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A few more (not sure if these are available on google patents):
DE20300375-U1 - Cooler for workpieces or components under cooled vacuum dome, especially in vapor phase vacuum soldering installation; Asscon patent from 2003
DE20300374-U1 - Assembly for temp. treatment of workpieces or components in controllably heated vacuum dome; similar to above, also from asscon
US 20070194083 A1 - Process and device for soldering in the vapor phase; IBL patent on using a vacuum to stop void forming inside joints. Still valid! This is the company that sells the US$6k/AU$26k ( :-// ) machine mentioned earlier
US 4871109 A - Vapor phase soldering using certain perfluorinated polyethers; chemistry patent from everyone's favourite chemical company: Monsanto
http://www.emeraldinsight.com/doi/abs/10.1108/SSMT-10-2013-0028 (http://www.emeraldinsight.com/doi/abs/10.1108/SSMT-10-2013-0028) - A very recent paper on solder voids due to vapour phase soldering
I read the paper but its not free access so I'll give you all the short version: yes you get voids without a vacuum. RoHS or not doesn't seem to make a difference.
http://www.emeraldinsight.com/doi/pdfplus/10.1108/eb037911 (http://www.emeraldinsight.com/doi/pdfplus/10.1108/eb037911) - Voids in BGAs.
Again, not free, but the summary is:
- convection oven with changeable air/nitrogen supply
- all BGAs originally came with no voids (verified by xray), Sn63 balls with ~1.5mm pitch
- no vacuum was used
- going to higher temps means more % voids
- flux/paste solvents with lower boiling points tend to cause more voiding (solder paste solvents are worse)
- recommended profile with worst solder paste caused about 1-2% voiding, best was 0.5%
- mesh size of the paste balls does show a minor trend towards smaller being better (200-300um instead of 500um), but it is so slight that I'm not buying it
- reflow atmosphere doesn't matter (air or nitrogen) with respect to void formation
- flux activity doesn't matter
Hopefully someone else is finding this as interesting as I am :P
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How do they use the vacuum?
If you apply vacuum the boiling point of liquid drops highly, so the temperature necesary for the soldering can't be reach.
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How do they use the vacuum?
If you apply vacuum the boiling point of liquid drops highly, so the temperature necesary for the soldering can't be reach.
If you look in the patent, it has a separate chamber which is pulled under a vacuum. So while the solder is still liquid, it the board moves from the vapour blanket to the chamber and the vacuum does its work. Cooling isn't really a problem, because it's a vacuum!
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So they remove gas bubbles and liquid from the board, avoiding gaps.
Cooling is important for the solder (Pb, Sn,etc), not for the soldering liquid, of course.
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Asscon (related to siemens?)
They are both German; but I get the sense that they use all COTS PLC equipment, and Siemens is a big player in PLCs.
I haven't seen it mentioned here yet, but vapor phase is an oxygen-free process. As the board is lowered into the vapor cloud, the condensing liquid forms a film all over it and so there is no oxygen at the joint during reflow. Separate pre-heating is not needed because the ramp rate is controlled by the heat input to the liquid.
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One last interesting patent: US 4523039 A - Method for forming perfluorocarbon ethers. Check out the number of patent references, mostly by Solvay.
Basically get a polyether, add fluorine and heat up like crazy. I think this one is best left to the experts...
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The Wenesco Machine looks not too bad, and actually demonstrates how simple the system probably is. There is a lot of potential here to engineer a solution that is a lot more complex than it needs to be, i suspect.
(http://www.wenesco.com/Images08/m13.jpg)
(http://www.wenesco.com/Images04/A66new.jpg)
(http://www.wenesco.com/images/m10.jpg)
Its a bucket with a lifter in it!!
I'm seeing a project coming up here. I'm thinking that it would be wise to start with building an experimental system. I had thought about using the deep fryer, but the issue is that the element will need to be completely covered, and that in itself will require a lot of the expensive juice. time to rethink the heating, just a little bit.
What seems apparent to me, is that a pretty decently tall system will be your friend here. I'm thinking you probably want a tank that is a minimum of 600-700mm deep.
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Like Vincent said use an external heater. Either a simple solid plate that you hard solder to the bottom of the chamber, and insulate with a lot of high temperature insulation, or use the Free electron style of an induction heater coil coupling energy directly into the base plate.
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How do they use the vacuum?
If you apply vacuum the boiling point of liquid drops highly, so the temperature necesary for the soldering can't be reach.
If you look in the patent, it has a separate chamber which is pulled under a vacuum. So while the solder is still liquid, it the board moves from the vapour blanket to the chamber and the vacuum does its work. Cooling isn't really a problem, because it's a vacuum!
If you look at the video for the VP6000 (https://www.youtube.com/watch?v=C0dYtifEw8Q&list=PL6DAFE2AFAF9CFEAC&index=7 (https://www.youtube.com/watch?v=C0dYtifEw8Q&list=PL6DAFE2AFAF9CFEAC&index=7)), it looks like the process is this:
- Load carrier into entry chamber.
- Transfer carrier into process chamber.
- Lower carrier into soldering zone.
- Lift carrier out of soldering zone.
- Activate drying heat and vacuum.
- Transfer carrier into entry chamber.
- Cool.
- Unload.
The drying heat appears to be a halogen tube lamp. Presumably the drying heat also keeps the solder molten long enough for the vacuum to properly degas it, and also controls the cooling speed to avoid quenching. The vacuum system (which is very nicely labeled! Too bad more of the labels aren't legible in even the HD video) appears to use filters to recover the process fluid. I'm kind of surprised they didn't go for a cold trap, since the system already has a water cooling loop, but I guess the filters are effective enough.
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no isolation of the wires here: http://www.ibrtses.com/projects/vapourphasesoldering.html (http://www.ibrtses.com/projects/vapourphasesoldering.html)
I like the "bigass beaker" approach. Instead of immersion heating, throw a steel puck in the bottom and stick the whole thing on an induction heater. Maybe even find a metal with a lower curie point for the puck so it can't overheat if it "runs dry" -- once it hits that point, it should just stop being heated by the magnetic field.
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...
Its a bucket with a lifter in it!!
I'm seeing a project coming up here.
you and me both. now to find some of this pesky galden...
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Yes.. I thought Wenesco had a good approach in their batch oven.
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What do you make of the "cover zone" layer that they show in their machine? Thats got me a bit confused.
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One of the distributors is Hawker richardson in .au
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wonder if their is a cheap chinese knock off that is like garden LS230
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ok, 5kg is $AUD1420+GST. that is 2750ml or so.
Anyone keen to split this up? Suggest 5 segments of 500ml ( allowing a wee bit of of wiggle room for any waste when repackaging )
That would be $284 for 500ml, ( 905g ) + Courier, Ex Melbourne.
I'll take 1kg to start, things off, so just need three others.
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I'm up for some. PM sent.
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That wenesco machine seems to have a two zone system. I'm wondering, if they use two different fluids.. If you stuck two different fluids in the same container, and heated them, would you get two different vapour zones? one one top of the other?
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That wenesco machine seems to have a two zone system. I'm wondering, if they use two different fluids.. If you stuck two different fluids in the same container, and heated them, would you get two different vapour zones? one one top of the other?
In my research I found that people used to use two layers to increase the vapour retention and decrease the thermal gradient for the board. Galden SVP is the second fluid name, where svp stands for Soft Vapour Phase. See: http://amtest.bg/products/Asscon/Galden%20PFPE%20Fluids%20Data%20Sheet.pdf (http://amtest.bg/products/Asscon/Galden%20PFPE%20Fluids%20Data%20Sheet.pdf)
I also found that this has been somewhat phased out. Not sure why though.
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Thinking about the heating element/system.
If you look at pro kitchen equipment, they only place a heater under the stainless steel container for temperatures up to 90 degrees C (like warmwater baths, bain marie).
Above those temperatures like in frying equipment (180 to 200 degrees C typically) they place the heating element inside the stainless steel container making contact with the fluid.
So would it be allowed for this vapour chemical to be in direct contact with the heating element or would that not be advised?
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Thinking about the heating element/system.
If you look at pro kitchen equipment, they only place a heater under the stainless steel container for temperatures up to 90 degrees C (like warmwater baths, bain marie).
Above those temperatures like in frying equipment (180 to 200 degrees C typically) they place the heating element inside the stainless steel container making contact with the fluid.
So would it be allowed for this vapour chemical to be in direct contact with the heating element or would that not be advised?
Perfluorocarbons decompose into fluorine gas and HF, and the MSDS for galden lists >290 as the decomposition temp. However, before that temp, this class of chemicals are one of the most inert chemicals know to mankind (http://www.epa.gov/chemrtk/pubs/summaries/perfluro/c13244rt3.pdf (http://www.epa.gov/chemrtk/pubs/summaries/perfluro/c13244rt3.pdf)). So I don't think there is any problem having direct contact, as long as your element doesn't go over 290C. I was thinking of just using some sort of iron core element and putting a thermocouple in there.
Also, this: http://www.ebay.com.au/itm/MULTICORE-SOLDERS-VAPORETTE-/111436980268 (http://www.ebay.com.au/itm/MULTICORE-SOLDERS-VAPORETTE-/111436980268) which was an early commercial system, used external heating. But no temp control?
I am not a chemist though, ymmv, etc.
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In my research I found that people used to use two layers to increase the vapour retention and decrease the thermal gradient for the board. Galden SVP is the second fluid name, where svp stands for Soft Vapour Phase. See: http://amtest.bg/products/Asscon/Galden%20PFPE%20Fluids%20Data%20Sheet.pdf (http://amtest.bg/products/Asscon/Galden%20PFPE%20Fluids%20Data%20Sheet.pdf)
I also found that this has been somewhat phased out. Not sure why though.
I found that link as well, but it seems its disappeared as well. It would be interesting to know why they don't use it.
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Thinking about the heating element/system.
If you look at pro kitchen equipment, they only place a heater under the stainless steel container for temperatures up to 90 degrees C (like warmwater baths, bain marie).
Above those temperatures like in frying equipment (180 to 200 degrees C typically) they place the heating element inside the stainless steel container making contact with the fluid.
So would it be allowed for this vapour chemical to be in direct contact with the heating element or would that not be advised?
My concern with having the heater in the tank is not to do with contaimination, its to do with the amount of fluid you'll need in your tank to cover the element. In my home deep fryer, i'll need 3.5l minimum to cover it. and when we heat it, and evaporate it, we'll have even less covering the elements. they will just overheat. That machine that we were looking at before claims it will work with just 1 quart ( ~1 litre ). By having external heating it will be much easer to avoid this issue.
Deepfryer is off the list of suitable things to use.. I'm also thinking we want to make it a *lot* deeper than your average deep fryer.
So, excuse the very bad pun.
"Deep fryer is for making chips, not soldering them"
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Deepfryer is off the list of suitable things to use
It was never my intention to advise to use a deepfryer, I was merely saying that if you look at pro kitchen equipment that heats a bath above 100oC they do not put the heating element below and against the bottom of a stainless steel container anymore. Now there has to be some reason for that?
I can think for instance that it is not safe to use a heater that way with such high temperatures since it will radiate in all directions so the whole area will have that temperature so the electrical wiring etc has to withstand that temperature. So heating from below with a standard heating element is probably not an option. Thats all I was trying to say.
Than I would indeed rather use the induction method FreeElectron has given.
You need a temperature of 230oC for the leaded solderpaste and a bit above that for the unleaded, so these are quite high fluid temperatures.
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You're right Kjelt, but I think I would rather have something made of pyrex so I can see inside. I'm currently liking the idea of using induction and putting a chunk of iron inside the vessel.
edit: Although the recommended reflow temperature for SN100C with vapour phase is 230C - 245C from here (http://www.aimsolder.com.au/index.php/solder/solder-paste/92-nc257-2-sn100cr-no-clean-lead-free-solder-paste)
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free_electron: nice pic. what did you draw it in?
Altium silkscreen layer >:D
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Thinking about the heating element/system.
If you look at pro kitchen equipment, they only place a heater under the stainless steel container for temperatures up to 90 degrees C (like warmwater baths, bain marie).
Above those temperatures like in frying equipment (180 to 200 degrees C typically) they place the heating element inside the stainless steel container making contact with the fluid.
So would it be allowed for this vapour chemical to be in direct contact with the heating element or would that not be advised?
My concern with having the heater in the tank is not to do with contaimination, its to do with the amount of fluid you'll need in your tank to cover the element. In my home deep fryer, i'll need 3.5l minimum to cover it. and when we heat it, and evaporate it, we'll have even less covering the elements. they will just overheat. That machine that we were looking at before claims it will work with just 1 quart ( ~1 litre ). By having external heating it will be much easer to avoid this issue.
Deepfryer is off the list of suitable things to use.. I'm also thinking we want to make it a *lot* deeper than your average deep fryer.
So, excuse the very bad pun.
"Deep fryer is for making chips, not soldering them"
like i said. get a turkey fryer. those are really deep.
throw a iron metal plate inside the fryer at the bottom. ( turkey fryers are aluminium ... )
put fryer on induction heater.
should work ...
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Instructions for Weller machine.
http://www.egmont.com.pl/cooper/instrukcje/OI_WAM3000_GB.pdf (http://www.egmont.com.pl/cooper/instrukcje/OI_WAM3000_GB.pdf)
They use the HT Fluid, along with a couple of others. Having talked with one of the suppliers, the difference between the LS and the HT, is the tolerance of the boiling point. The HT, is not as precise as the LS, but its also less than half the price. $121/kg vs $270/kg.
The beaker based project used HT, Weller are using HT, and if you are prepared to accept a small ( maybe 5 degrees ) difference vs 1 degree variation in boiling point, ( i'm asking for clarificaiton of this point ), then HT might be well acceptable.
The Weller machine only requires 1 litre of fluid as well.
I'm tending to be thinking that for my application HT might be just fine..
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free_electron: nice pic. what did you draw it in?
Altium silkscreen layer >:D
So I'm not the only one that does drawings in PCB software because I can't be arsed to learn a proper CAD package then...!
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This ebay offer is very expensive for what is on offer.
A new Wenesco of similar construction and technological approach, NEW and under warranty is USD5500.--
NO LINKS TO WENESCO other than common sense.
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The seller doesn't really expect to get $5k, that is an optimistic estimate for negotiation's sake.
The problem is that a machine of that vintage may not be designed for the same parameters as is used today. It says it uses a type of Fluorinert, but not what solder alloy it expects. Not a RoHS solder, anyway.
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Interesting, it's not LS230 but HT230. Both have the same CAS numbers and structural formulae. Anyone know a chemist who can shed some light on this?
It looks like the Galden LS series is a mixture of perfluorinated polyethers of varying chain length, varying molecular weight in the 700-1000 range, it's not just one chemical.
So, basically, they can just separate it into whatever boiling-point range is desired by fractional distillation, just like distillation of hydrocarbons at an oil refinery.
http://www.solderconnection.com/specsheets/Galden_LS_-_MSDS.pdf (http://www.solderconnection.com/specsheets/Galden_LS_-_MSDS.pdf)
Galden HT seems to be similar but with a higher BP range, higher than soldering will need, targeted as a chemically-stable coolant for specialist applications, eg. CVD, ion implanters, plasma etching and stuff at applicable apparatus temperatures, especially where chemicals or reagents are involved that may react with a non-perfluoro coolant (uranium enrichment, for example, is one application they mention). The chemical formula is the same, but the typical length of the polymer, the average "m" and "n" numbers in the formula, will be higher. And the CAS number is the same because it's the same general family of chemicals with one CAS number as a group.
in the video from 3M, they are doing selective soldering using a low melting point alloy for attaching heat sinks. So they need to use a fluid with a boiling point between the melting point of their solder (140° C) and the solder in the processor package (probably SAC305: 217° C). The Fluorinert FC-40 has a bp of 155° C, so it is perfect in this application. Galden fluids have a boiling point of 230° C because they are designed for primary soldering.
There are a whole series of different chemicals (and mixtures) under the Fluorinert brand, just like there are under the Galden brand.
Fluorinert FC-70 is perfluorotripentylamine, for example, and any perfluorotripentylamine from any vendor is identical to FC-70 from 3M.
FC-40 is a combination of two compounds - perfluorotributylamine and perfluorodibutylmethylamine - but overall its composition is less complicated than the complex-mixture Galden fluids. Also these ones are perfluorinated trialkylamines, not ether polymers, but they're still perfluorinated, they're still really inert, and their basic properties are somewhat the same.
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It looks like the Galden LS series is a mixture of perfluorinated polyethers of varying chain length, varying molecular weight in the 700-1000 range, it's not just one chemical.
So, basically, they can just separate it into whatever boiling-point range is desired by fractional distillation, just like distillation of hydrocarbons at an oil refinery.
Im with you on this conclusion now. and maybe even you get a mixture of different chain lengths, which average out to give you a specific temp?
Galden HT seems to be similar but with a higher BP range, higher than soldering will need, targeted as a chemically-stable coolant for specialist applications, eg. CVD, ion implanters, plasma etching and stuff at applicable apparatus temperatures, especially where chemicals or reagents are involved that may react with a non-perfluoro coolant (uranium enrichment, for example, is one application they mention). The chemical formula is the same, but the typical length of the polymer, the average "m" and "n" numbers in the formula, will be higher. And the CAS number is the same because it's the same general family of chemicals with one CAS number as a group.
HT and LS grades are avaialable over the same range of BP's.. You can get LS230 and HT230.. Both have a nomial boiling point of 230C. Theres LS200 ( which would be good for lead solder i guess ) and an HT200.
I have two suspicions.
(a) the product may in fact be the same thing marketed at two different products, for two different end uses.. one has a higher price tolerance than the other
(b) the LS product is 'refined' more accurately than the HT, so the actual BP, may be sitting in a smaller range than the HT.
I've seen quite a number of commercial machines specifying HT grade, and the DIY projects we've seen all seem to use HT.
Its less than half the price.. If we have a temp range that is just a wee bit wider, does it actually matter, provided its not too far out?
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perfluoroalkylamines like Fluorinert were used as blood substitutes because of their ability to dissolve oxygen. This is not desirable for soldering because oxygen reacts with the metals, making a duller joint that wets more poorly.
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Thanks Luke for the tips. I agree, after reading the patents they seem to just make a big batch of perfluorinated polyethers of varying chain lengths (get polyethers, add fluorine, bake at 180C until golden brown, etc) then distill it into the different boiling points. It's interesting that HT is so much cheaper, and potentially not necessary for vapour phase. If weller recommends HT, I trust them with all my other soldering gear, so I don't see a problem.
It's kind of strange that the other manufacturers use LS actually...
I found a guy in australia who sells quite large diameter and length borosilicate tubes. Also, you can get a 4L beaker with a ~160mm ID on Amazon for not too much. This plus a stainless "induction interface disk" (google it) seems like it could be a decent way to start. Now I'm trying to think about how to raise the board gently when potentially the balls are still liquid. Or perhaps since it is a hobby system and I only need one board, just turn off the heating and wait for it to cool. Suggestions welcome!
Edit: I was also thinking about just putting some ball bearings in the bottom of the beaker. What do you all think? Galden has basically no chance of exploding, so I can't see a problem there.
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free_electron: nice pic. what did you draw it in?
Altium silkscreen layer >:D
So I'm not the only one that does drawings in PCB software because I can't be arsed to learn a proper CAD package then...!
Altium pcb has almost everything regular 2d cad has. Corrdinate system, multip,e layers , lines arcs polygons , you can place dimensions , rotate stuff, there is a library system for often used symbols. You can load and save dxf to be compatible with the rest of the world.
And you dont have to learn some awkward tool. Works perfectly fine for me !
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free_electron: nice pic. what did you draw it in?
Altium silkscreen layer >:D
So I'm not the only one that does drawings in PCB software because I can't be arsed to learn a proper CAD package then...!
I've done it :) but now I use http://www.plm.automation.siemens.com/en_gb/products/solid-edge/free2d/ (http://www.plm.automation.siemens.com/en_gb/products/solid-edge/free2d/)
free and extremely easy to use
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And you dont have to learn some awkward tool. Works perfectly fine for me !
I guess once you've learned the quirks of Altium, you've got no brain cells left.
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Difference between HT230 and LS230
According to Matweb.com there are some very minor differences between LS230 and HT230. Heres the comparison
The LS230 exhibits slighlty ( 2% ) higher Heat of Vaporisation, and slighty higher Specific Heat Capacity. ( 1.5% )
For all practical purposes Galden HT230 and Galden LS230 appear to be very very similar and for this application i don't think its going to be an issue.
I've found three commercial systems that specify Galden HT230 as their working fluid, as well as several DIY projects.
That being the case, I propose that getting some HT230 seems to be ok.
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And then there was this. This is the 'official' word From the people who make it.
"Solvay Solexis understands that Galden® HT Grades are used as Soldering Fluids in Vapor Phase Soldering Equipment. These fluids have a wider molecular weight distribution and are designed for use as Heat Transfer and working fluids in closed systems. They consist of a mixture of elements belonging to the same chemical family of perfluoropolyethers having varying boiling points, including those with boiling points lower than the nominal values. These low boiling components preferentially evaporate during the operation of the Vapor Soldering Machines. This phenomenon leads to higher losses of the fluids as well as a shift towards higher vapor temperature with time – temperature shift.
As a result, the cost of the vapor phase soldering process and the fluid emissions to the environment increase. The latter defeats the purpose of moving towards lower environmental friendly lead-free soldering.
We believe that Vapor Phase Soldering produces the best quality soldered joints. In addition, it is the most economical, environmental-friendly and the safest soldering process compared to other technologies such as convection ovens that operate at higher temperatures due to the poor heat transfer efficiency of air and other gases.
The Galden® LS and HS fluids are specifically designed with very narrow molecular weight distribution for the Vapor phase Soldering process by a stricter control of the molecular weight distribution during their production. This eliminates the above mentioned problems.
In addition, in order to improve the performance of the Galden® HT grades in closed loop systems, Solvay Solexis has decided to modify the specifications of Galden® HT grades with emphasis on the properties specific to these uses, such as viscosity.
This would make the Galden® HT grades even less suitable for use in Vapor Phase Soldering Process. Solvay Solexis will not be guarantee to provide technical assistance
?to problems arising out of the wrong use of our Galden® HT grades in Vapor Phase Soldering Equipment.
At the same time Solvay Solexis will be at our customer disposal to make the transition form Galden® HT grades to Galden® LS and Galden® HS grades as smooth as possible.
Solvay Solexis also guarantees the supply of the Galden® LS and HS grades for current and future requirements..
We request you to kindly inform your customers of these changes and help them to move to a better process with lower fluid losses and lower emissions."
PDF attached, what do you make of this.. Is this a marketing thing, or is this for real.
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PDF attached, what do you make of this.. Is this a marketing thing, or is this for real.
It seems to me like it's for real. As a chemical engineer, everything you quoted from Solvay Solexis makes logical sense.
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Ok, but to play devils advocate here:
Weller and others recommend HT. So it legitimately performs well. HT is 1/2 the price of LS. Let's assume that solvay doesn't have bigger margins on the LS product, but that might not be true given that they have no competitors (they do in heat transfer though: fluorinert, krytox, etc). If you have a sealed batch vapour phase system, then it is effectively a closed loop system so you should expect basically no losses except what sticks to the board.
I can see the that the LS would be better for an inline system which is perpetually open, but will the losses offset the savings from using HT in a batch oven?
I also think that having some lower boiling point fluids would be better; it will make the temperature gradient of the vapour cloud much less steep.
Can anyone shed any light on why fluid viscosity really matters in a batch oven? I can't think of anything.
Also a lot of this kind of reeks of marketing:
"The latter defeats the purpose of moving towards lower environmental friendly lead-free soldering."
This makes sense superficially, but it doesn't really make technical sense. The lead-free soldering move had nothing to do with ozone or CFCs. We can of course argue all day if it is actually better for the environment ;), but lead free (afaik) uses the same amount of fluxes, generates the same amount of gas, etc if not more due to the higher temps required.
The actual fluid losses aren't quantified. I'm pretty sure if it was a huge amount, they would use the figure to make their argument. They have a technical audience after all. Something like "in our testing, we found that HT losses were 250% greater than LS at 230C". After reading the technical detail in the PDF, I'd be willing to bet that they've done the test and didn't see an enormous difference.
In the slides, they state that Galden is not a CFC, not toxic, accidental spills/release is ok (even on food!), etc. But when it comes to LS vs HT, HT is pretty nasty stuff for the environment? Um :-//
tldr; do the losses by using HT really account for a doubling in price? My guess is no, or they would have been a little more technical about the whole thing.
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Now I'm trying to think about how to raise the board gently when potentially the balls are still liquid.
I think your biggest challenge here is a smooth motion without rocking and too fast accelaration/deceleration.
A quick though about rocking/shaking is to use guidance rails like CNC machines do.
They are now so accurate the backlash is within 0,01 mm even when milling steel so not a problem for your system.
You have a lot of choice, for instance IGUS DryLin Linear Guide or even HIWIN Carriage HGH system.
For controlling the basket a simple steppermotor and driver would suffice than depending on the total weight you have to move up and down.
So actually you are implementing one axis of a CNC machine with two guidance rails.
Or perhaps since it is a hobby system and I only need one board, just turn off the heating and wait for it to cool. Suggestions welcome!
Would not recommend that, it could take an hour too cool down and I am afraid a lot of components can not stand 230oC for more than a few minutes (see datasheets) making it practically unusable. Than also the solderjoint will deteriorate since it is supposed to be cooled down, it might make it brittle since the flux has gone.
PDF attached, what do you make of this.. Is this a marketing thing, or is this for real.
Probably real but don't forget these are industries running 24/7 in the week, you should ask yourself how often will you be using this system and how much will you then loose to evaporation. If you make the tank high enough and add cooling above than you should even have to worry less.
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Now I'm trying to think about how to raise the board gently when potentially the balls are still liquid.
I think your biggest challenge here is a smooth motion without rocking and too fast accelaration/deceleration.
A quick though about rocking/shaking is to use guidance rails like CNC machines do.
They are now so accurate the backlash is within 0,001 mm even when milling steel so not a problem for your system.
You have a lot of choice, for instance IGUS DryLin Linear Guide or even HIWIN Carriage HGH system.
For controlling the basket a simple steppermotor and driver would suffice than depending on the total weight you have to move up and down.
So actually you are implementing one axis of a CNC machine with two guidance rails.
I was thinking this too, I have already have some linear guides and steppers waiting to go. My only problem would be contamination of the fluid with the factory-shipped lubricants, I will have to give them a really good clean beforehand. It would probably be chain driven (too hot for belts I think) as well so that will need to be cleaned too. I do have a spare short ballscrew floating around here somewhere though...
Perfluorocarbons are used as lubricants anyway, so should be no problem running them without lubricant.
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Another thing to test is if the carriage will expand the same amount as the guidancerail it self otherwise it could get stuck at higher temperatures.
A CNC guidance rail is so sturdy that you could let it end well above the higher temperature and just extend the platform. The picture with the external (seperate) lifting system of one of the previous pages comes into mind.
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Another thing to test is if the carriage will expand the same amount as the guidancerail it self otherwise it could get stuck at higher temperatures.
A CNC guidance rail is so sturdy that you could let it end well above the higher temperature and just extend the platform. The picture with the external (seperate) lifting system of one of the previous pages comes into mind.
It's like you're reading my mind! I was just trying to work out if the heat would conduct through the rail and carriage enough to make the problem negligable. I think it would make for a much simpler build if you didn't have to make any extensions. The problem is that this is looking like an all-metal construction as good borosilicate glass is very expensive in large internal diameters, and I think it would be good if we could devise something that the average hobbyist at home could build (aka without a cold saw and milling machine)
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Ok, but to play devils advocate here:
Can anyone shed any light on why fluid viscosity really matters in a batch oven? I can't think of anything.
Lower viscosity - better run-off from the PCB?
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lower viscosity - better heat transfer to the center of large FBGAs
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Ok, but to play devils advocate here:
Can anyone shed any light on why fluid viscosity really matters in a batch oven? I can't think of anything.
Lower viscosity - better run-off from the PCB?
Yes, this is about the only sensible thing that I could come up with. But I think this is again less of a problem when you are doing single boards in a slow batch oven. Inline systems sure; of course you don't want the fluid to be taken away by conveyer. I had a look, and both fluids have almost identical surface tension, so given how inert this stuff is (it doesn't really dissove) I'm sure it will be just as easy to pour off either one.
lower viscosity - better heat transfer to the center of large FBGAs
I'm not sure this is correct; we're talking about the viscosity of the fluid being heated, not the viscosity of the vapour. Although they probably will be related. As a reference, the HT series, which is more viscous, still has a kinematic viscosity of 10 times less than olive oil. And ~3 times more than tap water at room temperature. Of course this will decrease with heating.
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heat is transferred to the parts by a liquid phase, not a gas. the vapor condenses on the surface, so the board is entirely immersed in liquid, less than 1mm thick. when the peak temperature is reached, the vapor stops turning to liquid. so vapor itself does not do anything to the components.
see the presentation: (the slide decks on this channel are extremely detailed)
Vapor Phase Fluids and Process Control (https://www.youtube.com/watch?v=biEKx3Xt8d0#)
especially the point on "low surface tension". Viscosity and surface tension are related, although the relationship is different for different types of materials.
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heat is transferred to the parts by a liquid phase, not a gas. the vapor condenses on the surface, so the board is entirely immersed in liquid, less than 1mm thick. when the peak temperature is reached, the vapor stops turning to liquid. so vapor itself does not do anything to the components.
see the presentation: (the slide decks on this channel are extremely detailed)
...
especially the point on "low surface tension". Viscosity and surface tension are related, although the relationship is different for different types of materials.
I think you have perhaps misunderstood my point, because although the video mentions that surface tension is important, the measured surface tension of both the LS and HT fluids basically are identical. So regardless of how important that particular quality is, there is no difference between LS and HT. In my understanding (which could be totally wrong! my chemistry is a bit rusty), with high surface tension the condensed fluid would be more likely to stick in droplets on various hot parts of the PCB in the same way that you see water "beading" on hydrophobic surfaces. These droplets would absorb some of the energy of the phase transition in their own thermal mass, thus making the transfer of heat into the board slower. You want the low surface tension stuff so that the fluid will be more likely to drip off and flow rather than stick together, leaving a higher thermal gradient to encourage the phase transition.
The viscosity of the HT fluid is likely much lower than water at ~230C, and washing boards in water does not ever seem to be a problem in terms of its viscosity.
I also don't think it is as simple as saying that the fluid does all the work. The vapour carries the potential energy via its latent heat of vapourisation. When the vapour comes into contact with the cold board, the board will absorb the heat as a counterpart to the phenomena that allows the vapour to transition to a liquid phase (in a pretty yin-yang kind of way). So it is really neither the vapour nor the liquid that does the work, but the action of transitioning between the two which releases the heat. This transition is prevented when the board is the same temperature as the liquid as the vapour cannot deposit it's energy anywhere in order to return to the liquid phase. I think heating merely from the liquid being hot would be much less significant, and could almost to the point of being negligable.
If you look at the lovely wikipedia picture I found (attached, taken from http://en.wikipedia.org/wiki/File:Energy_thru_phase_changes.png (http://en.wikipedia.org/wiki/File:Energy_thru_phase_changes.png)) you can see that for water, it takes only 8kJ to reach the phase transition zone, but then it needs a whopping 40kJ to actually turn into steam. So if we were using water as the vapour medium, even if the condensed liquid cooled all the way to 0C, it would only deposit 8kJ of energy (ignoring the phase transition energy). However, if the water vapour used the thermal gradient of a cold board to condense, it would heat the board 5 times faster, even if the water only cooled by 0.1C before dripping off the board. So it is the transition itself which is important
Thank you for sharing the video, it was very interesting. I will have a dig through his channel later.
And just to reiterate, I'm not arguing that HT is better in performance, I'm just arguing that it is perhaps better in performance/$ for a small batch oven. It is double the price after all.
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I think you are focused too much on the cost of the fluid. it could cost 10 times as much and it would still be less than the cost of engineering a proper heat loop, cooling system, mechanical elevator, vapor detector, control system, user interface, and chassis.
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I think you are focused too much on the cost of the fluid. it could cost 10 times as much and it would still be less than the cost of engineering a proper heat loop, cooling system, mechanical elevator, vapor detector, control system, user interface, and chassis.
I disagree. This is on my own time, so time isn't worth all that much ;) and I think I already have most of the physical bits already (including linear bearings, motor drivers, chains, many devkits I can use as the controller, thermocouples, induction heating plates). So the major outlay for me will be the fluid, especially given that I'll probably mess up and lose some. This isn't a 24/7 machine, it just has to work while I'm looking after it. Even the 3M system which they used to solder expensive Intel CPUs is just a dumb heater, plus some water flowing around a big test tube.
Plus, I think it would be more applicable to others using the cheaper fluid.
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Well, don't let me be the bearer of bad news :-X
One last video as cautionary tale:
EE400D Vapor Phase Soldering (https://www.youtube.com/watch?v=WhymoY3ZHjY#ws)
Notice how vapor is pouring out of their setup. This means that the heat input is in excess of what is required for the small board they are reflowing. It causes tombstoning, and look at that BGA |O
this is what VPR was like in the 60s when it was abandoned.
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Notice how vapor is pouring out of their setup. This means that the heat input is in excess of what is required for the small board they are reflowing. It causes tombstoning, and look at that BGA |O
this is what VPR was like in the 60s when it was abandoned.
If i saw the presentation on the previous page they measure the temp on three vertikal places and lower the board when there is no vapour yet (so the Galden temp is around 200) than apply the extra heat and control it so the temp is following the reflow profile. That is how i intertreted it.
The video you showed is amateur time no smooth operating elevation, no temperature control what I can see and they are boiling the Galden even way before the pcb is lowered.
And even worse no lid to contain the vapour to let it come in contact with the coolong area and liquidize back.
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Notice how vapor is pouring out of their setup. This means that the heat input is in excess of what is required for the small board they are reflowing. It causes tombstoning, and look at that BGA |O
this is what VPR was like in the 60s when it was abandoned.
If i saw the presentation on the previous page they measure the temp on three vertikal places and lower the board when there is no vapour yet (so the Galden temp is around 200) than apply the extra heat and control it so the temp is following the reflow profile. That is how i intertreted it.
The video you showed is amateur time no smooth operating elevation, no temperature control what I can see and they are boiling the Galden even way before the pcb is lowered.
And even worse no lid to contain the vapour to let it come in contact with the coolong area and liquidize back.
And if you find the long version of the Video,you'll find that they actually poured water into the tank. ( why we don't know, but these were engineering students, anything is possible when you know everything ). Galden vapour is transparent, you can't see it, so that vapour is probably boring old H2O.
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Some more data, that i was able to obtain tells me that;
The Distillation spec range of the HT230.
10% > 210C, 90% < 250
Compared to the LS which is
10% < 222, 90% < 235
The viscosity of the HT is between 3 and 7, and for the LS its 5-6 cSt.
The base material of the two products is the same thing, its how it is processed.
I am in a very interesting discusion with a supplier who can further distill the HT230,, and bring the spec very close to that of the LS-230. 7kg of this 'tweaked' product, will be around $1000 for 7kg, which compares favourably to a the $1400 or so for 5kg of LS-230. I'm now very tempted to proceed on this.
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And if you find the long version of the Video,you'll find that they actually poured water into the tank.
That does sound awfull, mixing a liquid with a boiling point of 230oC with one that has a boiling point of 100oC is rediculous, so scrap that video as any serious source of information.
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And if you find the long version of the Video,you'll find that they actually poured water into the tank.
That does sound awfull, mixing a liquid with a boiling point of 230oC with one that has a boiling point of 100oC is rediculous, so scrap that video as any serious source of information.
Heres the long version.
https://www.youtube.com/watch?v=FJvLBmhPMx0 (https://www.youtube.com/watch?v=FJvLBmhPMx0)
I love the combination of AC mains, very loose wire, water, and working out the front of the garage.. What do you make of the platform. Its awesome. Listen at 1:20.. " that could be all you galden esacping.. I hope not.. Do you want to put a bit of water in there? "
I wonder if what they were trying to create some kind of 'cover layer'?
I would'nt completely right off this video. I think these guys should get some points for trying. And they did actually get something soldered. I'm really curious to know what the motivation for the water was..
@6:43.. what the heck was that.. Did you kick it.
@7:18.. I better help that stepper motor.
@7:47.. oh "f...k" it soldered.
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Interesting thread guys, hope it all comes together for you.
As I see it a deep vessel will be very important to contain and not waste vapour.
This is presumably where the pre-heating comes in to play with the different temp zones as you go deeper.
Is there agreement that there should be a cooled lid?
Had a look at the info linked and it's unclear how much vapour would be produced per say each litre of Galden. :-//
Wondered if a circular domestic stove element would work as a heater?
Say a 6" one with it's thermostat, real easy I think and they're only ~8mm thick plus bracket for a total say 15mm. Should easy cover it with a litre.
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Listen at 1:20.. " that could be all you galden esacping.. I hope not.. Do you want to put a bit of water in there? "
I wonder if what they were trying to create some kind of 'cover layer'?
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I'm really curious to know what the motivation for the water was..
too much credit, if they were afraid that their costly Galden was evaporating their thought probably was too cool down the fluid so it stopped boiling/evaporating, hence add some cold fluid, like water.
What they should have done was to turn the temperature control down and rework their control loop. But hey that needs some time to think. :palm:
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Interesting thread guys, hope it all comes together for you.
As I see it a deep vessel will be very important to contain and not waste vapour.
This is presumably where the pre-heating comes in to play with the different temp zones as you go deeper.
Is there agreement that there should be a cooled lid?
Had a look at the info linked and it's unclear how much vapour would be produced per say each litre of Galden. :-//
Wondered if a circular domestic stove element would work as a heater?
Say a 6" one with it's thermostat, real easy I think and they're only ~8mm thick plus bracket for a total say 15mm. Should easy cover it with a litre.
I think we are all in agreement that there needs to be some cooling at the top. Whether that is a cooled lid, cooled sides or something else (cold mesh perhaps?) I think still needs to be determined.
The amount of vapour you get will somewhat be a function of the spatial distribution of heating and injected energy, as well as possibly your own individual batch of fluid. So I'm not sure it is easy to just give an amount of vapour per litre. I think the more useful characteristic is the vapour "height", which seems mostly to be controlled by temperature/injected energy. The better you can control the vapour height, the better your oven will be.
I'm sure many sorts of heaters would work, including the one you mentioned. It seems to be more a problem of controlling the fluid loss while still getting adequate vapourisation.
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I think the more useful characteristic is the vapour "height", which seems mostly to be controlled by temperature/injected energy. The better you can control the vapour height, the better your oven will be.
That might be the reason for the three level temperature sensoring, might be necessary for a good level control indication.
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Ok, so I've been reading the manual of the weller WAM3000 very carefully, and here is my guess at how it works. Also, nailed down some parameters I think would be reasonable to aim for. See attached for the diagram taken from the weller manual here: http://www.egmont.com.pl/cooper/instrukcje/OI_WAM3000_GB.pdf (http://www.egmont.com.pl/cooper/instrukcje/OI_WAM3000_GB.pdf)
The weller machine supports a 300x300x55mm board. I'm guessing the air space cross section in the chamber is maybe 350x350mm ? It also supports a load of maximum 1kg. I have some medium sized steppers lying around from a different project which are rated at about ~3 Nm, so with a small sprocket and chain drive it should easily be able to lift 1kg+1kg platform. This seems like a pretty good target load.
The machine drawing appears to be to scale (all of the external dimension ratios match the machine specs). From this, I have the following very rough measurements:
Full chamber (including gated zone but not including fluid container): 360mm high, 350mm square
Gated location: 120mm from the top of the fluid container
Fluid container: 40mm high, 200mm square
First, you have three sensors. I'm going to assume these are thermocouples, given that the vapour is optically transparent and is extremely chemically inert. The right thermocouple should hopefully have a fast enough response time. (Maybe using those fairly recent 4x4 thermopiles or something could be interesting here. melexis is the company iirc?). Level 1 is closest to the heater at the bottom.
Here are the basic steps:
- Heat the vapour phase fluid until Level 1 reaches the defined preheat temperature
- Open the top door, put your populated board onto a mesh platform. Close the door and press go
- The board is lowered approximately to the level 2 sensor and the gate above the level 3 sensor is closed
- Heat is applied to the fluid until Level 3 reaches the defined finish temperature. The vapour will not rise that high unless the PCB is unable to absorb any more heat; this means that basically condensation has stopped and the solder should be fully reflowed
- Heat is reduced and external cooling fans are turned on. After level 2 drops below a defined temperature, the gate will be opened and the mesh platform will be lifted
- Enjoy your freshly soldered PCB!
PS while I'm not saying anyone should throw out your soldering irons, have you seen the price of the high end weller/pace/ersa/metcal gear? It makes the fluid look very cheap in comparison! ;) I think that an entire DIY vapour phase setup (with fluid) would cost less than one of my weller stations, and I have two of them!
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So, i think we have a good solution for our vapour fluid. ( further distilled Galden HT230 ). Time to move on a little.
Theres a lot of variables here, that we don't have a good handle on. but some guidance from the commercial machinese is helpful.
Heres my thoughts on the other topics.
(a) the Weller and that other machine we saw, both suggest using about 1kg of Fluid in their machines, Thats only about 600ml. My suspision is that you don't need much fluid to make quite a lot of vapour.
(b) the commercial machines all seem to have a small "well" in the bottom of their tanks, you don't need to cover the entire base
(c) Heating almost certainly should be by some kind of external heater rather than an immersion one. Plenty of options there, and it really needs to be closed loop control system. We want to provide enough energy, but not too much. For experimentation purposes I'm thinking that it will be very useful to measure temp at several locations.. I'm thinking
- in the fluid to be boiled
- on a aluminium block that can be raised and lowered, this in many ways can be used to simulate your 'load'.
- Some sensors further above the vapour.
My feeling is that if we cafefully control the heating, then vapor loss is going to be minimal. Look at this video ( https://www.youtube.com/watch?v=aUAZkan6jz4 (https://www.youtube.com/watch?v=aUAZkan6jz4) ). There is nothing elaborate about their 'tower'.
Time to stop talking and order some fluid and get started.
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So, i think we have a good solution for our vapour fluid. ( further distilled Galden HT230 ). Time to move on a little.
Theres a lot of variables here, that we don't have a good handle on. but some guidance from the commercial machinese is helpful.
Heres my thoughts on the other topics.
(a) the Weller and that other machine we saw, both suggest using about 1kg of Fluid in their machines, Thats only about 600ml. My suspision is that you don't need much fluid to make quite a lot of vapour.
(b) the commercial machines all seem to have a small "well" in the bottom of their tanks, you don't need to cover the entire base
(c) Heating almost certainly should be by some kind of external heater rather than an immersion one. Plenty of options there, and it really needs to be closed loop control system. We want to provide enough energy, but not too much. For experimentation purposes I'm thinking that it will be very useful to measure temp at several locations.. I'm thinking
- in the fluid to be boiled
- on a aluminium block that can be raised and lowered, this in many ways can be used to simulate your 'load'.
- Some sensors further above the vapour.
My feeling is that if we cafefully control the heating, then vapor loss is going to be minimal. Look at this video ( https://www.youtube.com/watch?v=aUAZkan6jz4 (https://www.youtube.com/watch?v=aUAZkan6jz4) ). There is nothing elaborate about their 'tower'.
Time to stop talking and order some fluid and get started.
The weller has a sensor in the fluid as well. And to simulate your load, why not just get an already soldered PCB?
I am going to try 1/4" ASTM420 stainless ball bearings in a pyrex beaker (currently in the mail) and an induction hot plate; I think this alloy will work. I'm also trying to get a board manufactured with some 0.5mm pitch BGAs for testing, but that's proving to be quite difficult (in fact, at this stage one board would cost more than 1kg of galden due to the 3/3mil traces required).
Also, from that video:
chain driven lift: check
linear guides: check
guides don't extend all the way into the fluid, but get close: check
Unfortunately though I am away from home for a month, so no playing with toys for me. :'(
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The weller has a sensor in the fluid as well. And to simulate your load, why not just get an already soldered PCB?
because i'll be able to easily make a nice fitting for a thermocouple and it will be completely consistent.
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Ok, so I've been reading the manual of the weller WAM3000 very carefully, and here is my guess at how it works.
I am with you untill the level the board is lowered to.
My gut feeling (nothing more so another guess) tells me that the three sensors are covering the entire heating volume so the lowest sensor is the bottom and the highest sensor is the top, so the middle sensor is the middle and that should be the location of the pcb (my guess).
So if the highest sensor reaches the set temperature or above all power should be cut because vapor is then escaping the zone, just my guess to it if I should build it.
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Ok, so I've been reading the manual of the weller WAM3000 very carefully, and here is my guess at how it works.
I am with you untill the level the board is lowered to.
My gut feeling (nothing more so another guess) tells me that the three sensors are covering the entire heating volume so the lowest sensor is the bottom and the highest sensor is the top, so the middle sensor is the middle and that should be the location of the pcb (my guess).
So if the highest sensor reaches the set temperature or above all power should be cut because vapor is then escaping the zone, just my guess to it if I should build it.
Hrm, I can see your point, but I would worry that the second sensor has a much faster thermal time constant than the PCB itself, and would report being fully heated well before the PCB is. The sensor is mounted in the wall remember, not on the PCB.
I think I read somewhere (I can't find it now any more) that asscon uses the third level as the end-of-soldering sensor. And I suppose it isn't possible to lose any fluid or vapour if the gate is properly sealed.
But of course, both of these things would be easy to verify with a real system, so it should just be a case of trying them both. Thanks for your input.
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Hrm, I can see your point, but I would worry that the second sensor has a much faster thermal time constant than the PCB itself, and would report being fully heated well before the PCB is. The sensor is mounted in the wall remember, not on the PCB.
And you wondered why i wanted to put a thermal sensor in a block of alluminum. To give it some thermal mass.
I'm also pretty convinced that there is minimal need to actually have the shutter system. I'm sure that the vapour height can be controlled pretty well. and that in a reasonably well controlled system the vapour won't escape the tank anyway. The systems with shutters are doing it for a different reason. They are blowing air across them, which is for cooling, and from what i see they are looking to cool the boards quickly for inline systems. for doing low voume batch work, this doe'snt seem to be a requirement.
Control here, is critical.
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Hrm, I can see your point, but I would worry that the second sensor has a much faster thermal time constant than the PCB itself, and would report being fully heated well before the PCB is. The sensor is mounted in the wall remember, not on the PCB.
And you wondered why i wanted to put a thermal sensor in a block of alluminum. To give it some thermal mass.
I'm also pretty convinced that there is minimal need to actually have the shutter system. I'm sure that the vapour height can be controlled pretty well. and that in a reasonably well controlled system the vapour won't escape the tank anyway. The systems with shutters are doing it for a different reason. They are blowing air across them, which is for cooling, and from what i see they are looking to cool the boards quickly for inline systems. for doing low voume batch work, this doe'snt seem to be a requirement.
Control here, is critical.
Actually, I was wondering why because aluminium has far too good thermal conductivity. Fibreglass has a thermal conductivity of something like 0.05 while aluminium has a conductivity of ~200 W/(m.K). So given this large difference (X 4000) you could possibly tune your control loops for the wrong parameters, and you might not be able to find hotspots in the oven because the aluminium will hide that.
Why fake the load if you can just have a real one? It is a common thing to mount thermocouples on PCBs.
I think the gate on the weller machine is mostly for safety. It isn't an inline system.
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Even the inline vapor-phase machines aren't continuous, they are more like a buffered batch system.
The reflow profile should control both the heating and cooling steps for uniformity and to save the components.
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Sorry to jumping in without having read all those previous pages in details.
Looks a cool project, I´m wondering if it would be possible to get a cheap liquid and change the boiling point by changing the (vapor) pressure in the chamber:
Form Wiki:
(http://upload.wikimedia.org/wikipedia/commons/9/96/Vapor_Pressure_Chart.png)
http://en.wikipedia.org/wiki/Vapor_pressure (http://en.wikipedia.org/wiki/Vapor_pressure)
Take for example mineral oil:
http://www.sciencelab.com/msds.php?msdsId=9927364 (http://www.sciencelab.com/msds.php?msdsId=9927364)
Boiling Point:310°C (590°F)
Vapor Pressure:<0.1 kPa (@ 20°C)
so if we create a negative pressure in the chamber (below 1 bar absolute) then it should be possible to get the 230°C boiling point or whatever you want. By then rising the pressure to the atmosferic one the vapor will turn into liquid and ready to take the final product out.
Surely there is a big elephant I am overlooking...
PS: OK, I got it. The solder melting point depend also on ambient pressure... another idea in the garbage can?
PS2: Anyone knows the solder melting point graph temperature vs pressure? I couldn´t find nothing on the www.
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Looks a cool project, I´m wondering if it would be possible to get a cheap liquid and change the boiling point by changing the (vapor) pressure in the chamber:
You do not need to change the boiling point of the liquid, you need to have the temperature at 230oC for the solderpaste to melt :palm:
If I vacuum soup or water in a bag in my vacuummachine for instance it starts boiling at room temperature, but if there was an egg inside the soup it would not get hard boiled not even after an hour.
So you approach this the wrong way around I am afraid.
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Looks a cool project, I´m wondering if it would be possible to get a cheap liquid and change the boiling point by changing the (vapor) pressure in the chamber:
You do not need to change the boiling point of the liquid, you need to have the temperature at 230oC for the solderpaste to melt :palm:
If I vacuum soup or water in a bag in my vacuummachine for instance it starts boiling at room temperature, but if there was an egg inside the soup it would not get hard boiled not even after an hour.
So you approach this the wrong way around I am afraid.
You could use a pressure pot and a liquid with lower than 230C boiling point. Increasing the pressure increases the boiling point.
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If I vacuum soup or water in a bag in my vacuummachine for instance it starts boiling at room temperature, but if there was an egg inside the soup it would not get hard boiled not even after an hour.
So you approach this the wrong way around I am afraid.
Uh? If the boiling point if bigger than 230 C (mineral oil) than you need to lower the pressure.
I am sure if you read again my post you will understand. If you have any questions I am glad to help
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You'd have to find something chemically inert, because evaporating flammable liquids is a great way to get an explosion. But realistically I think all the added complications of containing a lower (or higher) pressure make it a far worse alternative than just paying for the inert, non-toxic, ambient pressure stuff. The price will come down the more popular it gets, and with a suitable apparatus you won't need much of it nor will you lose any during operation.
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Sorry to jumping in without having read all those previous pages in details.
Looks a cool project, I´m wondering if it would be possible to get a cheap liquid and change the boiling point by changing the (vapor) pressure in the chamber:
Surely there is a big elephant I am overlooking...
Yep. SAFETY
This WHOLE thread is worthy of reading and this nicely sums up what is required:
You'd have to find something chemically inert, because evaporating flammable liquids is a great way to get an explosion. But realistically I think all the added complications of containing a lower (or higher) pressure make it a far worse alternative than just paying for the inert, non-toxic, ambient pressure stuff.
When I wanted to get into SMD, a rework station cost more than a litre of Galden. :palm:
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Jeremy,
Apropos the stainless steel balls.. there aretwo types of steel generally speaking .. austenitic and martensitic. The type is dependent on the manufacturing process how these metalurgical properties are developed ( crystaline structure which affects how the magnetic domains are established and formed.
This also applies to stainless steel. Some alloys are magnetic others are not.
300 series alloys are not magnetic where as 400 series alloys of stainless steel are.
On the question of temperature measurement: addition of aluminium heat sink to the thermocouple would only detract from the quality of temperature measurement and subsequent tightness of the control loop.
Temperature of the vapour cloud is unimportant so long as the cloud exists, gets "consumed" and is replenished from the boiling liquid.
Essentially the only reasonone would measure the temperature of the space where the cloud is to form is to confirm it has formed.
As the fluid is heated the volume of the cloud increases but it's temperature remains constant as all the energy is consumed in evaporating the fluid.
So simply use the measurement of temperature to confirm the probe is immersed in the cloud .
With a batch oven a tall batch oven the cloud needs to be stratified and the way to do it is to set up energy sinks and sources which would contain the cloud; namely a heater and a cooling jacket which will place a lid on top of the cloud.
The cooling jacket will cause vapour to condense and drip back into the fluid reservoir. Vapour pressure will tend to level off any un evenness in the vapour layer by ensuring a continuous interface between the vapour jacket and the cooling jacket.
This equilibrium will ensure a uniform blanket of vapour into which the PCB needs to be immersed.
The space above the vapour layer will be at increased temperature through natural convection of air and it is this volume above the vapour that is used as preheat and cooling zone.
This is my understanding and I shall be making an oven in line with this understanding.
I have made some enquiries with a local sheet metal shop and stainless steel hardware suppliers. My expectation is to start spending money during the coming weeks.
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Jeremy,
Apropos the stainless steel balls.. there aretwo types of steel generally speaking .. austenitic and martensitic. The type is dependent on the manufacturing process how these metalurgical properties are developed ( crystaline structure which affects how the magnetic domains are established and formed.
This also applies to stainless steel. Some alloys are magnetic others are not.
300 series alloys are not magnetic where as 400 series alloys of stainless steel are.
Yep, I made sure to get 420 stainless and from an amazon supplier so at least I can try to get my money back (all $5 :P ) if they ship me 303 or something.
Please keep us updated on your progress. I intend to do something similar when I get the chance, but I've not really dealt with much sheet metal before.
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Jeremy,
On the question of temperature measurement: addition of aluminium heat sink to the thermocouple would only detract from the quality of temperature measurement and subsequent tightness of the control loop.
the sensor i was thinking of putting in the aluminum would be on the carrier that was carrying the board. I'd also have fixed sensors in the tank, and they would be set up to have minimal thermal 'interia'. what i was trying to achieve was something that "mimiced" a pcb that will have to heat up ( which takes time ). It might be ( and not sure yet ) useful for helping to determine when the pcb has reached melting temp and also to help establish when it has cooled enough to be able to safely move it. ( and cool it rapidly with air ).. Don't want to be moving it too quickly when its still molten.
I'm thinking of of using some linear guides ( http://us.misumi-ec.com/vona2/detail/110301962560/?Inch=0 (http://us.misumi-ec.com/vona2/detail/110301962560/?Inch=0) Misumi stuff is not overly expensive, not as cheap as flea-bay, but it is reliable, and they have a million options and cad drawings. ) for the carrier inside the tank. That will require a reasonablely careful approach to ensure they are all runnign parallel.
About to order my "modified" HT230. ( its HT230, thats been reprocessed ). As for loss, i was talking with a guy who's got a commercial machine and he has done over 20,000 boards in theres, and he thinks, they might have used 3/4 of a 5kg bottle. So, provided you don't lose the stuff, you'll need very very little over time.
Seems also that it might be good to have a "well" in the middle of the tank, to heat the liquid in, rather than try to heat the entire base of the tank.
I'm looking to do something that i can put a 250 x 350 mm sized board / panel in.
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i mole of any liquid gives 22.4 litres of gas at normal temperature and pressure, so with a molecular weight of about 80? just a guess here, then 80 gms gives 22.4 litres of vapour. That should help you size how much you need, you also need to consider that the heating element needs to stay immersed in the liquid portion.
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MK..
nicely pointed out...
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Is stainless steel really a requirement?
I mean if fluid is inert it ought not contribute to corrosion process in any way.
Why does it need to be stainless steel why not ordinary galvanized sheet metal ?
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Can't this type of reflow be achieved using less expensive liquids? For example, using a pressure cooker to increase the vapors temperature.
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A pressure vessel brings in problems of its own.
Licensing of operator and inspection of equipment come to mind immediately.
Trying to achieve the thermal profile I suspect becomes a bit more complicated.
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A pressure vessel brings in problems of its own.
Licensing of operator and inspection of equipment come to mind immediately.
Trying to achieve the thermal profile I suspect becomes a bit more complicated.
I was thinking of a home setting for hobby purposes. Profile may be controlled by controlling the pressure in addition to the heat and possibly using solder paste with lower melting temperature.
Edit: Glycerin for example has a sea level boiling temperature of 554F,
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Can't this type of reflow be achieved using less expensive liquids?
We'd all like to know that too, but how they might behave at elevated temperatures is the unknown. :-//
Contamination of the reflow MUST be of primary concern would you not think?
Then there is the interaction with any componentry also to consider.
Inert, non-toxic tailored reflow fluids seem the best option to me.
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Can't this type of reflow be achieved using less expensive liquids?
I would look at a convection oven using circulating hot air. Air is cheap and easily obtained, and the circulation currents lead to even heating and good heat transfer.
A possible design could include an electric hot air gun as a heat source and a triac dimmer for temperature control. The hot air gun comes with its own fan, so you only need to put together a suitable insulated enclosure with a window and some suitable baffles for good circulation. The temperature sensor could be placed in the exhaust port and measure the air temperature leaving the oven.
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Can't this type of reflow be achieved using less expensive liquids?
I would look at a convection oven using circulating hot air. Air is cheap and easily obtained, and the circulation currents lead to even heating and good heat transfer.
A possible design could include an electric hot air gun as a heat source and a triac dimmer for temperature control. The hot air gun comes with its own fan, so you only need to put together a suitable insulated enclosure with a window and some suitable baffles for good circulation. The temperature sensor could be placed in the exhaust port and measure the air temperature leaving the oven.
Sorry Ian, but have you read the whole thread?
One of the benefits of VP is the inert atmosphere of the vapour, the main reason to investigate this technology.
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Sorry Ian, but have you read the whole thread?
One of the benefits of VP is the inert atmosphere of the vapour, the main reason to investigate this technology.
I understand that, but I have not seen the argument that the inert atmosphere is important. Is it common to use an inert atmosphere in industrial reflow soldering processes today? If soldering today was done in an argon atmosphere I would see the point, but I'm not sure that is the case. It's my understanding that the solder flux forms a protective film between the air and the molten solder and this is a sufficient barrier to keep oxygen away.
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using a nitrogen blanket in an inline reflow machine seems fairly common.
There seem to be some untrue rumors about it going around, though:
http://blogs.indium.com/blog/semiconductor-and-power-semi-assembly/dispelling-10-myths-about-nitrogen-reflow-part-i (http://blogs.indium.com/blog/semiconductor-and-power-semi-assembly/dispelling-10-myths-about-nitrogen-reflow-part-i)
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About 20 years ago I sold the first nitrogen atmosphere wave soldering machine in Australia.
You could see the solder pot surface remain dross free as the oxygen level inside the process tunnel went down. Minimum flux was required to get good solder joints.
In fact the difference in density between flux and flux solvent was imperceptible attesting to the low solids flux.
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Is stainless steel really a requirement?
I mean if fluid is inert it ought not contribute to corrosion process in any way.
Why does it need to be stainless steel why not ordinary galvanized sheet metal ?
I don't think so. Most cooking ovens I have seen are not made of stainless, so I don't see why galvanized metal would be a problem. Much easier to weld shut too.
Zapta: I think at higher pressures you will change the melting point of the solder. Also, you could possibly force the fluid into the fr4 or other parts.
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Actually Ian has a fairly good point I think.
If you have a large vessel with at the bottom a controlled oven heated 230o
C area filled with Argon gass (which is heavier than air so will stay at the bottom) it would still be a matter of slowly lowering the pcb inside the area till the temp profile is correct.
Only problem I see is that hot air rises up so you have less controlled heating profile unless you let the pcb slide in from aside instead of above but then you have chance of loosing Argon.
We need a mechanical engineer here to sort this out :)
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Actually Ian has a fairly good point I think.
If you have a large vessel with at the bottom a controlled oven heated 230o
C area filled with Argon gass (which is heavier than air so will stay at the bottom) it would still be a matter of slowly lowering the pcb inside the area till the temp profile is correct.
Only problem I see is that hot air rises up so you have less controlled heating profile unless you let the pcb slide in from aside instead of above but then you have chance of loosing Argon.
We need a mechanical engineer here to sort this out :)
For a hobbyist to buy and keep an Argon supply on hand will cost more than the litre of Galden.
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For a hobbyist to buy and keep an Argon supply on hand will cost more than the litre of Galden.
You can get disposable cylinders of argon for welding - about GBP17 in the UK
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Air, density about 1.2 Kg m3, Argon about 1.6 Kg m3, galden ht230 has a molecular weight of about 1000, so ~26kg per m3
www.g-werner.at/de/downloads/solvay_solexis_galden.pdf (http://www.g-werner.at/de/downloads/solvay_solexis_galden.pdf)
I think the argon will be superfluous.
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For a hobbyist to buy and keep an Argon supply on hand will cost more than the litre of Galden.
I have a 5 litre tank for my wine hobby ;)
If I remember correctly (couple of years back) you buy the tank for around 100 euro's and next time only pay the refills (you exchange the cylinder for a filled one) costing 18 euro's or something like that. Only problem is safety if it leaks in a closed environment there will be no air to breath. But than if you have a small cylinder this would not pose a big problem.
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Air, density about 1.2 Kg m3, Argon about 1.6 Kg m3, galden ht230 has a molecular weight of about 1000, so ~26kg per m3
I think the argon will be superfluous.
What do you exactly mean, superfluous? :-// Google translation says "not necessary", but the argon prevents the oxydation if you use simple hot air reflow and do not use galden. Yes if you use galden Argon is useless.
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For a hobbyist to buy and keep an Argon supply on hand will cost more than the litre of Galden.
Good to see that not everybody gets raped on industrial gas pricing like we do in NZ.
Bottle hireage ~$120/year
Re-fillable bottle purchase $500 up
2 m3 fill ~$80
Hence the reason behind my statement
Air, density about 1.2 Kg m3, Argon about 1.6 Kg m3, galden ht230 has a molecular weight of about 1000, so ~26kg per m3
www.g-werner.at/de/downloads/solvay_solexis_galden.pdf (http://www.g-werner.at/de/downloads/solvay_solexis_galden.pdf)
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So what is an educated estimate of the m3 of vapour from 500ml of Galden?
Cause you can't see the stuff, how big might a suitable vessel need to be?
Or is this of little concern as it will be ALL temp controlled?
From the datasheet linked above:
The process is extremely fast and efficient since the
heat transfer coefficient of vapor condensation is
about ten times (10x) faster than hot air and about
eight times (8x) faster than infra red heat.
Doesn't that fascinate you, it does me.
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Air, density about 1.2 Kg m3, Argon about 1.6 Kg m3, galden ht230 has a molecular weight of about 1000, so ~26kg per m3
I think the argon will be superfluous.
What do you exactly mean, superfluous? :-// Google translation says "not necessary", but the argon prevents the oxydation if you use simple hot air reflow and do not use galden. Yes if you use galden Argon is useless.
I assumed people wanted to use Argon and Galden, as argon by itself will not have enough thermal capacity/conductivity to do the job fast enough.
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For a hobbyist to buy and keep an Argon supply on hand will cost more than the litre of Galden.
Good to see that not everybody gets raped on industrial gas pricing like we do in NZ.
Bottle hireage ~$120/year
Re-fillable bottle purchase $500 up
2 m3 fill ~$80
Hence the reason behind my statement
Air, density about 1.2 Kg m3, Argon about 1.6 Kg m3, galden ht230 has a molecular weight of about 1000, so ~26kg per m3
www.g-werner.at/de/downloads/solvay_solexis_galden.pdf (http://www.g-werner.at/de/downloads/solvay_solexis_galden.pdf)
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So what is an educated estimate of the m3 of vapour from 500ml of Galden?
Cause you can't see the stuff, how big might a suitable vessel need to be?
Or is this of little concern as it will be ALL temp controlled?
From the datasheet linked above:
The process is extremely fast and efficient since the
heat transfer coefficient of vapor condensation is
about ten times (10x) faster than hot air and about
eight times (8x) faster than infra red heat.
Doesn't that fascinate you, it does me.
500 ml of galden at 230 centigrade will be about 33 litres or just a bit more, then you need to allow a reasonable volume on top to allow for the stirred layer not to lose any galden, as it costs quite a lot, down to your design skills to keep the galden where you need it.
MK
edited because I forgot to allow for the high specific gravity of galden.
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Just throwing it out there, but perhaps brake fluid will work?
dot 4 has a 230C melting point, but is made of glycols so is likely flammable however dot 5 is silicone based and has a vapor point of 260C. I have no idea what else is in there though so I wouldn't want to breath the vapors, but perhaps another generally available silicone will work? Take appropriate precautions if you try this of course.
John
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As a starter for 10 points, I'm going to do my designed based on the following;
My tank size is going to be 400 x 300mm, and i figure i want a vapour cloud of about 200mm thick. Thats going to be 18l of vapour, which requires 272ml of fluid. A heater 'well' will be big enough to have the heater and the fluid in. I think i'll make that well big enough to house 500ml of fluid. I want to have a pretty good "head room" for the cloud so, i think we'll build the sides up so they are 600mm tall.
I'll put thermocouples in
(a) the heating well
(b) a little above the liquid level for the well
(c) 100mm above the well. This is where the board will sit, when it is lowered into the tank.
(d) 200mm above the well. This should represent where the vapour should 'reach'.
Cooling system to be designed yet
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Hello everyone,
It seems everyone has gone quiet on this front. I just wanted to let anyone interested know that I am indeed crazy enough to keep trying with this.
The UPS guy showed up today with a neat 7kg package (please don't ask how much this cost :'( ):
(https://dl.dropboxusercontent.com/u/387299/galden/IMG_2282.jpg)
(https://dl.dropboxusercontent.com/u/387299/galden/IMG_2284.jpg)
(https://dl.dropboxusercontent.com/u/387299/galden/IMG_2285.jpg)
Note the warning about 300C, this stuff decomposes into hydrofluoric acid so great caution is needed with the heating.
I am having a container fabricated as we speak out of ASTM302 stainless steel, and the ASTM440 6.35mm stainless steel ball bearings for the induction heater are on the way. Unfortunately I had to get it made at a metal shop, as I do not have a TIG welder nor the skills to TIG weld. And the price of a good TIG welder pales in comparison to the price of galden.
I went stainless because I don't want to have to deal with oxidation at all. It was a little more expensive, but I am considering this an investment in my own learning, and I hope in the open source community. I've gained a lot from open source, and if this turns out ok then I will document the project and make it available online as my way of giving back.
I also have some 3mil/3mil breakout boards coming with a 0.5mm pitch BGA on them (atmega48) for testing. But they were slowed up by Chinese new year, so I don't have them yet.
As a very strange sidenote, the inside of the package smells like mint (including the paper documentation). I have no idea why.
In the meantime, I've been brainstorming some ideas for computer vision software for machine-assisted placement of fine-pitch BGAs. But now that the galden has arrived, I'm planning on doing some characterisation experiments with it, particularly with respect to the evaporation rate. I can't guarantee I'll be able to do anything else as my real work is about to crank up, but if anyone has any good ideas for some tests please let me know. Keep in mind that I'm an EE, not a chemist ;)
My bank account hurts, but it's for science. ^-^
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Nice one Jeremy.
I also have a container on the way and need to purchase some of the chemistry.
I dropped anote to solway enquiring where in this part of the world I could get the fluid. So far silence.
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I have been searching "vapour phase soldering" in Google for more than an hour, but I still haven't found answer to one question:
At what step is the solder put onto the PCB?
I watched many Youtube videos (there wasn't any close up one). They put the PCB solderless PCB inside the hot cloud. And when they take it back, there are solders on the pads. Where did that solder come from? The boiling liquid doesn't contain any solder as far as I understood.
Can you please clarify this?
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I have been searching "vapour phase soldering" in Google for more than an hour, but I still haven't found answer to one question:
At what step is the solder put onto the PCB?
I watched many Youtube videos (there wasn't any close up one). They put the PCB solderless PCB inside the hot cloud. And when they take it back, there are solders on the pads. Where did that solder come from? The boiling liquid doesn't contain any solder as far as I understood.
Can you please clarify this?
They use solder paste, when it reaches the melting point the components stick with the surface tension of the solder.
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I have been searching "vapour phase soldering" in Google for more than an hour, but I still haven't found answer to one question:
At what step is the solder put onto the PCB?
I watched many Youtube videos (there wasn't any close up one). They put the PCB solderless PCB inside the hot cloud. And when they take it back, there are solders on the pads. Where did that solder come from? The boiling liquid doesn't contain any solder as far as I understood.
Can you please clarify this?
They use solder paste, when it reaches the melting point the components stick with the surface tension of the solder.
Thanks MK. I always though that "solder paste" is just another name for "flux". I made a quick research and learned about it.
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hkBattousai: the solder paste appears as a matte gray substance, but under high magnification it contains many small balls of solid solder in a flux gel. at the instant it reflows, it turns shiny and bright. Since it is sticky before reflow, it is used to stick components down to their pads before the board is moved to the reflow machine.
You can see the tiny solder balls melting together in this video:
Micro Laser Soldering System (https://www.youtube.com/watch?v=KnyB9btlhS8#)
Watch at 1:00 and 1:40
jeremy: the data sheet that comes with the HT230 in your picture shows a BP range of 222-237 C (10-90%). That seems to be quite close to a previous poster's figures for LS230:
Some more data, that i was able to obtain tells me that;
The Distillation spec range of the HT230.
10% > 210C, 90% < 250
Compared to the LS which is
10% < 222, 90% < 235
Is there an error somewhere?
Edited: I see that the first figures are for the specific batch you received. So it looks like your batch is within the same range as the worst-case spec for LS230, implying it may work perfectly fine in machines designed for LS230.
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Hi all,
I've just started using an Asscon Quicky 300 (stop sniggering) vapour phase reflow soldering machine at work, with HT-230 Galden and lead-free solder paste. It worked pretty well on my first try though my stencil might be a little thick (thickest option from OSHstencils) - I got some solder bridging on a 0.5mm pitch LQFP so I needed to rework that with some solder braid, but very happy for a first try as it saved me about two days worth of hand soldering on that board.
I have the manual for the machine (on paper only at present), and I have recorded some temperature profiles at a couple of places in the chamber. It is an interesting machine. The top glass door has a seal around it which is pressed tightly by a clamp to stop vapour getting out - I had a thermocouple wire going over the seal and a bit of Galden leaked out there due to the wire preventing a good seal in that location. The board carrier stays put down near the bottom of the tank a few centimetres above the fluid surface, during the heating and cooling periods (~ 2.4kW flat heater plate UNDER the base of the tank). The tank holds 1kg of Galden. The vapour rises in the chamber and when it gets to the board, the board heats very rapidly. You can see the solder melt, then once the board reached the top temperature (229C) I gave it another 20 seconds and pressed the button to stop the cycle (trying not to cook the chips for too long) at which point it dumps cooling water through a stainless steel pipe that is immersed in the fluid tank at the bottom of the chamber, and now-hot water from this pipe drains out through a pipe from the bottom of the machine. The water-cooled stainless pipe quickly starts re-condensing the vapour and the board cools down fairly rapidly. When the board gets back down to about 150C you can wind the board up to the top of the chamber to dry off and cool a bit more. If you don't press the button to stop the cycle when the solder has melted, then the vapour keeps rising in the chamber until it gets to a temperature sensor about half-way up the front wall of the chamber which terminates the cycle. That would result in the board down the bottom of the tank being at 230C for about 3 minutes which was longer than necessary so I used the stop button instead of waiting for the vapour to reach the sensor.
If anyone wants more info on this machine let me know. I would like something like this for home too, though then I'd probably need to buy some Galden of one of you.
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Chris, thanks for your input, despite what others might think of that unit it sounds like it did the job fine.
Was the paste in good condition or date expired?
How long did your process take from "go to whoa" ?
PS. Put a flag in your profile so jeremy can know where you are if he has Halon to sell
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Hello everyone,
Sorry I've been a bit quiet, it's been a super busy few weeks for me. I'm already planning to sell some to HT230 to @IconicPCB (can you do the @ thing here?), but I still need to give him a call (sorry!)
jeremy: the data sheet that comes with the HT230 in your picture shows a BP range of 222-237 C (10-90%). That seems to be quite close to a previous poster's figures for LS230:
...
Is there an error somewhere?
Edited: I see that the first figures are for the specific batch you received. So it looks like your batch is within the same range as the worst-case spec for LS230, implying it may work perfectly fine in machines designed for LS230.
Yep, the company I bought it from (TMC industries) sells it to people for use in reflow ovens.
Chris: Thanks very much for your input. Could you possibly get us some rough measurements of the inside of the cavity? Maybe even a picture or two :) It's interesting that it has a seal on top, I was planning on doing this too with some RTV silicone gasket and a sheet of borosilicate glass. How is the lifting of the board done? Is it using chains, or is it done with a leadscrew? And finally, what sort of guides are on the board carrier; are they just metal drawer slides or something like that?
Some updates on my end:
-> The metal shop is currently fabricating my stainless container. It's 1.2mm stainless, so I think warping might be a little bit of a problem. But for revision 1, I think it will be fine.
-> I purchased a 2kW induction cooktop, which won't detect my 1/4" stainless ball bearings as a saucepan and so turns itself off. I have 400 of them and they are definitely induction compatible, so I'm trying to decide between modifying the stove, or just getting a thin sheet of steel to activate it. I'll probably go for the sheet.
-> I've got some 0.5mm pitch BGAs (with PCBs) to solder. Should be a good challenge ::)
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Chris, thanks for your input, despite what others might think of that unit it sounds like it did the job fine.
Was the paste in good condition or date expired?
How long did your process take from "go to whoa" ?
I'll try to post a pdf file with the measured temperature profile on the board, from which I estimate that the whole process might have taken 25 minutes.
The paste has been in the original syringe in my fridge for a year and a half. It is Chipquick brand, SMD291SNL10 96.5/3/0.5. It still seems OK to me.
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Could you possibly get us some rough measurements of the inside of the cavity? Maybe even a picture or two :) It's interesting that it has a seal on top, I was planning on doing this too with some RTV silicone gasket and a sheet of borosilicate glass. How is the lifting of the board done? Is it using chains, or is it done with a leadscrew? And finally, what sort of guides are on the board carrier; are they just metal drawer slides or something like that?
I'll try to get you some more info next week if I have time. The board is on a perforated metal tray that has some stand-offs or feet, and those rest on the bottom of the chamber, above the central fluid reservoir with the cooling pipe in it. The mechanism to raise the board is just some stainless steel wire attached to and wrapped around a shaft with a knob on the end that lets you wind it up by hand. Nothing fancy, and no slides.
I'll attach the Quicky manual in case someone is able to buy one at auction etc. as the manual seems tricky to find. It is a nicely made unit and if I needed such a thing for my business then I think it would be a good purchase. For a hobby budget, probably something DIY would be in order, however it may be worth adding all of the same safety features to prevent creating toxic decomposition products that could otherwise result if it nearly boils dry.
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So as I now understand it this Quicky unit just adds distilled water to the Galden to cool it off?
So the students on that youtube experiment weren,t so stupid after all.
I am amazed I would have thought of some more elegant way of coolong like running water through tubes in the fluid as lets say a destillation column in chemistry works. So if the water is added in the cooling stage what hapoens to all the steam and how does the unit prevent the steam for teansporting the Galden vapour along with it?
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Cooling is by passing the cold water ( relative to the Galden) through the tank in a stainless steel tube, thus condensing the vapour, and the cold water is boiled and vented, the boiling water absorbing the heat in the hot Galden so that at the end of the cooling cycle it will be below its boiling point, and at around 80C or so. The water never contacts the Galden, it is only used in a heat exchanger to cool it.
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So as I now understand it this Quicky unit just adds distilled water to the Galden to cool it off?
So the students on that youtube experiment weren,t so stupid after all.
I am amazed I would have thought of some more elegant way of coolong like running water through tubes in the fluid as lets say a destillation column in chemistry works. So if the water is added in the cooling stage what hapoens to all the steam and how does the unit prevent the steam for teansporting the Galden vapour along with it?
As SeanB said, (and you suggested would be a good idea) the water is put inside a stainless steel pipe, and that pipe is in the Galden, but water does not touch the Galden. It doesn't even make loud boiling noises or let visible steam out through the drain pipe when it does the cooling part of the cycle so I wonder if they have some trick to make it gently add the water.
There is also a rectangular tube section that forms a sort of ledge around the walls of the tank about 2/3rd way up, and I think that might be water cooled as well, to reduce vapour reaching the top of the chamber. Perhaps that rectangular tube around the tank is the reservoir for the water, but I don't know yet.
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The ledge is a condensate drip tray, it simply adds a large surface at a point, and yes, there is a cooling water pipe behind it to circulate the cooling water when it is desired to cool the chamber. The vapour cools on it, forms a layer of liquid and then the ledge collects all of it and allows it to trickle down the wall in a corner back to the bulk liquid below.
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I tried it with a simple setup (30€ induction cooker, cooking pot with glass cover, Fluke 179 thermocouple) and it worked fine, without complicated cooling systems. The loss of Galden 230 was negligible.
(https://engineeringarts.files.wordpress.com/2015/04/galden.jpg)
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I tried it with a simple setup (30€ induction cooker, cooking pot with glass cover, Fluke 179 thermocouple) and it worked fine, without complicated cooling systems. The loss of Galden 230 was negligible.
Nice job. :-+
Care to share in more detail?
Temp?
Solder type?
Total time?
M3 capacity of your pot?
What height is your basket?
Galden used (ml)?, Galden lost?
Can you easily observe the reflow happening?
We all hope it is that simple. :-+
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I used Galden LS 230 so the temperature is 230°C, enought for the lead free solder paste ("CR 88" from EDSYN Sn96,5 Ag3,5)
The pot is for cooking asparagus, I don't know the volume. It's slim and high and has a metal basket. Only 100ml of Galden was used. I marked the level on the container and noticed no level drop after filling the cooled down Galden back after soldering, but my measuring methode was not exactly scientifically correct so a small loss is expected....
It was surprisingly simple and fast. And no tombstoning although there are a lot of 0402s on the board.
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Can you set the temp on the cooker or did you just heat till you saw the vapour?
Did you actively cool down the Galden with cold distilled water? Can you describe in more detail the followed steps?
What are your next improvements on the process?
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I turned the cooker on until the Galden boiled, lowered the PCB (on the basket) slowly (~1 minute) while watching the temperature with the thermocouple, waited until the solder changed phase and pulled the basket out. No active cooling, no fan.
No improvements needed.
Maybee I try cooling the upper end of the pot with a towel soaked in cold water.
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remind me not to eat asparagus at your house :)
then again, it might be perfectly safe, or is this cooker now used exclusively for electronics?
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Galden *should* be safe (it's inert) and the equipment is used for electronics only. I would however recommend a good ventilation....
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OK.. some time later ad a few dollars down the track....
Piccies of the machine vessel and frame coming together...
Various views showing cooling coils and support structure.
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one more
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no more
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Can anyone recommend any vendors who will sell small amounts of Galden/Fluorinert type fluids?
I'd like a small amount to try some experiments with, but I don't want to commit to a gallon of the stuff, since it's uber expensive.
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This is page 14 of the topic.
Member JEREMY ( mid page 12 ) had some Galden to sell. Get in touch with him he may be able to help.
EDIT:
It may be an idea to tell us where in the world is Carmen Sandiego so we can provide better advice
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Hello,
Did any one buy an Asscon Q300? How much did you pay? Are any used available?
I want to buy one but I am looking for a less expensive occasion.
I asked Asscon and they offered one for 7200€ to me which seems a little expensive to me.
Any ideas where to get one for less money?
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@ IconicPCB
looks really nice. Any further progress so far?
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Too early at the moment, need to implement cooling regime. Have purchased a smart relay controller and designed a thermocouple receiver interface card for the smart relay analogue inputs.
Expect to do some of these things during this week.
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Im just getting back into this project again as the crazy time of the year has passed.
I got an email from Hawker Richardson, and they are selling 5kg of Galden LS215 for $AUD 1225 on their web store. Thats a resonably cost effecitve price.
I want 2.5kg, anyone interested in splitting a bottle with me? ( I figure in my device, i'll probalby only need about 1kg )..
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Im just getting back into this project again as the crazy time of the year has passed.
I got an email from Hawker Richardson, and they are selling 5kg of Galden LS215 for $AUD 1225 on their web store. Thats a resonably cost effecitve price.
I want 2.5kg, anyone interested in splitting a bottle with me? ( I figure in my device, i'll probalby only need about 1kg )..
I'd prefer the 230 degree stuff - used it at work with lead free paste and turned out very well. Due to the finely divided particles that I seem to get everywhere, I'd prefer not to use leaded paste at home if the lead free works well.
Chris
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Im just getting back into this project again as the crazy time of the year has passed.
I got an email from Hawker Richardson, and they are selling 5kg of Galden LS215 for $AUD 1225 on their web store. Thats a resonably cost effecitve price.
I want 2.5kg, anyone interested in splitting a bottle with me? ( I figure in my device, i'll probalby only need about 1kg )..
I'd prefer the 230 degree stuff - used it at work with lead free paste and turned out very well. Due to the finely divided particles that I seem to get everywhere, I'd prefer not to use leaded paste at home if the lead free works well.
Chris
They are also selling the 230, as well, its a little more expensive, but still the cheapest option in A/NZ.
Interested to know what your experience of "divided particles is".
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They are also selling the 230, as well, its a little more expensive, but still the cheapest option in A/NZ.
Thanks. Unless someone is doing a group buy I'll leave it until I have the time to build the rest of the thing, and/or lose access to the machine at work.
Interested to know what your experience of "divided particles is".
By "finely divided" I just meant that the solder paste contains very small particles of solder, in comparison to most of the solder blobs that result from hand soldering. I suspect that smaller particles would be more difficult to clean up and more likely to get ingested unless significant precautions are taken. My only experience with (lead free) paste is that I made quite a mess of the bench, though the boards turned out very well.
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The finer the particles the more problematic the paste.
A major problem is the shelf life of paste. major contributor to lack of shelf life is ratio of ball surface area to volume of solder ball.
As the ball size reduces the ratio of surface area ( for area read solder dross.. oxidized solder) versus ball volume ( read healthy virgin alloy material)increases providing for a joint with possible dross inclusions.
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Hello, I read the thread (but couldn't watch the videos) and couldn't find an answer to this question : in a homemade setup, Galden in a cooking pot for example, at which point is the PCB inserted ? Is it placed above the liquid Galden before heating up so the PCB will slowly warm up with the air ? Or is it dipped after the Galden turned to vapor and if so, is the PCB warmed up on the side before to avoid a thermal shock ? Thank you, Koen.
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It doesn't much matter which order, since heating only happens in the zone of condensing vapor. As a practical matter, the PCB is lowered into position first, and then heat is supplied to move the vapor zone up over the PCB, because tighter control of vapor is achieved.
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Hello, I read the thread (but couldn't watch the videos) and couldn't find an answer to this question : in a homemade setup, Galden in a cooking pot for example, at which point is the PCB inserted ? Is it placed above the liquid Galden before heating up so the PCB will slowly warm up with the air ? Or is it dipped after the Galden turned to vapor and if so, is the PCB warmed up on the side before to avoid a thermal shock ? Thank you, Koen.
Pretty much as in this post:
https://www.eevblog.com/forum/projects/vapour-phase-soldering/msg596305/#msg596305 (https://www.eevblog.com/forum/projects/vapour-phase-soldering/msg596305/#msg596305)
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Some progress...
Tried domestic induction heating hot plate... did not work... not because the fluid did not get hot but because the source of heat ( ferromagnetic stainless steel base ) but because the power density was too high.
Had to rethink the heating requirement and limit the input power density. So this time with same power input but from a rearranged source have brought the oven temperature up to 230C.
Need to do some mechanical tweaking in the hope of improving heating rate.
I found that LS230 evaporates at lower temp than the notional 230C. Vapor of some lighter fractions seems to evolve at temperatures around 100C. Do not know what they are but.. it is what it is.
A note of WARNING.. GALDEN decomposes into TOXIC compounds if heated above the typical range of operation be careful to manage power input into the boiler zone.
Next step will be to connect cooling fluid pipes and re run the experiment with the view to containing vapor with minimal losses.
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Hi
All of the Galden fluids evaporate if you leave them in the open. The lower temperature stuff goes faster, but they all "vanish into air" if left out for a while. Best to put them in a tightly sealed bottle when not in use. Unfortunately the way we were using them that was not an option. Galden made a lot of money off of us on that project ..... We got somewhat lower loss rates off of the gear with chilled collars on them. In the end it was not clear if the compromises involved in that made sense or not.
Bob
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Bob do you mean to say that Galden evaporates also at roomtemperatures so you are forced to store it in a tight container after use?
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Bob do you mean to say that Galden evaporates also at roomtemperatures so you are forced to store it in a tight container after use?
Hi
Yes, that's exactly correct. They do have a finite vapor pressure (even at room) so they head off into the air. Some of the stuff we used was lower temperature than the 230 so it was what we had the biggest problem with. How tight the container needs to be or if a simple float cover would work ... no idea. We went to bottles. One wise guy suggested a dropping a chunk of lard on top of the hot fluid ...
Bob
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Of course when I read the word "Fluorinert", I thought of the Cray-2
A very interesting bit of electronics history...
See http://www.computerhistory.org/revolution/supercomputers/10/68 (http://www.computerhistory.org/revolution/supercomputers/10/68)
also
https://en.wikipedia.org/wiki/Cray-2 (https://en.wikipedia.org/wiki/Cray-2)
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Of course when I read the word "Fluorinert", I thought of the Cray-2
A very interesting bit of electronics history...
See http://www.computerhistory.org/revolution/supercomputers/10/68 (http://www.computerhistory.org/revolution/supercomputers/10/68)
also
https://en.wikipedia.org/wiki/Cray-2 (https://en.wikipedia.org/wiki/Cray-2)
Hi
The stuff is also a "specified fluid" for bubble leak testing to some of the mil specs. The exact mix of this or that varies a bit, but yes, it's all pretty much the same stuff.
Bob
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Hello, I bought the asparagus cooking pot introduced earlier in this thread a while ago (at Blokker in Belgium) and it does the job.
I was looking for something unrelated tonight and stumbled upon this which could be better suited and interesting to some of you : Airtight storage bucket for laminating tools (http://shop1.r-g.de/en/art/300500) (The container is filled up to the sieve with acetone (about 2 cm), brushes and other tools are placed on the sieve afterwards the container is sealed airtight), 20EUR, from Germany.
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Hello,
would anyone know of a low-volume supplier of Galden 240 ? Thank you.
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Member Jeremy i think was interested in selling a couple of liters.
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I just found these today:
https://www.epa.gov/sites/production/files/2016-02/documents/pfc_heat_tranfer_fluid_emission.pdf (https://www.epa.gov/sites/production/files/2016-02/documents/pfc_heat_tranfer_fluid_emission.pdf)
http://multimedia.3m.com/mws/media/122381O/reducing-emissions-of-pfc-heat-transfer-fluids.pdf (http://multimedia.3m.com/mws/media/122381O/reducing-emissions-of-pfc-heat-transfer-fluids.pdf)
https://www.gpo.gov/fdsys/pkg/FR-2013-04-05/pdf/2013-07977.pdf (https://www.gpo.gov/fdsys/pkg/FR-2013-04-05/pdf/2013-07977.pdf) (page 3)
http://www.ghgprotocol.org/files/ghgp/tools/Global-Warming-Potential-Values.pdf (http://www.ghgprotocol.org/files/ghgp/tools/Global-Warming-Potential-Values.pdf)
So the global warming potential of Galden seems to be maybe 10000 times higher than CO2 but the estimates vary a lot. If I did buy any Galden then I might feel fairly guilty about letting a lot of the Galden escape or disposing of it in a manner other than passing it on to someone who wants to use it. According to the first carbon footprint calculator I could find with google, a return flight from Sydney to London is equivalent to allowing about 500mL of Galden to evaporate, very very roughly. This would also be about 2 years worth of my car driving.
Given that most people reading this would not be reflowing boards all day every day, and so most of the time the Galden would be just sitting around, and that Solvay's FAQ suggests that it is good at escaping, either a very well sealed lid on the reflow machine or some way of draining down the chamber into a well sealed bottle would seem to be a good feature. (I also think some way of re-distilling the Galden to clean it would be nice.)
[Text below has been edited as I looked again and found that I had failed to notice some things. The addded text is in bold:]
On a related note, at work I found that some bottles of Galden from a few years ago when they were trying various different temperature grades. These were not the original type of bottles from Galden, but smaller ones from somewhere else. All of the LS200 and LS215 bottles seemed to have emptied themselves Some of the bottles were empty, though I can't be sure how full they were to start with as nobody recorded that. But I can't believe they would have bothered to carefully label a bunch of empty bottles and then store them, though the fluid might also have been used to top up the reflow machine without getting rid of the bottles when finished. (And no, I didn't take it!) The non-original bottles that they used don't seal all that well, and I think it evaporated. However, a bottle with the lid screwed on tightly labelled LS215 dated 2004 had a fair bit in it so it doesn't escape as fast as I thought. The LS230 bottle still has some left in it. It would be interesting to weigh that not-yet-empty bottle and see whether it gets lighter, whilst I look for a better-sealing bottle. You can see from the datasheet that the higher temperature grades have less vapour pressure at room temperature, and so it makes sense that they evaporate less quickly.
http://www.solvay.com/en/binaries/Galden-PFPE-Heat-Transfer-Fluids_EN-220543.pdf (http://www.solvay.com/en/binaries/Galden-PFPE-Heat-Transfer-Fluids_EN-220543.pdf)
Perhaps it would make sense to keep the bottles in a fridge, or keep the whole reflow machine in a chest freezer when not in use. (I am assuming a separate lab fridge or freezer, not the kitchen one!)
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Remember that you are talking about a liquid with a boiling point of 200°C! Unless you operate your line in Death Valley in the summer, precious little escaping vapor will make it into the atmosphere.
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Remember that you are talking about a liquid with a boiling point of 200°C! Unless you operate your line in Death Valley in the summer, precious little escaping vapor will make it into the atmosphere.
Water has a boiling point of 100oC however my non heating just rotating discs with a fan working Venta passive humidifier can evaporate upto 10 liters of water in my livingroom of 20oC each and every day in the winter.
So evaporation of liquids can well take place at lower temperatures than the boiling point of said liquid.
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Remember that you are talking about a liquid with a boiling point of 200°C! Unless you operate your line in Death Valley in the summer, precious little escaping vapor will make it into the atmosphere.
The vapour pressure of galden is around zero in most rooms, so you might be surprised how quickly it evaporates in those rooms, even given its high boiling point.
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A quick Google for "Galden storage" shows it must be kept in a sealed container.
http://www.appliedthermalfluids.com/home/shop/galden-d02ts-pfpe/ (http://www.appliedthermalfluids.com/home/shop/galden-d02ts-pfpe/)
Galden D02TS Testing Electronic Fluids Shelf Life
Galden Fluids have a guaranteed shelf life of a minimum of 5 years from date of shipment if stored in the original sealed container at ambient temperatures.
Others suggest:
Keep away from heat and sources of ignition
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I have LS230 sitting in the oven covered with just a lid (not airtight), reflowing small batches of boards once in a while. During about 6 months didn't notice any serious amount leaking away. I actually cleaned the oven, so removed the fluid back in the bottle. Didn't seem that more than 5% was lost
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Remember that you are talking about a liquid with a boiling point of 200°C! Unless you operate your line in Death Valley in the summer, precious little escaping vapor will make it into the atmosphere.
The vapour pressure of galden is around zero in most rooms, so you might be surprised how quickly it evaporates in those rooms, even given its high boiling point.
Pratical experience is showing that this largely is not the case. I've not lost any noticabel fluid out of my tank.. ( its got a stainless steel lid on it but not particaully well sealed )
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I edited my post above as I noticed that I was wrong about all of the LS215 bottles being empty. I still think that if one is concerned about global warming as well as cost then it is worthwhile using bottles that are gas-tight (so they hold some slight pressure without leaking), and that it would be worth following Solvay's recommendation on seal materials. Also to minimise evaporation of Galden at room temperature, it might be better to choose the higher temperature LS230 grade rather than LS215, regardless of solder type. My impression is still that it is worthwhile to make sure the chamber lid seals well, like on the Asscon Quicky, because I found that there are drops of Galden condensation all over the inside of the glass lid, even though the machine hasn't been used in the last a few months. I found that the boards are not totally dry when removed from the chamber, and so I think that after soldering, it might be nice to keep the board warm (maybe 100 degrees C ?, e.g. with IR lamps shining through the glass lid) after the board has been raised but whilst it is still in the cold chamber (preferably with the chamber chilled), to recover the last traces of Galden before the board is removed.
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IconicPCB, did that project go anywhere? I've been interested in building a vapor phase machine but I don't know how much work you've already done. I imagine the most headache would be the vapor cooling since that has to deal with either superheated steam or steam venting.
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Tombstones are just painful. We get the odd ones happening in our reflow oven from time to time.
I know this is an old thread, but just out of curiosity: did you try the notched paste mask (see picture)?
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Tombstones are just painful. We get the odd ones happening in our reflow oven from time to time.
I know this is an old thread, but just out of curiosity: did you try the notched paste mask (see picture)?
IMDES is full of BS. Lower amount of paste can somewhat help but the main issue is that supposed temperature profile (with proper rise curve) on their website is totally fake. Just making my own crude controller in one evening, without any fine tuning reduced tombstoning by at least a factor of 10.
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I do use a notched stencil, like that, but the reason you use it, is NOT for tombstones!!! Its there to help mid component balling.. ( tiny bits of solder that find their way off the pad and 'ball' up and sit mid way on the component.
Like Wraper, the profile that a stock IMDES machie produces is just garbage.
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Thanks for the feedback. :-+
I'll propably have to roll my own controller then?
The following pieces comes to mind with the UI on the phone:
- ESP32: https://www.aliexpress.com/item/ESP32-WROOM-32-ESP32-WROOM-32D-ESP-WROOM-02-ESP-WROOM-02D-Module-Espressif-Original/32963147246.html?spm=a2g0s.9042311.0.0.27424c4do9R97H (https://www.aliexpress.com/item/ESP32-WROOM-32-ESP32-WROOM-32D-ESP-WROOM-02-ESP-WROOM-02D-Module-Espressif-Original/32963147246.html?spm=a2g0s.9042311.0.0.27424c4do9R97H)
- PSU: https://www.aliexpress.com/item/AC-DC-110V-220V-to-3-3V-700mA-2-3W-Switching-Switch-Power-Supply-Buck-Converter/32833671094.html?spm=a2g0s.9042311.0.0.27424c4dqlJOSB (https://www.aliexpress.com/item/AC-DC-110V-220V-to-3-3V-700mA-2-3W-Switching-Switch-Power-Supply-Buck-Converter/32833671094.html?spm=a2g0s.9042311.0.0.27424c4dqlJOSB)
- Temp: https://www.aliexpress.com/item/MAX6675-K-Type-Thermocouple-Temperature-Sensor-Converter-Board-For-Arduino-SPI-Interface-Module-For-Arduino-50mA/32834862835.html?spm=a2g0s.9042311.0.0.36474c4d2fRX9M (https://www.aliexpress.com/item/MAX6675-K-Type-Thermocouple-Temperature-Sensor-Converter-Board-For-Arduino-SPI-Interface-Module-For-Arduino-50mA/32834862835.html?spm=a2g0s.9042311.0.0.36474c4d2fRX9M)
- Heat: https://www.aliexpress.com/item/SSR-25DA-DC-control-AC-SSR-white-shell-Single-phase-Solid-state-relay/32295725401.html?spm=a2g0s.9042311.0.0.27424c4dYBRlNf (https://www.aliexpress.com/item/SSR-25DA-DC-control-AC-SSR-white-shell-Single-phase-Solid-state-relay/32295725401.html?spm=a2g0s.9042311.0.0.27424c4dYBRlNf)
Do you have a better solution?
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I have just reflowed my first batch of boards with vapour phase. I am very happy with the quality of soldering achieved. Currently i am using a cheap hotplate, and an asparagus steamer with approximately 200ml of Galden 230 in the bottom, and the pcb in a mesh tray above the fluid. I have a dual channel temperature meter, and am measuring temp in the fluid and temp 1" above it. I currently heat on full power until the galden hits 220 deg C, then i turn off the heat and let it coast until the board has seen 230 deg C for 40s. After that i quench the entire pot in a sink of cold water.
After doing this on 3 runs the galden remaining is appearing milky coloured, is this to be expected?
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The 'milky' appearnace will be flux that is now floating ( not disolved ) in the galden.
I'd seriously suggest that your profile woudl be pretty scary if you are just heating it full on.
Get a little bit of PID control.
( see my thread about my frying pan project ).
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Yes. Filter it with coffee paper filters from time to time.
Don't waste your time and money complicating a process that works so easily.
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Yes. Filter it with coffee paper filters from time to time.
This works really well
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https://www.youtube.com/watch?v=czwRntpEzgg (https://www.youtube.com/watch?v=czwRntpEzgg)
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The thermocouple should be attached to the board, not put in the boiling liquid; it's physically impossible for it to be anything other than 230°C, no information is gained.
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Thanks for the help, will run the lot through some filter paper and see if that helps. I just ran another batch, and getting some tombstoning, so probably will upgrade to a PID controller at some point soon.
RE the thermocouples, the one above the board is there so that i can be sure that the whole board has reached thermal equilibrium before this sensor hits 230. Regarding the other one, I start from cold with the board in place, so having a sensor that lets me know how long until the vapour cloud forms is useful as i am operating this manually.
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Coffee filter will only help if you rapidly filter the fluid after reflow. Otherwise flux will just deposit on walls and galden will become clear again.