Author Topic: DIY Vapour Phase Frying Pan Project (Read 10101 times)

mrpackethead · « **on:** June 03, 2019, 04:33:39 am »

This is to document a practical and modestly costing DIY Vapor Phase Soldering Project using a Domestic Electric Frying pan. There has been a lengthy discussion ( https://www.eevblog.com/forum/manufacture/practical-diy-or-modest-cost-vapor-phase-does-it-exist-yet/ ).

After quite a lot of experimenting, i've been able to get very good Vapour Phase Re flow using a domestic frying pan. My experiments have used a wide collection of bits and pieces to 'hack it together' but now i want to tidy it all up so its easy to use and replicate ( i now want to make quite a few of these ).

Vapour Phase Reflow works by heating fluid ( Galden HS230 ), to boiling and creating a cloud of 'hot vapour'. The hot vapor condenses on the PCB and parts and causes it to heat up and solder. There are some advantages of using this technique. Its hard to overheat the boards/parts as the maximum temp they reach is 230C, which is the temp of the vapour. Vapour Phase in fact is not a new tech, it was the first reflow tech used when surface mount was invented. However it used some nasty fluids that were very Unfreindly. Now there are some much better fluids, which are much more inert and safe. Commerical VP is an expensive thing to buy. There have been a couple of attempts at low cost VP but the one which i bought was of very poor quality and implementation.

Its not a particulary complex project, you need to control the heating of an element and then control turning on a fan to cool it.
For this project, i've decided not to create an entire microcontroller system, but just enough electronics so you can connect your favourite single board computer, or in fact PC via USB to it. My experiments have been controlled with code written in python.

The parts;

(a) A frying pan - I've settled on using a Breville BEF560BSS. (https://www.breville.com/nz/en/products/woks-skillets-deep-fryers/bef560.html). Its highly probable that other pans will work, however there was a few things about this one that make it quite attractive. The list price on this pan is $A269, but i got mine for $80, ( dented box ) but i've regulally seen them for around $120

Its has a nice even power distribution in the pan. Theres not really any signifncant hot spots.
Its lid is nicely domed, and any vapor that hits it, seems to roll down the lid. The lid has a nice lip on it, as well, that seals it quite well
Its got plenty of power, 2400W
Its easy to remove the cover from the bottom, ( more on that later, but it really helps cooling )

(b) a big decent AC Fan. ( GoldAir GCDF140B ). You want something that can really drive a lot of air, getting enough air over the base of the pan when you want to cool it down, is really important. About $40-50

(c) Some Galden HS230 Fluid ( expensive, but you don't need much, and if you are careful, you dont' consume much

(d) A couple of Solid State relays, and heatsinks. I'm using Fotek SSR-25DA-H. You need to be careful to get genuine ones. Fotek is a good brand but there are 100's of fake copies on aliexpress/ebay. These will set you back about $12 for the SSR's and $3 for a power supply.

(e) In my setup, i'm going to wire in a couple of circuit breakers, and an RCD all on a Dinrail just to make it a bit safer as i intend to use this in a commerical setting where I need to have some compliance and OSH.

(f) A controller system, to glue it all together and control it. I've decided that instead of trying to code it into a dedicated microcontroller ( you coudl fesibly do that ), that it will get plugged into 'somethign' that has a usb port. My codes in Python.

I've sketched up the schematic for the controller board, which is attached. A MCP2221A provides an I2C / USB Bridge. There are a really good set of librarys for python to use with this. ( https://pypi.org/project/PyMCP2221A/ ) and it seems to work well with Windows and linux ( so good for a raspberry PI etc ).

MCP9600's are for connecting a K type Thermocouple to. At present i'm only using 1, but i'm provisioning space for up to four, as it might be useful to add extra measuring points later. If we dont' need them, it will just be blank spots on the PCB. I've also put a MCP23017 GPIO expander on it, which will be used to control those SSR's as well as provide some additional ports if you want to hook up extra things.. I'm thnking i'll put a stop/start button and maybe some indicator leds on. Its easy to put in now, and since its programmed in python really easy to add/modify to your hearts content.

Next job is to design a pcb.. I'm going to make it so it so it will have a coupel of DIN rail mounts on it, as i intend to mount all my peices on a Din Rail inside a nice tidy box.

I've reserved the next two posts, so i can add a BOM, and schematic's and stuff.

This project is entirely open. We will see where it goes, at the moment, i'm building it for my own use and if anyone else gets any interest out of it, then awesome..

I remember a time when we thought, meh, you can't use a home toaster oven to solder.. thats insane.

The project has taken some interesting twists and turns, but its now got simple again, I played with water cooling, and different size pans and systems. What i know now is that we can acehive a nice reflow profile, that can be cooled sufficently and that there is not a noticeable galden loss.

mrpackethead · « **Reply #1 on:** June 03, 2019, 05:27:22 am »

Links to various parts:

usb/I2C bridge
https://www.microchip.com/wwwproducts/en/MCP2221a

thermocouple Interface IC
http://ww1.microchip.com/downloads/en/DeviceDoc/MCP9600-Family-Data-Sheet-20005426E.pdf

SSR
http://www.fotek.com.tw/pdf/2013515_37275332.PDF
https://www.aliexpress.com/item/100-Authentic-original-SSR-25DA-SSR-25DA-H-FOTEK-Single-phase-solid-state-relay-25A/32834260762.html?spm=a2g0s.9042311.0.0.3aef4c4d1mMeEX

SSR Heatsink
https://www.aliexpress.com/item/1pc-Single-Phase-Solid-State-Relay-SSR-Aluminum-Heat-Sink-Dissipation-Radiator-Newest-Suitable-for-10A/32843767354.html?spm=a2g0s.9042311.0.0.3aef4c4d1mMeEX

K Type Thermocouples
https://www.aliexpress.com/item/K-type-Thermocouple-Stainless-Steel-probe-Thermocouple-100mm-200mm-2m-Cable-Wire-Length-Thermocouple-0-400C/32956256758.html?spm=a2g0s.9042311.0.0.27424c4dwPZW2x

Possible Frying Pans

Sunbeam FP8950 ( https://www.sunbeam.co.nz/Ellise-Stainless-Steel-Banquet-1.aspx ) Not tested, but looks promising.
Breville breville-bef560bss . This is what i've been working with, and does a good job.

It seems like it is not a good idea to use a Frying pan that has a non-stick coating, as this might be incompatible with Galden.

Options for 110V ( USA ). It seems that in NA, that Frying pans typicaly only go up to 1800W or so. That should be enough power, i've found that i'm tyically using less than half the power of the 2400W. It might require a little parameter changing but fundementally it should not pose a problem. If anyone finds a suitable pan that you can buy in the USA, let me know!

mrpackethead · « **Reply #2 on:** June 03, 2019, 09:57:34 am »

PCB designed. Its 43 x 88mm and is designed to be screwed onto some din rail mounts.

Altium Files attached.

Kean · « **Reply #3 on:** June 03, 2019, 05:37:18 pm »

Thanks for documenting this project - I'm going to give it a go

jeremy · « **Reply #4 on:** June 04, 2019, 11:02:10 am »

I just bought one from amazon AU

mrpackethead · « **Reply #5 on:** June 04, 2019, 11:13:57 am »

What part of Oz jeremy?

jeremy · « **Reply #6 on:** June 04, 2019, 11:21:08 am »

Brisbane. I’ve been tinkering with vapour phase for ages (I was one of the posters in the original thread) but I never came up with something I was happy with. My latest project was to basically build one of these electric frypans from scratch because I was worried how it would stand up to ~250C. But it seems you’ve found a winner.

mrpackethead · « **Reply #7 on:** June 04, 2019, 11:48:24 am »

I'm going to get the pcb design fabed up shortly and pending it all being good i'll make up a few more boards.

Suggest that you order the bits from Aliexpress as they will take the longest to get.

mrpackethead · « **Reply #8 on:** June 04, 2019, 11:49:28 am »

Wonder if Dave @EEVblog would be up for making a video of this once we have something to play with.

Kean · « **Reply #9 on:** June 04, 2019, 03:18:08 pm »

Quote from: jeremy on June 04, 2019, 11:02:10 am

I just bought one from amazon AU

Me too - I think I got the last one at the discounted price

intabits · « **Reply #10 on:** June 05, 2019, 10:36:14 am »

For the "poor man's version", inclined (by necessity) to mess about with some mechanicals, maybe the hotplates from one of these could be used with any metal dish of suitable characteristics? I imagine there would be a lot more choice in dishes when the electric heater requirement is eliminated. (Maybe with a heat spreader plate/heatsink between hotplate and dish)

(sorry, quick nighttime photo)

I've found a few of these by the side of the road for free.
Or similar hotplates might be had from and old electric stove...

mrpackethead · « **Reply #11 on:** June 05, 2019, 07:41:52 pm »

Anything is possible I guess. Explore possibilities and see what happens. A glass lid is handy. You might find a suitable frying pan for lot a lot. The hardest thing is the cooling. You might be able to repurpose a desk fan

trevwhite · « **Reply #12 on:** June 24, 2019, 09:11:57 am »

Hi, great information. Really appreciate the work you have put in to this and making it open source. I have some Galden HS230 and have been looking for a starting point to get a system up and running.

Is there any python code available yet for experimenting with?
Thanks
Trev

mrpackethead · « **Reply #13 on:** June 28, 2019, 08:29:24 pm »

SHi, Sorry that i went quiet on everyone. I've had been sucked into a project that did'tn let me breath, but escaped on Friday. :-) Many of you will know what that is like. But they paid well.

So, an update. I have pcbs, and all the parts to do a build. I'm actually going to use the Frying pan to build the frying pan controller boards. I've got a hacky hack hack controller set up and while its ugly, it does actually work. The SSR's and other bits have arrived from Aliexpress, they all came on free or nearly free shipping so it does take some time.

I'm going to set up my system on a DIN rail, and house it all in a polycarb box. Theres mains ( 240VAC ) in this project, you need to show the appropriate amount of care. I know we all sometimes go.. Sigh Another Warning but it has to be said. If your not confident with working with the mains, find someone who is to help you through it. I will be setting up my controller with both an RCD and and internal circuit breaker.

Software wise, the project will use Python to control / measure everything. I'm going to use the PyMCP2221A driver. So far i've been able to communicate with the Driver and set the GPIO bits. I did attempt to do some I2C stuff, but it did'tn work at the first attempt and I had run out of time.

Python from a pc is just one of many options.. The I2C bus is exposed on a header, so if you wanted you could connect a microprocessor, or you could use a raspberry PI.. Eventually i think i'll probalby use a Rpi, and stick it in the box, and then network connect it.

wraper · « **Reply #14 on:** June 28, 2019, 08:39:31 pm »

Quote

The SSR's and other bits have arrived from Aliexpress

That's not a good idea at all. Almost guaranteed to be counterfeit with triac rated <50% of current written on SSR and dodgy insulation.

mrpackethead · « **Reply #15 on:** June 29, 2019, 01:41:12 am »

Quote from: wraper on June 28, 2019, 08:39:31 pm

Quote
The SSR's and other bits have arrived from Aliexpress
That's not a good idea at all. Almost guaranteed to be counterfeit with triac rated <50% of current written on SSR and dodgy insulation.

This particually supplier is selling the genuine item. I have purchased from them before and have taken them apart and checked. ( once you open them its very apparent ). If you see the notes above i have already mentioned this issue. There are many clones out there. Not just on ali, but also ebay. First clue if they are about $2-3, they absolutely are fake.

trevwhite · « **Reply #16 on:** June 29, 2019, 07:22:06 pm »

Great to hear things are picking up again. Is there any special control loop/pid code implementation going to be required? I think that is the only bit that might be a little bit tricky.

mrpackethead · « **Reply #17 on:** June 29, 2019, 07:51:12 pm »

https://pypi.org/project/simple-pid/

trevwhite · « **Reply #18 on:** June 29, 2019, 08:19:11 pm »

The simplePID is pretty cool. Seems ideal to be able to develop with a PC and then transfer to anything that runs python. Really flexible approach.

A few months back I bought a largish stainless steel pan with glass lid. I think its about 23cm diameter and not far off tall. I do not have a heater for it yet. The Breville unit you are using does not seem to be available in the uk or at least not without a high shipping cost.

Anyone recommend a hotplate that would be beefy enough for this system. Sounds like I might need a few kw to get something working if I am to be similar to what is being used for this project. I quite like the pan so would like to find a hotplate. I think it being relatively tall should help with cooling.

mrpackethead · « **Reply #19 on:** June 29, 2019, 08:32:28 pm »

Quote

A few months back I bought a largish stainless steel pan with glass lid. I think its about 23cm diameter and not far off tall. I do not have a heater for it yet. The Breville unit you are using does not seem to be available in the uk or at least not without a high shipping cost.

^^^ this topic will be something that everyones going to have to work through depending on where they are located. For those in AU/NZ the breville is easy to get, and there is a similar zip. You just have to go and look to see whats about. Theres not an exact requirement to use the the same model. The 'harder' part is that you need to find something that does not have a non-stick coating. ( or be prepared to remove it ), as it appears that might be an issue. ( i have not tested that, mine is non-stick ).

Quote

Anyone recommend a hotplate that would be beefy enough for this system. Sounds like I might need a few kw to get something working if I am to be similar to what is being used for this project. I quite like the pan so would like to find a hotplate. I think it being relatively tall should help with cooling.

I doubt you'll need several kw. It probaby will work on signficantly less.

trevwhite · « **Reply #20 on:** June 29, 2019, 08:43:19 pm »

Well I wonder if one of these might be a nice place to start. All the control stuff is in there. I would just replace the brains

https://www.ebay.co.uk/itm/946C-800W-LED-Digital-Electric-Heating-Plate-Preheating-Preheat-Station-Solder/202638852463?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20140122125356%26meid%3Dd88ae75ba67149979ed8a698018f8f59%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D221348627102%26itm%3D202638852463&_trksid=p2047675.c100005.m1851
its 800W and not too much money.

mikeselectricstuff · « **Reply #21 on:** June 29, 2019, 08:53:07 pm »

Quote from: trevwhite on June 29, 2019, 08:43:19 pm

Well I wonder if one of these might be a nice place to start. All the control stuff is in there. I would just replace the brains

https://www.ebay.co.uk/itm/946C-800W-LED-Digital-Electric-Heating-Plate-Preheating-Preheat-Station-Solder/202638852463?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20140122125356%26meid%3Dd88ae75ba67149979ed8a698018f8f59%26pid%3D100005%26rk%3D3%26rkt%3D6%26sd%3D221348627102%26itm%3D202638852463&_trksid=p2047675.c100005.m1851
its 800W and not too much money.

I have one of those - they are awesome for reworking aluminium PCBs.

trevwhite · « **Reply #22 on:** June 29, 2019, 09:06:37 pm »

Reworking aluminium PCBs sounds like a nightmare!

Quote from: mikeselectricstuff on Today at 07:53:07 pm

I have one of those - they are awesome for reworking aluminium PCBs.

mrpackethead · « **Reply #23 on:** June 29, 2019, 09:16:54 pm »

Quite possible that it will work. For me being able to do a full panel ( roughly A4 page size ) is something that is important for me. And the breville does the job. Its just worked out to be a *really* easy build as i dont' need to find other bits and pieces to fit.

I'm not sure why but i am struggling to find similar models online for sale in the UK and US

mrpackethead · « **Reply #24 on:** June 29, 2019, 09:18:18 pm »

I use Vapour Phase for doing High Power LEDS on solid copper substrate pcbs. Its ideal. But reworking them.. Thats a nightmare.

mrpackethead · « **Reply #25 on:** June 29, 2019, 09:27:34 pm »

I've never tryed this, but it is an interesting idea. Vapour phase removal of a BGA. The lifting arm has a special high temp adhesive tape, that you use to stick it to the bga. Into the oven, and when its hot enough the spring will lift it up.

Of course everthing else gets molten.. but.. non the less its one way to doing it.

mikeselectricstuff · « **Reply #26 on:** June 30, 2019, 11:24:41 am »

Quote from: trevwhite on June 29, 2019, 09:06:37 pm

Reworking aluminium PCBs sounds like a nightmare!

Quote from: mikeselectricstuff on Today at 07:53:07 pm
I have one of those - they are awesome for reworking aluminium PCBs.

With a hotplate it's a piece of cake - place the PCB on the plate, then push it down with a probe where you want to rework, to improve thermal contact - then just pick off the old part, and drop on a (pre-fluxed) replacement.
If I was doing it a lot I'd make a rig with a hand-rest, but for thinks like replacing LEDs or popping mis-placed ones into place it's really quick & easy

Kean · « **Reply #27 on:** June 30, 2019, 12:20:16 pm »

Quote from: mikeselectricstuff on June 30, 2019, 11:24:41 am

With a hotplate it's a piece of cake - place the PCB on the plate, then push it down with a probe where you want to rework, to improve thermal contact - then just pick off the old part, and drop on a (pre-fluxed) replacement.
If I was doing it a lot I'd make a rig with a hand-rest, but for thinks like replacing LEDs or popping mis-placed ones into place it's really quick & easy

I bought a 946D with the same thing in mind, so glad to hear it works for you.
I think the 946D is basically the same as the C model, but also comes with clamps for doing phone screen repairs.

I also have a KADA 853A IR unit which I use for pre-heating for through hole rework & part salvage.

trevwhite · « **Reply #28 on:** June 30, 2019, 08:10:45 pm »

Quote from: mikeselectricstuff on June 30, 2019, 11:24:41 am

Quote from: trevwhite on Yesterday at 08:06:37 pm
Reworking aluminium PCBs sounds like a nightmare!

>Quote from: mikeselectricstuff on Today at 07:53:07 pm
I have one of those - they are awesome for reworking aluminium PCBs.
#smlt#/blockquote>
With a hotplate it's a piece of cake - place the PCB on the plate, then push it down with a probe where you want to rework, to improve thermal contact - then just pick off the old part, and drop on a (pre-fluxed) replacement.
If I was doing it a lot I'd make a rig with a hand-rest, but for thinks like replacing LEDs or popping mis-placed ones into place it's really quick #smamp# easy

I take it you have to watch the clock when doing this. You cant have the components hot for too long else damage will be caused?

How long does it take to heat up the board? Can it actually be used for reflow or is it too slow?

Trev

mrpackethead · « **Reply #29 on:** July 01, 2019, 10:00:35 am »

I spent a bit of time today, working out how i will describe the Reflow curve. I've decided i'll represent it in JSON. This makes it very easy to tweak and change, and add additional curve points if required, without adjusting the main code.

Everything shoudl be pretty straight forward to undersand. Looprate is in Hz.. This means we'll read the temp, and adjust the the PID settings 10times a second. We'll interpolate the values between the stated points.

{
  "name": "SAC305_LS230",
  "description": "Reflow profile for Frying Pan"
  "looprate": 10,
  "heating_max_duty_cycle": 100,
  "cooling_min_ontime": 1
  "profile":
     {
     "p1": {
             "time": 120,
             "temp": 150
           }
     "p2": {
             "time": 180,
             "temp": 160
           }
     "p3": {
             "time": 220,
             "temp": 230
           }
     "p4": {
             "time": 260,
             "temp": 230
           }
     "p5": {
             "time": 240,
             "temp": 200,
           }
     "p5": {
             "time": 300,
             "temp": 80
           }
     "p6": {
             "time": 360,
             "temp": 40
           }      
   }
}

mikeselectricstuff · « **Reply #30 on:** July 01, 2019, 10:31:01 am »

Quote from: trevwhite on June 30, 2019, 08:10:45 pm

Quote from: mikeselectricstuff on June 30, 2019, 11:24:41 am
Quote from: trevwhite on Yesterday at 08:06:37 pm
Reworking aluminium PCBs sounds like a nightmare!

>Quote from: mikeselectricstuff on Today at 07:53:07 pm
I have one of those - they are awesome for reworking aluminium PCBs.
#smlt#/blockquote>
With a hotplate it's a piece of cake - place the PCB on the plate, then push it down with a probe where you want to rework, to improve thermal contact - then just pick off the old part, and drop on a (pre-fluxed) replacement.
If I was doing it a lot I'd make a rig with a hand-rest, but for thinks like replacing LEDs or popping mis-placed ones into place it's really quick #smamp# easy
I take it you have to watch the clock when doing this. You cant have the components hot for too long else damage will be caused?

How long does it take to heat up the board? Can it actually be used for reflow or is it too slow?

Trev

For reworking Ali boards, it heats up quick enough that time isn't a big issue.
Probably a little slow for reflow (800W heater) but would probably work if you pre-heated it before putting the board on. if you wanted to do it a lot, I'd maybe look at adding an insulating lid to reduce heat loss

mrpackethead · « **Reply #31 on:** July 02, 2019, 09:08:03 am »

I have attached some intial code, that demonstrates how we can read the reflow profile from the json file, interpolate it, and create the set point.

Adding pid and temp read to this wont' take much longer, and i will change the timing so it does not use delay. rather actual system times, as reading the temp, and seeting the new PID will take time.

The code is python3;

Useage

python vpfry.py profile

mrpackethead · « **Reply #32 on:** July 04, 2019, 12:57:27 am »

THis is the box i'm going to use to mount everything in. Since its got AC power this is something that you dont just tag together on the bench to test.. I will get a combo 20A Circuit breaker/RCD for it as well.

I need to put an AC fan in the box i think.

All the bits ( including the control PCB ) will be able to be mounted on teh DIN rail. The heatsinks for the SSRS' have a profile that lets you slide them onto the din rail, they are a bit of a loose fit though, so i'll have to do somethign to secure them down.

Going to connectorise everything so its easy to swap things around. Adds to teh cost, but as this is a prototype it makes it a LOT more flexible.

mrpackethead · « **Reply #33 on:** July 05, 2019, 08:29:58 am »

Mm. so if you dont' have an reflow system, then how to do you reflow the board that you need for the controller?

Ran out of time to do this one today. Maybe tommorrow.

mrpackethead · « **Reply #34 on:** July 11, 2019, 06:04:56 am »

Assembled three pcbs, and yes, these where reflowed with vapour.

Couple of wee issues, but nothing thats a big deal.. I had the wrong USB connectors, so had to panelbeat a coupel of connectors to fit. :-) The USB bit stands up, and i can talk to the chip. will have to read the datasheets now to reach teh other devices.

mrpackethead · « **Reply #35 on:** July 15, 2019, 02:55:56 am »

This project has to be diyable. so ive been deliberate about picking things that are relatively easy to get.

For the cooling fan, I've picked a low cost ( i got this for NZ$19 on special ) AC desk fan. (23cm). I dont' need or want most of it, just the motor and the fan blade. It took a few minutes to disassemble, and got the motor out. Differnet models are going to need a differnet approach to this. I removed as much as i could of the osciallation unit, but have a good look at it, and dont' remove too much. In the case of this fan, i'm going to leave the plastic part attached, as while it did contain the gears for the oscillation, it also holds the rotor in place.

This is only a 30W fan. It looks like it will provide enough useful air flow.

trevwhite · « **Reply #36 on:** August 28, 2019, 12:31:22 pm »

Can I ask what method you used to vapour reflow these prototype boards?

Trerv

mrpackethead · « **Reply #37 on:** August 28, 2019, 07:33:00 pm »

Quote from: trevwhite on August 28, 2019, 12:31:22 pm

Can I ask what method you used to vapour reflow these prototype boards

I reflowed them in the frying pan, with galden.. and some 'human' logic.. and a thermocouple plugged into a multimeter.

trevwhite · « **Reply #38 on:** August 28, 2019, 11:51:42 pm »

Would it be possible to give a bit more detail? I would like to do a few boards and your experiences would really help my initial trials

tautech · « **Reply #39 on:** August 28, 2019, 11:59:13 pm »

Quote from: trevwhite on August 28, 2019, 11:51:42 pm

Would it be possible to give a bit more detail? I would like to do a few boards and your experiences would really help my initial trials

Read the first post and study the linked thread.

trevwhite · « **Reply #40 on:** December 16, 2019, 05:22:33 pm »

I think a Controleo3 might be able to control a setup. It seems to have some fancy profiling command set and also intelligent PID control. It seems very flexible and source code is open for any mods. Looks like a lot of work has gone into it. Anyone used one/can recommend?

https://www.whizoo.com/
Trev

wraper · « **Reply #41 on:** December 16, 2019, 07:12:40 pm »

Quote from: trevwhite on December 16, 2019, 05:22:33 pm

I think a Controleo3 might be able to control a setup. It seems to have some fancy profiling command set and also intelligent PID control. It seems very flexible and source code is open for any mods. Looks like a lot of work has gone into it. Anyone used one/can recommend?

https://www.whizoo.com/
Trev

Unless you write your own firmware, it won't work properly with vapor phase. It's nothing like controlling usual reflow oven. Simply slapping PID won't do the job. Given that you want proper temperature ramp. Not 100^oC PCB temperature and after 20 seconds solder already melted.

trevwhite · « **Reply #42 on:** December 16, 2019, 09:27:00 pm »

Hi, Wraper. Could you give a bit more detail on why it wont work? I know it's buried in the other thread but is there a link to the ideal profile for vapour phase?

I moticed the controleo even has a servo out. Might be possible to automate lifting the board up to help with cooling.

wraper · « **Reply #43 on:** December 16, 2019, 10:26:26 pm »

Quote from: trevwhite on December 16, 2019, 09:27:00 pm

Hi, Wraper. Could you give a bit more detail on why it wont work? I know it's buried in the other thread but is there a link to the ideal profile for vapour phase?

I moticed the controleo even has a servo out. Might be possible to automate lifting the board up to help with cooling.

Because you basically need to regulate height of vapor phase, not it's temperature.

trevwhite · « **Reply #44 on:** December 16, 2019, 10:40:23 pm »

So once vapour reaches the right height then its just about dropping power delivery to maintain the height or temperature. So I think that can be scripted in the controleo3. Phase 1 would be to heat it up and then once it reaches above a temperature, phase 2 would implement a second pid control specifically to maintain the temperature which would reduce the power delivery dramatically.

The last thing is how to cool the board down quick enough.

wraper · « **Reply #45 on:** December 16, 2019, 10:43:05 pm »

As of ideal profile, generally you should preheat PCB by some other means and then move PCB into chamber with vapor phase. What I've done and what this thread is about is making workaround by slowly rising vapor phase to preheat PCB by air and small amount of vapor above vapor phase. The issue is that when liquid reaches boiling point, vapor phase rises extremely fast and has a lot of heat capacity. But before it reaches boiling point PCB simply stays cool.

wraper · « **Reply #46 on:** December 16, 2019, 10:49:52 pm »

Quote from: trevwhite on December 16, 2019, 10:40:23 pm

So once vapour reaches the right height then its just about dropping power delivery to maintain the height or temperature.

It's will be somewhat controllable that way only if you place multiple temperature sensors at different heights. Also control is extremely laggy. It's not like you stop heating and vapor will stop to rise.

Quote

phase 2 would implement a second pid control specifically to maintain the temperature which would reduce the power delivery dramatically.

The problem with PID is that by time when it adjusts itself, solder is already melted. Basically you need to shut down heating even before vapor rises. Unless you want to heat with extremely small power extending reflow profile to unreasonably long time.

Here is what I've done with my oven

Quote from: wraper on January 01, 2017, 11:28:12 pm

RTD position was lowered by about 5mm but it still reads lower than temp on the PCB, and there is significant inertia. Right now it works like this (PID would be useless in this case):
1. Start heating
2. Once reached 80^oC, stop heating, wait 25s (after this PCB will be about 150-160^oC hot)
3. Heat 14s, likely a little bit more would be better, like 18s.
4. Stop heating, wait 25s (after this PCB will be about 180-190^oC hot)
5. Start heating
6. Once 195^oC is reached, stop heating and turn on cooling.

Here is profile. In volts, not temperature units but you get the idea. Not perfect but order of magnitude better than it was originally. As you see, I start cooling fans way before 230^o C reflow temperature is reached. Because I know that once I add a bit more heating, PCB temperature will shoot to max.

trevwhite · « **Reply #47 on:** December 16, 2019, 11:08:33 pm »

Thanks for the information. How long does the board sit at 230 or 240C? I think the paste profiles like it to be for at least 45 seconds.

wraper · « **Reply #48 on:** December 16, 2019, 11:14:41 pm »

Quote from: trevwhite on December 16, 2019, 11:08:33 pm

Thanks for the information. How long does the board sit at 230 or 240C? I think the paste profiles like it to be for at least 45 seconds.

There is no issue not staying long enough above melting point. The problem is cooling fast enough. Also with vapor phase you don't need to keep it under max temperature for long. All of the solder melts basically instantly everywhere. There is no such thing as heavier parts or large copper planes taking significantly more time.

trevwhite · « **Reply #49 on:** December 17, 2019, 02:42:47 pm »

I emailed Peter a bit who designed and makes the Controleo3. He has indicated that the profile language he created means that timers, wait for temp to be reached and ramp control can all be sequenced with his product. It seems the Controleo3 is not the typical reflow oven controller.

So based on Wraper's profile, is there much variation depending on the board size? I am thinking there must be some but maybe the vapour cloud has so much energy in it that there is capacity and one profile would do all boards.

Also cooling has been raised as important. Are fans blowing air at the pan proving good enough?


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