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Vapour phase Soldering

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Kjelt:

--- Quote from: jeremy on January 24, 2015, 01:57:57 pm ---Now I'm trying to think about how to raise the board gently when potentially the balls are still liquid. 
--- End quote ---
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.


--- Quote from: jeremy ---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!
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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.


--- Quote from:  mrpackethead ---PDF attached,  what do you make of this.. Is this a marketing thing, or is this for real.
--- End quote ---
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.

jeremy:

--- Quote from: Kjelt on January 26, 2015, 08:53:47 am ---
--- Quote from: jeremy on January 24, 2015, 01:57:57 pm ---Now I'm trying to think about how to raise the board gently when potentially the balls are still liquid. 
--- End quote ---
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.

--- End quote ---

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.

Kjelt:
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.

jeremy:

--- Quote from: Kjelt on January 26, 2015, 09:55:49 am ---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.

--- End quote ---

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)

mikeselectricstuff:

--- Quote from: jeremy on January 26, 2015, 08:05:46 am ---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.


--- End quote ---
Lower viscosity - better run-off from the PCB?

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