Vapour phase Soldering

[mrpackethead]

While everyone is converting toasters for DIY reflow, this guy

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?

[george graves]

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.

[jeremy]

This is from memory, so it could be completely wrong

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.

[mikeselectricstuff]

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

[mikeselectricstuff]

The other problem is there is only one manufacturer - Galden

AU$1850 for 5kg :
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

[jeremy]

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...

[ElektroQuark]

Anyone knows if those liquids are dielectric?

[coppice]

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,

[amyk]

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/reviews/professional-grade-reflow-ovens/30/

[mikeselectricstuff]

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.

[mrpackethead]

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.

[mrpackethead]

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.

[mrpackethead]

The other problem is there is only one manufacturer - Galden

AU$1850 for 5kg :
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

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.

[mrpackethead]

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!

[jeremy]

The other problem is there is only one manufacturer - Galden

AU$1850 for 5kg :
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

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

[mrpackethead]

Im sorry, its US$875.50. not $850.00  but close.

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."

[jeremy]

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?

[mrpackethead]

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

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.

[langwadt]

Anyone knows if those liquids are dielectric?

no isolation of the wires here: http://www.ibrtses.com/projects/vapourphasesoldering.html

[mrpackethead]

Anyone knows if those liquids are dielectric?

no isolation of the wires here: http://www.ibrtses.com/projects/vapourphasesoldering.html

It is a dielectric.

[jeremy]

Ok, I'm very interested. Anyone up for a group buy?

[ElektroQuark]

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.

[ajb]

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?

[IconicPCB]

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.

[jeremy]

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 tombstoning can be minimised by proper preheating.

If you do end up buying one, please sell me some galden!