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SMT electronics assembly manufacturing forum.


Temperature & Humidity Effects on Solder Paste

Aaron Delfausse

#15000

Temperature & Humidity Effects on Solder Paste | 16 July, 1998

My question is in regards to how exactly temperature and humidity affect the stencil printing process. If temperatures here at the plant in the summer are 70-73 degrees F. and relative humidity is 60-65%,to what extent will the results of the stecil printing process vary? Can I expect a significant difference? Have their been any studies done on the effects of slight changes in humidity and temperature? Thanks.

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Justin Medernach

#15001

Re: Temperature & Humidity Effects on Solder Paste | 17 July, 1998

| My question is in regards to how exactly temperature and humidity affect the stencil printing process. If temperatures here at the plant in the summer are 70-73 degrees F. and relative humidity is 60-65%,to what extent will the results of the stecil printing process vary? Can I expect a significant difference? Have their been any studies done on the effects of slight changes in humidity and temperature? Thanks. Aaron, The effects of environment can be significant or nonexistant. It depends on your paste. Are you No Clean, RMA, water soluble...??? Who's do you use? Have you conducted tests? There is no simple answer to this question. Water soluble stinks in humid environments. NC is good environmentally but as far as process is concerned, it can bite the big one. RMA is the most resiliant but requires "nasties" for effective cleaning. Be a little more specific as to what type of paste you're using and I'll be able to help further and give you some good test vehicles. Regards, Justin Medernach Flextronics International

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Aaron Delfausse

#15003

Re: Temperature & Humidity Effects on Solder Paste | 17 July, 1998

We currently use an ESP RMA paste. The reason that I initially posted the question was because we are conducting tests to see if this is infact the best paste for our processes. In running tests, however, certain variables, such as humidity, are out of our control. We may print one paste at 60% RH and another at 65% so I was wondering how the pastes we are evaluating would react to these varying conditions. The other pastes being tested are: Alpha RMA390DH3 Kester R253NC Qualitek Delta 230 RMA Thanks, Aaron

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Justin Medernach

#15005

Re: Temperature & Humidity Effects on Solder Paste | 20 July, 1998

| We currently use an ESP RMA paste. The reason that I initially posted the question was because we are conducting tests to see if this is infact the best paste for our processes. In running tests, however, certain variables, such as humidity, are out of our control. We may print one paste at 60% RH and another at 65% so I was wondering how the pastes we are evaluating would react to these varying conditions. The other pastes being tested are: | Alpha RMA390DH3 | Kester R253NC | Qualitek Delta 230 RMA | Thanks, | Aaron Aaron, Gotcha. You are still going to need to heed what I said. RMAs are resistive to environment but not as resistive as no-cleans. The no-cleans have a whole host of other process related issues. At the top are pin testability and solder balls. I would stick with the RMAs. Check out the AMTEC RMA223. It's a nice RMA. You might be impressed. I was. I have a controlled environment though so that might be the difference. Water solubles definitely aren't in your bag, especially without environmental controls. Regards, Justin Medernach

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Russ Miculich

#15004

Re: Temperature & Humidity Effects on Solder Paste | 24 July, 1998

The variance of useability of any of the pastes with a difference of 5% in your overall environment will probably not even be measurable in the difference of the paste be it RMA, Water Soluble, or No Clean. What is the printer you are using and is it enclosed or open to your current working environment? If you have climate control in the manufacturing floor area you will not have to worry about environmental control on the printer. If you can live with the tighter reflow profiles for epoxy based no cleans, that would be my recommendation. | We currently use an ESP RMA paste. The reason that I initially posted the question was because we are conducting tests to see if this is infact the best paste for our processes. In running tests, however, certain variables, such as humidity, are out of our control. We may print one paste at 60% RH and another at 65% so I was wondering how the pastes we are evaluating would react to these varying conditions. The other pastes being tested are: | Alpha RMA390DH3 | Kester R253NC | Qualitek Delta 230 RMA | Thanks, | Aaron

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Claudio Carnevali

#15002

Re: Temperature & Humidity Effects on Solder Paste | 1 August, 1998

I can explain my experience. I had a no clean paste and in summer I had a lot of problems. Now I have installed and air cooling system and I work with 25�C and 50-55%. I think you'll have less problems but smt problems usually doesn't have only one answer. If you want further informations don't hesitate to write me. Best RGDS

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