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environment Operational deg-C and RH% for Paste Printer

ianchan

#20245

environment Operational deg-C and RH% for Paste Printer | 6 June, 2002

Hi mates,

does anyone know if there is a industrial standard spec for environment(deg-C, RH%) operational use of Paste Printer machines?

If there is no study to define a deg-C, RH% specs for immediate environemnt operation use of a paste printer machine... what about a spec for the "surface-area" of a typical 10,000 sq-foot SMT production floor?

would appreciate everyone's help here, as we are updating our QA/process plan for an aerospace product build, and the customer was asking about such (deg-C, RH%) specs? we took it further to be based on the Paste Printer machine operation as we view deg-C, RH% to be critical for the solder paste printing.

thanks in advance for everyone's advice :P

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Hussman69

#20258

environment Operational deg-C and RH% for Paste Printer | 6 June, 2002

We based ours on the type of paste we use (stencil life) and not so much the machine. Then we coupled that to what 'true' conditions we normally see in our plant, and determined that under these conditions Max & min) our printing process should be good for so many hours. We also broke it down to how long a printed board can stay idle on the line for both placement conditions and reflow conditions. Our paste company helped us out. Just be sure to have a detailed spec on your paste and a log on how you determined your temp and RH. I can't tell you how many times ISO and QS auditors ask for it.

One thing to consider is your other processes at this specified temp and RH. We once had to show an auditor that our specified temp/RH for the screen printing operation was not affecting our conformal coating process. His tie must have been a little looser than I thought.

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#20259

environment Operational deg-C and RH% for Paste Printer | 6 June, 2002

Most paste supplier recommendations seem to work fine in the locale of the printer.

Search the fine SMTnet Archives for recommendations on the range of control for temperature and humidity in a assembly shop.

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Dason C

#20264

environment Operational deg-C and RH% for Paste Printer | 6 June, 2002

It is normal recommended by the paste supplier. Indium paste claim that it can worked on high temp/RH area.

Also, check Aim solder web site and they have a good solder paste handling guideline.

Internally, we control our environment not exceed 27C and humidity between 30~60% else production should stop.

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ianchan

#20267

environment Operational deg-C and RH% for Paste Printer | 6 June, 2002

Hi mates,

1) Firstly, thanks for everyone's reply to this thread. Cheers!

2) Secondly, Hussman69: sure u dun mean that blokes' tie was too tight? musta cut off his blood flow and oxygen?!?

3) Thirdly, we checked with our paste supplier, and they recomend 23-25 deg-C operational temperature. we set it to 22-26 deg-C specs. humidity is set 40-60RH%.

4) we were wondering how to answer auditor "technical" questions, hence this posted thread. we narrowed down via logical deduction paste specs is the primary factor, followed by heat "generation" from the machine, lastly with consideration of usage life of the paste on the Stencil.

seems its all how we answer eh? abit like back in school. lotsa smoking...

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Hussman69

#20281

environment Operational deg-C and RH% for Paste Printer | 7 June, 2002

Nope, too loose, allowing blood flow because he actually asked a logical question. Most times they ask me a question like "How does the heat generated from your screen printer affect the process of your wave solder?". I would generally answer it doesn't affect it, but then they smile like they got you. It always seems you always have to prove your answers, even for the most ridiculous questions.

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