Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

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SMT electronics assembly manufacturing forum.


Solder paste working life

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E.K.

#62320

Solder paste working life | 26 July, 2010

When hand placing SMT components what is the working time before the solder paste become unusable (dry)?

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#62321

Solder paste working life | 26 July, 2010

It depends. Read "Evaluating Solder Paste - not an Option" by Phil Zarrow, ITM Consulting

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#62326

Solder paste working life | 27 July, 2010

You have to figure this out for yourself for your paste. When I evaluate solder pastes I require good tack, no solder balls, and proper wetting after 4 hours at "reasonable" ambient conditions. I also print boards and put them in a temp/humidity chamber for 1 hour (or 1 hour in a shady spot outside on a humid day) before placement & reflow and expect good performance.

Don't ask the paste supplier - they'll tell you it can sit all day. You need to get your own data.

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