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Higher TG for PWB when soldering Lead Free (?)

Gabriele

#27406

Higher TG for PWB when soldering Lead Free (?) | 27 February, 2004

Some literature recommand to increase TG of PCB when Soldering Lead Free (ie.SAC allow Reflow and Wave ), some literature do not mention it, some recommand it only in case of large panels, etc.

According to your experience,what is the best practice to consider ?

Tank you GLS

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Gabriele

#27407

Higher TG for PWB when soldering Lead Free (?) | 27 February, 2004

Some literature recommand to increase TG of PCB when Soldering Lead Free (ie.SAC alloy Reflow and Wave ), some literature do not mention it, some recommand it only in case of large panels, etc.

According to your experience,what is the best practice to consider ?

Thank you GLS

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Jay

#27539

Higher TG for PWB when soldering Lead Free (?) | 8 March, 2004

Sn-Ag, Sn-Sb, and Sn-Cu based lead free alloys have a higher melting point than that of Sn-Pb eutectic system. Thus, it will be better if you can use a higher TG PCB for lead free purpose.

But, also most of commercial products including SAC can be reflowed under 250C, which means you don't have to change PCB.

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Ken

#27554

Higher TG for PWB when soldering Lead Free (?) | 8 March, 2004

I have processed the following materials in lead free processes:

CEM FR1 FR4-120 FR4-140 FR4-170

Each material has different responses to thermal stresses. Issues to consider are: Panel size, smt only, wave only, double sided smt...and smt / wave hybred. You need to determine how these materials respond to YOUR process...as we do not know what your process is and what widgets you make. Example: Do you use odd form placement or auto Thru hole insertion? Then panel warp will be a priority for you. Do you TH insert, cut/clinch single sided wave only? Selective pallet in wave or board on chain? ...million variables....million answers

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