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Lead free compatibility

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Lead free compatibility | 5 December, 2005

Anyone with definitive reliability data on mixing thru hole lead free terminations (SAC and Sn/Cu) with Sn/Pb solder.

Seems like a lot of conflicting information

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Lead free compatibility | 5 December, 2005

I hate to sound like a broken record but the industry has been placing lead free through-hole parts forever. Now all of a sudden its a problem???

Gold finish, silver, silver paladium, alloy 42, even pure copper. Reliability will be a function of the components you select, its metals composition IN ADDITION to the solder alloy.

Example: I had two identical 20 pin through hole connectors. One was white plastic one black. Every other feature was identical (so I thought). Fillet cracking was observed on the white component. It was never observed on the black component. This product was transitioned from tin/lead to lead free and both part numbers had MILLIONS of placements with no record of fillet cracking (during manufacturing).

Used in tin/lead = no problems. Used in lead free = fillet cracking.

Turns out the problem connector was using a different pin alloy than its cousin. cte mismatch was the root cause.

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Samir Nagaheenanajar


Lead free compatibility | 6 December, 2005

I agree with Ken!! Amen to that, brother! At my company here in Rihad, our design guys are in a tizzy about lead free components and tin whiskers, and with every questionable through-hole solder joint, or when our purchasing department gets "notified" from a resistor manufacturer that they have switched to a "RoHS" compliant device with a a common plating such as Ni-Pd, which has been used on TH for many years (as far back as the '80s), the design guys panic and start screaming tin-whiskers and they tell purchasing to put the components on "hold." Aaaagggghh... makes me want to chop their hands off!

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