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White tin pcb, smt production

David Bratcher

#32953

White tin pcb, smt production | 1 March, 2005

What thickness is required to process a double sided board with white tin? Is there an IPC standard? If rework is necessary, what is required?

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#32963

White tin pcb, smt production | 1 March, 2005

IPC Plating Committee is presently working on a specification for immersion tin [IPC-4554 Specification for Immersion Tin Plating for Printed Circuit Boards] as a solderable surface finish. Immersion tin is normally deposited at 30 to 60 microinches. Look here: http://www.ipc.org/status.asp

Some people prefer immersion silver over immersion tin, because of the higher temperatures requried by immersion tin.

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#33054

White tin pcb, smt production | 5 March, 2005

You can also try the Florida Circtech website or call them direct. There is a min. thickness requirement and if the board house does not follow it you will end up with scrap boards after the second pass (from experience). I even sent blank boards to Florida Cirtech and they were able to measure the thickness (results were it was under spec)...we've since scratched the pcb supplier from our vendor list. I agree with dave, immersion silver might be a better way to go given the immersion tin limitations on number of heat cycles directly related to finish thickness.

Gus

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