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ImSn thickness

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GS

#47709

ImSn thickness | 16 February, 2007

Hi,

questions about PCB ImSn finishing :

a) how much is the standard thickness (most common)?

b) how much is the maximum thickness obtainable by this finishing process?

Thank you

Regards....GS

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#47711

ImSn thickness | 16 February, 2007

Good afternoon,

Typical plating thickness for immersion tin is 0.6-1.0um. I do not know what the maximal thickness is. But plating is self-limiting process and I believe maximal thickness should be about 2-3um.

BR, Pavel

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#47744

ImSn thickness | 16 February, 2007

IPC-4554 Specification for Immersion Tin Plating for Printed Circuit Boards

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GS

#47826

ImSn thickness | 19 February, 2007

Thank You Pavel and Dave,

Unfortunately I do not have IPC-4554.

Anyway I 0.6-1.0umm is what I remember, and confirmed by reading also through leterature available on google.

I was just going to understand if it possible to obtain more thickness even if it seams the process is complex.

It was a discussion among friends, where they say that in order to avoid tin oxidations (due to IMC moving on surface, etc ) after first SMT or Second SMT pass before THT wave, to increase Tin thickness could help to avoid unwetting problems and improvo vertical fill :)

But I think ( not alone)that ImSn is not a good finisch in case of L-F soldering more then one SMT side/pass and THT.

Tnks

Best Regards...GS

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