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| From [log in to unmask] Tue Jun 18 13: |
58:25 1996 |
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Paul.
If I understand your process, you are only going to use tin as an etch resist
and strip it and go SMOBC
A supplier down in Conn., MacDermid, sells a tin electroplate formulation
used mainly for your type of process and is one of the cheapest based on a
tin sulphate bath. You will find the tin stripping easier and faster than
the tin/lead. Obviously, after etching don't fuse it and don't use
solderbright. The plating is pretty normal and you can convert your tin/lead
process and pre-tin/lead pickle using the same process line and change the
acid predip accordingly.
The tin thickness minimum is about 0.0003 inch, but to be safe a 0.0005 is
often used.
Your process removes all of the tin plating and you are not concerned with
whiskers, slivers and gray tin. If you are going to use the tin as a final
finish, put another note on technet and I can furnish additional information.
Phil Hinton
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