Immersion Tin

We just went through a difficult time processing SMT immersion white tins PCA's and found the following: 1. FAB vendor had a degraded tin solution resulting in improper plating thickness 2. FAB vendor was not using the proper cleaning process

Get someone that knows the process to audit the FAB vendors process. Once they clean up their process, you should have good results.

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Celiav: Mark is probably spot-on on his comments about a board fab problem. It is weird that you have similar problems from two suppliers though.

Recommendations are: � Get rid of any bird brain contractor that installs processes that affect your product quality without notifying you and demonstrating the control, effectiveness, and effectivity of the new / changed process. � Assuming you have to clean-up this mess before you can get rid of those jerks, steps to better understanding the situation are: - Determine why your suppliers are not performing incoming solderability testing on these boards to demonstrate their suppliers� process control. It seems particularly coocoo that they don�t know these boards will not solder until they get so far down-stream. - Establish the appropriateness and compatibility of the solder and flux used by your suppliers with the solderability protection on the boards. - Understand the process controls used by the board fabricator(s). Since immersion tin, like HASL, is not a plating process (something that fabs understand), it requires process control unlike their plating controls. - Two companies [ie, Dexter, Florida CirTech (Omicron)] license immersion tin technology to fabricators. Get the appropriate licenser involved. It will be difficult to determine who is less please about this: you or them.

Finally, it�s fairly disturbing that your suppliers are so technically inept that you are forced into assisting them in solving this problem. I assume, availability of technical skills is among the reasons that you decided to use an out-side supplier.

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