I have to agree with Jax. We've had some successes, and some horrible failures using white-tin. Generally in solderability, and apparently related to the somewhat more rapid deterioration of white-tin finishes.
We've run white-tin as an SMT only assembly, and when run off the shelf, have experienced poor solderability, that looks like it's caused by contaminated pads. Washing these same boards with isopropyl alchohol prior to assembly yields acceptable results.
We've also run white-tin on through hole only boards, with a much lower success rate. Soldering on a solder pot with white-tin finish produced an inordinantly high quantity of blow holes/pin-holes in our assembly. Those same boards run as ENIG boards produced much better results.
Our solution...always request ENIG finish on lead-free assemblies. As a CM, it's easier in general to develop one process that you know works, rather than mess around with processes that are questionable.
And, in response to why the board house gets blamed...well, as with any other element of the supply chain, when there's a problem, root cause needs to be examined. When, as Jax said, the root seems to be solder finish, and seems to be corrected by changing from white-tin to ENIG...well, then the corrective action becomes ENIG...for all like-elements...and that's regardless of the real issue, since the issue has been fixed by changing the board finish, why look any deeper.
cheers, ..rob
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