Hi everyone,

As I remember it, in combined committee it was decided to leave copper as a final finish choice "when specified", for those rare occurrences that it is needed.

Robisan completely ignores the via (or other Cu) protection liability of OSP on bare printed circuits (e.g. when using 6010 series performance docs for conformance assessment).  But, after assembly all those surfaces shall have a final continuous finish of the solder alloy.  Or, be SMOBC (tent, complete double sided plug...).  

ImSn, ImAg as a "final" is a question for another day.  

SMOBC/OSP on compliant pin product (no wave soldering) sure scares me, but we've seen it in sealed assemblies.

We believe that unprotected bare copper in a hole has always been nonconforming per 6010 series and military specs.

The paragraph to which the nonconformance is attributed is plating and coating (final finish).  The quick answer to an argumentative fabricator is "bare copper is not a choice".  Some quality and designers understand this, but others do not.  Especially those who did not perform due diligence in reviewing the design for conforming fabrication (let's face it, most don't), and now have built (per the drawing, with let's say...single sided plug) a bunch of 6012 nonconforming product.

2221 is currently adding verbiage to warn designers.

And the question is: Does 6012 want to add a footnote to the bare copper finish "choice", or do we want our 1st explicit via protection paragraph?  Or leave it as is?  Honestly, once it's in 2221 most quality won't have trouble finding the basis.  But, just because it is completely contrary to 4761,  doesn't cut it (from our experience).

Just my take, your mileage may vary.

Chris

Chris Mahanna
Robisan Laboratory