I believe the standard is a guideline, but defined ENIG at that time with those specifications for thickness.

However, any company can put any specification they feel is appropriate for plating, plating thickness, etc, on their PWB fabrication drawing if they feel it is appropriate for the specific product and product use environment. This is usually handled AABUS. It can also be handled through the use of a deviation or waiver.

Your company's PWB fabrication drawing notes, assembly drawing notes, BOM, schematic, and any waivers or deviations take precedence over all other technical specifications, standards, etc, except for possibly legal requirements such as local environmental standards, etc.

So if you decreed .4 microns on your fabrication drawing, or if you allowed it as part of receiving inspection requirements and/or product MRT/MRB disposition, and the plating was in fact .4 microns minimum and not less, you were fully compliant to your own Technical Data Package. You did not ship anything that did not meet your requirements AABUS.



-----Original Message-----

From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Showers

Sent: Monday, April 30, 2018 8:15 AM

To: [log in to unmask]

Subject: [TN] Interpretation of IPC-4552A (ENIG Thickness)



I am asking that anyone who is an appropriate authority on IPC-4552A to chime in on the new standard.



Clarification 1) The ENIG process min is still 0.5 microns (2 uinch) expect for the following exceptions:

1) An allowance in the Procurement documents (PO, fab prints/notes) down to 0.4 microns [ For that matter, I can write my fab documents to allow for anything ].



Clarification 2) I have always allowed for readings down to 0.4 microns when inspecting as to allow for process and measurement variation.  Previously this could have been rejected for by IPC-4552.  Is this now acceptable?  That is, is what I used to do out of necessity and to prevent rejection of usable product, now an allowance of the standard?