Joe
I have seen many microsections in years passed where the plating was stuck to
the inner layers only and none to the laminate.  Inner layers must be
attached.  Military specs still have a resin recession requirement "as
received".  IPC specs evaluate after stress and therefore have dropped the
consideration that resin recession is a defect.

The theory being if there is no requirement after stress, then why have a
limit before?

Inner layers must be attached.

How do you know the hole wall "explodes" or "delaminates" after HASL?  Is
this by microsection or visual assessment?

Susan