According to IPC-A-600, measling should not be the cause for a rejection
(2.3.1). However, when the measles become interconnected, it becomes
delamination.
Two questions I would ask you. Are you observing measling, or delamination
and what class of boards are you building to?
Any delamination that bridges between two conductors is nonconforming in any
class (2.3.2)
Any delamination that spans more than 25% of the distance between
conductors, but does not bridge between the conductors is non-conforming on
class 2 and 3.
Hope this helps you.

        ----------
        From:  Wynne, Derek [SMTP:[log in to unmask]]
        Sent:  Friday, April 07, 2000 10:40 AM
        To:  [log in to unmask]
        Subject:  [DC] PCB measling.

        Hi All,

          I have had an inquiry from one of our subcontractors re-measling
on
        several PCB's that they have just finished stuffing for us. They are
looking
        for detailed acceptance/rejection criteria. Our subcontractor states
that
        the IPC specification is a bit vague on this topic and by itself is
        difficult to generate acceptance/rejection criteria from.

         Do any of you specify acceptance/rejection criteria for measling on
PCB's,
        if so what are the criteria and how did you arrive at them ?

        I only have a copy of the early IPC-A-600, I am told that there is
more
        information in IPC-A-600F about measuring, so I will order that, but
in the
        mean time could someone please have a look at that standard and
forward me
        the relevant information. I would be very grateful as this is
delaying
        production for us.

        Thanks in Advance;

        Derek




        As I do not have a copy of IPC-A-600E