Hi Ralph,
Being I used to be the Quality Manager for a laminate manufacturer and I currenlty purchase and consume a lot of laminate I can offer an opinion. The processes used to manufacture the mil spec laminates and commercial products are not different. The product itself is not different. It is only inspected closer at a higher cost. I do not consider the quality of the products produced to be any different since there is not difference in the process.
However, I have run into some issues related to how you order it.
Mil-S-13949 was ordered core plus copper regardless of thickess. A very simple approach. Today , unless specifically stated and inspected for, most of the time you will get laminates under .031 thick core plus copper but laminates .031 and over the copper will be included in the overall thickness.
Todays laminates are very good products regardless who you buy them form. It has been a very long time since I've had a reliability issue in the field that was related to the base laminate.
Just my two cents.
Ed Cosper
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From: Vaughan, Ralph H
Sent: Tuesday, December 01, 1998 3:24 PM
To: [log in to unmask]
Subject: [TN] IPC-4101
Hi Folks,
I'd like to get a read from the laminate formulators, PWB shops, and other
assemblers (like myself) as to the perceived impact of IPC-4101 replacing
Mil-13949. I have seen charts of the differences between the two, and, as
minor as they seem to me, there are some out there (esp, DSCC) that have
real concerns that the door will be opened for the production of
sub-standard hardware.
Are board shops going to specify 4101, with additional testing specified,to
ensure the quality remains consistent with the Mil-spec material, or should
we be comfortable with 4101 as-is, and regard 13949 as overkill in the
testing dept.? How are you, as the buyer and user of the laminate material,
going to be satisfied that you are providing your customers the same high
quality boards as before?
Thanks for your opinions.
Ralph Vaughan
Boeing-Atlanta
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