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Date: | 29 Jul 1997 09:13:46 -0500 |
Content-Type: | text/plain |
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At the recent IPC meeting in Tempe, AZ. on IPC 6012, Qualification and
Performance Specification for Rigid Printed Boards, I asked if Para 3.11.8
b), which reads as follows, is realistic given todays thicker boards and
higher aspect ratios:
b) When tested as specified in IPC-TM-650, method 2.4.18.1 ambient
using 50-100 micrometer (0.002-0.004 in) thick sample, the tensile strength
shall be no less than 245MPa (36,000 psi) and the elongation shall be no
less than 6%.
The numbers appear to be directly from WS 6536 and unchanged over the years;
I personally do not think a 0.125 board with 16 mil holes if it were 6%
elongation would be very reliable. I also do not think anyone really would
try to be at 6%. BUT I have no data so when I said why not change to a
"real" number , the team members said show me the data. That leads me to
ask the following; anybody have any data? Is a value of 49,000 psi and 14%
, any better , or any worse, than a 42,000 psi and 22%?
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