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Tue, 5 Dec 1995 12:47:28 -0600 |
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| From [log in to unmask] Sat Apr 27 15: |
25:34 1996 |
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I sent this to the wrong address - apologies.
What laminate are you using? I have some data on the Z-axis
expansion of several common laminate material. My company was
recommended to go with the following speicfication for FR-4 on a Flight
compatible piece of hardware: Use HTE (ehich is class 3) copper foil
for conductive layers, 1.5 micron PTH wall thickness of copper with
12-30% elongation, 45k-55k PSI tensile strength. Some also specify a
Nickel coating on the PTH barrels after copper plating for strength
although we were assured that this was not necessary. This is a common
specification in the aerospace industry where the product experiences
large and frequent temperature cycles. The above spec was developed
for a new laminate material called Non-Woven Aramid.
Martin Kennett - Design Engineer, SED Systems Inc, Saskatoon, Canada.
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