Pete:

It has been several years since performing T&E's (as a contract lab), but
recall evaluating how the crosshead speed "over load" affects results.  I
cannot remember particulars, but I believe the speed was adjusted based upon
the thickness of the plated copper being tested.  As you inferred, slower
speeds can yield higher elongation results than faster speeds.

2.  Yes, this is true.  However, there were customers whom routinely
obtained better than 50,000 psi T and 20% E on their samples.  There were
others whom had consistently measurable differences between horizontally and
vertically prepared samples.

3.  I believe the pre-bake "anneals" the deposit, relaxing stress in the
crystal morphology of the copper deposit.  Testing samples before bake
yields higher T's and lower E's than after bake.

Good Luck,
ted

-----Original Message-----
From: Pete menuez [mailto:[log in to unmask]]
Sent: Thursday, January 27, 2005 7:37 AM
To: [log in to unmask]
Subject: [TN] Tensile Strength and Elongation Questions


Group:

I have a some questions regarding T/E I'm hoping someone can help.

1. IPC-TM-650  2.4.18.1A  paragraph 5.3.4.2 requires a Cross head speed of
between .05 - .5mm/mm (.00197-.0197 in/in) but does not specify the speed to
use in the test. It seems to me that the cross head speed could affect the
elongation values.  The slower the speed the higher the elongation.  Is
there any validity to my thought or does speed not make a difference?

2. Tensile strength and elongation have an inverse relationship.  Higher
elongation = lower tensile.  Is this true?

3. Paragraph 5.2 requires a Pre Test bake.  Why? Does this bake affect T/E?
What if the board shop also baked the sample for 4 - 6 hours - Would a
double bake have twice the affect.

Thanks in advance for any help.

pete

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