We are discussing the maximum number of rework cycles that an assembly can
withstand before being considered a reliability risk.
Historically we have always used five rework cycles as our guideline which
permitted the part to be taken off, and put on twice during rework.

1.  Reflow oven exposure
2.  Removal cycle
3.  Resolder cycle
4.  Removal cycle
5.  Resolder cycle.

The first question is where does this requirement actually come from and
the answer usually is give based on the standard coupon float testing.

But in today world, with one piece shields incorporated, such a simple
approach is usually not the case.

1.  Reflow first side oven exposure
2.  Reflow second side oven exposure
3.  Remove shield cycle
4.  Remove part cycle
5.  Resolder part cycle
6.  Resolder shield cycle
7.  Remove shield cycle
8.  Remove part cycle
9.  Resolder part cycle
10.Resolder shield cycle

Comments anyone?

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