Good morning all:

Classic reliability models define categories of failures:
*  Infant mortality:  occurring within weeks of assembly; measured in
Defects Per Million Opportunities (DPMO); caused by failure of:
components, wire/harness connections, board solder connections, and
board vias.
*  Random failure:  occurring over the operating life of a product;
measured in Failure In Time (FIT).
*  End-of-life failure:  measured in time or thermal cycles; caused by
temperature cycling, mechanical wear, degradation of materials, and
fatigue.

What would you specify for rates of:
*  Infant mortality for circuit board solder connections?  Board vias?
Wire harness connections?
*  Random failure mortality of circuit board solder connections?  Board
vias?  Wire harness connections?
*  End-of-life wear-out mortality for circuit board solder connections?
Board vias?  Wire harness connections?

How do you measure these rates?

Do you have base data of failure rate information of components?

How would you suggest to screen boards and wire harness for infant
mortality?  What Delta T can use use for accelerating stress?  How many
temperature cycles do you suggest for such screening?

What needs to be considered in figuring the cost (production and NRE) of
such screening?

What needs to be considered in figuring the production lead time issues
relating to such screening?

Thanks

Dave Fish

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