Printed Wiring Assemblies (PWAs)
Excessive Staking

Excessive staking was applied over the leads of this quad-flatpack negating the stress relief incorporated in the lead bend. The result of this poor workmanship necessitated additional accelerated life test on the boards with the staking defects to characterize risk, as rework of the staking material would likely lead to part damage. This testing resulted in additional time and cost to the project.

Reference :
NASA-STD-8739.3,
4.3. Reliable Soldered Connections
1. Reliable soldered connections result from proper design; control of tools, materials, processes, and work environments; use of properly trained and skilled personnel; and careful workmanship.
8.1 General
1. Stress Relief. Stress relief shall be incorporated, wherever possible, into all leads and conductors terminating in solder connections to provide freedom of movement of part leads or conductors between points of constraint.

NASA-STD-8739.2
9.2 Staking
3. Staking Concerns. Caution must be taken to assure that:
a. The staking compound does not negate stress relief of parts and enclose joints, part leads, or mechanically compromise the reliability of the hardware.