We have a great deal of experience in using ‘HALT’ stress screening, and other reliability
enhancement techniques, to significantly improve product reliability via simple,
inexpensive and minor design changes.
One example relates to a new industrial control product that was to be a replacement
for an earlier model that had reliability problems.
The application demanded high levels of reliability, and there was concern that the
new product may not be sufficiently better than its predecessor.
Our experience includes
Reviewing the design
Looking at an early prototype and identifying areas for improvement, mostly in the
area of cooling and mechanical fixings
Devising and managing the process of Highly Accelerated Life Testing (‘HALT’; a type
of stress screening that helps you to improve the design’s robustness)
Through this process, identifying weaknesses in the ventilation system and mechanical
support within the unit and devising easy and inexpensive improvements
Changing the ventilation system, providing mechanical support for some of the components
and cables, and introducing specific torque settings and anti-vibration measures
to the fixings
Re-testing of the revised prototypes to prove their much higher robustness to stress;
the failures we had previously seen at high mechanical shock levels, and at combined
temperature extremes and modest shock, could no longer be induced, and by using this
technique it would mean greater reliability under normal conditions of use.
The new design was introduced into volume production and showed a five-fold improvement
in reliability compared with its predecessor.