77Chapter four: Current issues in reliability technology
steel to powdered metal—a completely different structure—reliability
engineers thought the existing specications would still be appropriate
to test compressors incorporating these new, cost-saving materials. The
large number of test samples, perhaps, made them comfortable about reli-
ability, but the resulting failures within a year indicate that the existing
test specications, anticipated to prove at least 5 years of operating life,
were completely inapplicable for the new compressors. This highlights
the importance of conrming the validity of reliability test specications,
as described above in the rst condition.
Company M’s refrigerators experienced epidemic failures ov ...