A consumer electronics manufacturer sought out ACT to perform an assessment of a test set that was providing high reject rates in production. This test was used by its supplier for quality control in high-volume production of a thermal module. The test set was giving high reject rates for the production thermal modules. The consumer electronics manufacturer sought out ACT for both our expertise in manufacturing and quality control. ACT replicated the test set and repeated multiple series of thermal measurements on the thermal modules. ACT then performed a comprehensive Repeatability and Reproducibility study. ANOVA, Kolmogrov-Sminov, Pearson correlation and other key statistical parameters were calculated. The analysis showed reproducibility errors for the test set to be far higher than the generally acceptable 10-30%.
Instrumentation error was suspected because the products were rigorously tested in another, more controlled test apparatus and found to perform well. The root cause for the error was determined to be fixturing in the test set which permitted inconsistent thermocouple contact with the device being tested.
ACT recommended a systematic re-design of the test set. ACT also helped develop correlations for other test sets for different operating conditions. The client was extremely satisfied with the results from the projects and stated their process quality control has taken a significant step forward because of ACT’s contributions.