Technical note: reduction of measurement variation, small acoustic chamber screening of hard disk drives

摘要

Small acoustic chambers on the manufacturing floor are used at some disk drive manufacturers to screen out unacceptably loud disk drives. To be effective, screening tests must give accurate and consistent results. When small acoustic chambers were installed at Western Digital's manufacturing facility, they initially had large variations. These sound measurement variations were unacceptable. In this study the most significant sources of variation were identified using Analysis of Variance (ANOVA) techniques and a design of experiment (DOE) approach. The most significant factor was found to be the microphone calibration. The statistical test methodology proved to be an efficient way to study and improve the repeatability of these small acoustic chambers.