Meaning
A statistical evaluation method determines the amount of variation in a measurement system arising from device repeatability and appraiser reproducibility. Utilizing a gage r and r study allows quality engineers to isolate the noise of the test equipment from the actual process variation. This analysis applies directly to the testing of RF modules, antenna return loss, and board thickness.
Variance Decomposition
Total observed variation combines part-to-part differences with measurement error. Here, repeatability represents the equipment error, while reproducibility represents operator variation.
Testing Protocol
Executing the study requires multiple operators to measure a set of identical parts several times in a randomized sequence. For example, three technicians might measure ten separate antenna boards three times each. Blind testing ensures that operators do not bias their readings based on previous results.
Acceptance Criteria
Standards like those from the Automotive Industry Action Group defines the thresholds for a capable measurement system. An error below ten percent is ideal, while an error up to thirty percent is marginally acceptable for non-critical dimensions. Any gage r and r result above thirty percent indicates that the measurement system is inadequate for production monitoring.
Redesigning the test fixtures or retraining the operators must occur before resuming official certification scans.
