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Gage R&R & Measurement System
Measurement Systems
Gage R&R studies per AIAG MSA; %GRR improvement and clearer calibration and measurement procedures.
Executive Summary
Measurement variation was consuming a large share of the tolerance. This project conducted Gage R&R studies per AIAG MSA, identified sources of variation (repeatability vs. appraiser), and improved calibration and method. Outcomes: %GRR below 30% for critical characteristics and clearer measurement procedures.
- %GRR < 30% for critical characteristics
- Clearer calibration and measurement procedures
- Data-driven gage replacement and training decisions
Context & Problem
Operators and quality disagreed on readings; capability studies were questionable because measurement error was high. The organization needed to quantify measurement system variation and reduce it where possible.
Methodology & Frameworks
The approach followed AIAG MSA: Gage R&R study (multiple appraisers, parts, trials); EV and AV estimated; %GRR vs. tolerance. Improvement actions targeted repeatability (gage, fixturing) or reproducibility (training, method).
Implementation
Gage R&R studies were run for key characteristics. Where %GRR was high, root cause was identified. Calibration schedules, procedures, and training were updated. Studies were repeated to verify improvement.
Outcomes
- %GRR below 30% for critical characteristics after improvements.
- Documented measurement methods and calibration records.
- Capability and SPC could be trusted once measurement error was under control.
Lessons Learned
MSA must come before capability and SPC. Distinguishing repeatability vs. reproducibility pointed to the right fix (gage vs. person). Periodic re-runs of Gage R&R kept the system in check.