Gage R&R and SPC

Is my manufacturing process in Control? This seemingly benign question can be quantitatively answered through the use of Gage Repeatability and Reproducibility (GR&R) and Statistical Process Control (SPC) techniques. While almost all manufacturing processes include some form of quality measurement, the cost-benefit and efficacy of process changes can be difficult to quantify.

GR&R is essentially a measure of quality measurement variation, and SPC is a technique for controlling, optimizing and maintaining processes. While measurement equipment needs to be calibrated and tooling maintained, it can be expensive and time consuming to interrupt a process. GR&R and SPC techniques can facilitate data-driven decisions based upon quality metrics with known uncertainty, providing a clear linkage to value.

Achieving process control essentially boils down to understanding what can go wrong and monitoring quality metrics specific to the expected failure modes. This is relatively straight forward when there exists sufficient design for manufacturability (DFM) information from which to design an effective manufacturing process. In its absence, careful analysis and experience become critical to separating failure mode contributions into those rooted in measurement variation (GR&R) and those related to upstream vendor quality (SPC). Once in control, a SPC system monitors quality measurements for a statistically significant change and triggers an appropriate corrective action.

While most Fortune 500 companies embrace some form of the DFM-GR&R-SPC process methodology, many smaller companies struggle to identify a clear value-added proposition to justify the expense associated with widespread adoption. Furthermore, effectively integrating the three can prove to be a challenging combination of interdisciplinary skills no matter the environment and culture.

TCB Engineers has extensive manufacturing experience with consumer, medical, and DoD products. Having successfully brought many products through the release-alpha-beta-pilot model of transitioning projects to the manufacturing environment, TCB Engineers engages intuitively and creativity to find novel solutions.


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