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July 2016 • The PCB Magazine 55 At one or more defined measurement points the reference standards are measured 25 times under repeatable conditions (one operator, nor- mal production measurement conditions). Re- sults are shown in Table 1. Capability Indices: Capability of the gauge: Nickel C g = (20% / 100% * 118.10) = 1.44 (2.742 * 6) Gold C g = (20% / 100% * 2.37) = 1.25 (0.063 * 6) Capability of the gauge, considering both the gauge accuracy and precision: Nickel: C gk = (20% / 200% * 118.10) - |180.54 - 180.00| = 1.37 ((2.742 * 6) / 2) Gold: C gk = (20% / 200% * 2.37) - |2.62 - 2.60| = 1.15 ((0.063 * 6) / 2) Results Gauge meets minimal acceptable capability indices of 1.00. Improvements should be made to achieve preferred capability indices of 1.33. Conclusion Assessing measurement capability is the first step in process control. The Type 1 Gauge study is an excellent technique for doing this. The ease of use and interpretation of results has been presented in this paper. Once measurement ca- pability is demonstrated, the process engineer and quality manager can systematically attack and reduce product variation. Variation reduc- tion is evidence of improved process control, and improved product reliability. PCB References 1. Automotive Industry Action Group (AIAG) (2002). Measurement Systems Analysis Reference Manual, 3 rd edition. Chrysler, Ford, General Motors Supplier Quality Requirements Task Force. 2. Bosch (2003). Vol 10 Quality Assurance in the Bosch Group Technical Statistics. Capability of Measurement and Test Processes. Robert Bosch GmbH. 3. Bell, S. (2001). Measurement Good Practice Guide: A Beginners Guide to Measurement Uncer- tainty (No. 11). United Kingdom: Crown. 4. A. Sleeper, personal communication, April 7, 2016. 5. Dr. E. Santiago, personal communication, April 8, 2016. 6. Christoph, R., and Neumann, H. (2006). Double Standards? Measuring Uncertainty in the Manufacturing Process. 7. Sleeper, A. (2012). Minitab 16 Demysti- fied. United States: McGraw-Hill. 8. Sandau, M., and Wisweh, L. (2000). Quali- ty Evaluation of Measurement Instruments. Pro- ceedings of XVI IMEKO World Congress, Austria. Patrick Valentine is manager of Six Sigma & business development for Uyemura USA. He can be con- tacted by clicking here. Table 1: Results of the 25 ENIG standards measurements. USING THE TYPE 1 GAUGE STUDY TO ASSESS MEASUREMENT CAPABILITY