مطالعه و بررسي شاخص قابليت فرآيند Cp در حالت چند متغيره با در نظر گرفتن خطاي ابزار اندازه گيري

چكيده انگليسي :

ABSTRACT Process capability analysis and have been widely used in the manufacturing industry formeasuring process reproduction capability according to its manufacturing specifications Oneof the methods for process capability analysis is indices Process capability indices have beenwidely used in the manufacturing industry for measuring process reproduction capabilityaccording to manufacturing specifications Properties of the univariate processes have beeninvestigated extensively but are comparatively neglected for multivariate processes wheremultiple dependent characteristics are involved in quality measurement In real applications manufactured products often have multiple quality characteristics and multiple characteristicsprocesses are by now so common that our studies to capability indices can t be restricted to theunivariate domain That is the process capability analysis involves more than one engineeringspecification For this reason multivariate methods for assessing process capability areproposed Since the quality of data on the process characteristics relies very much on thegauge measurement accuracy therefore the capability indices of the process by ignoring themeasurement errors would not be reliable So the gauge measurement capability has animportant effect on determining the process capability and this effect grows with increasing thegauge measurement error Any variation in the measurement process has a direct impact on theability to make sound judgment about the manufacturing process Conclusions about capabilityof the process without considering the gauge measurement capability are not reliable and ingeneral producers will be damaged if they ignore this fact We also claim that by consideringthe gauge measurement capability for estimating the process capability we get a betterestimation Consequently the more real estimations of process capability help the qualityexperts to adopt a better condition to improve the quality of the production In this paper we consider the effect of Gauge Measurement capability on the multivariateprocess capability index MCp Also with respect to measurement capability we investigatethe statistical properties of the estimated MCp and consider the effect of Gauge Measurementcapability on the lower confidence bound hypothesis testing critical value and power oftesting for MCp at the mentioned state Also we showed that the confidence coefficients maybecome insignificant and that the risk and the power of the test may decrease with asignificant magnitude due to gauge measurement errors resulting with too understatingcapability It could be a serious loss to the producers if gauge capability is not considered inprocess capability estimation and testing Since measurement errors may not be avoided having proper confidence coefficients and power becomes essential Thus we provided adjustedconfidence bounds and critical values for practitioners to use in determining whether theirprocesses meet the capability requirement The results of analysis show that GaugeMeasurement capability wills notability change the results of estimating and testing of processcapability With present adjusted confidence interval bounds and critical values for capabilitytesting purpose of MCp with unavoidable measurement errors we have suitable estimation andtest Our research would help quality experts to determine whether the factory processes meetthe capability requirement and make more reliable decisions

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مطالعه و بررسي شاخص قابليت فرآيند Cp در حالت چند متغيره با در نظر گرفتن خطاي ابزار اندازه گيري

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