Abstract
In today’s highly developed manufacturing industry, Process capability indices (PCIs) are effective means of measuring process performance. Most process capability indices have been developed under the assumption that the quality characteristics are normally distributed. However, the lifetime of electronic components generally may possess an exponential, gamma or Weibull distribution and so forth. A lifetime performance index CL was proposed and used as a means of measuring product lifetime performance. The lifetime of products is a larger-the-better type quality characteristic and is generally required to exceed L unit times. Acceptance sampling plans provide the producer and the customer a general decision rule for lot sentencing that meets both of their quality and risk requirements. This thesis attempts to introduce two variables sampling plan for product acceptance determination based on the lifetime performance index. One is developed under the exponential complete data; the other sampling plan is developed under gamma complete data. The probability of acceptance, i.e., the operating characteristic function of the proposed sampling plan, is derived based on the exact sampling distribution of the estimator of the lifetime performance index. The required sample size n and the corresponding critical value k are determined by solving two non-linear equations simultaneously. Furthermore, a comparison study is also conducted to compare the proposed CL based sampling plan and the existing sampling plan. And for the practical purpose, this study tabulated the plan parameters for various combinations of acceptable and rejectable quality levels, producer’s risks and consumer’s risks. Thus, practitioners can easily understand the number of product items required for inspection and the corresponding critical value for making decisions on product acceptance determination. Finally, an application is given for illustration.