Advanced Tolerancing Based on Product Performance by Using Statistical Tolerance Index Cpk and Cc

In this paper, the improvement of performance design for mass production are shown by using statistical tolerance index C-pk and C-c. Recently, the demand for product performance is getting higher. Meanwhile, precision machining and measurement are also developing in manufacturing industry. To satisfy consumer in terms of product performance, we have proposed advanced tolerancing method by using statistical tolerance index (STI). In this study, it is assumed that the performance of each product can be quantified and depends on the only functional dimension. It is also assumed that the dimension distribution of each machined part follows normal distribution. Consequently, performance of mass production can be quantified statistically. To control performance, we introduce STI which is composed of process capability limitation. After all, performance design is to calculate STI so as to satisfy the demand for performance. There are two problems in performance design. One is a synthesis of STI and another is an allocation of STI. These problems are just like the conventional tolerance synthesis and allocation problems. In this paper, the former problem is formulated algebraically.