| Autor: |
Lee, Ming Ha, Khoo, Michael B. C., Haq, Abdul, Wong, Dennis M. L., Chew, XinYing |
| Zdroj: |
Quality Technology and Quantitative Management; March 2023, Vol. 20 Issue: 2 p168-183, 16p |
| Abstrakt: |
ABSTRACTIn statistical process control, the total number of nonconformities per unit of a process is monitored by using the cchart. In this study, the run length performance of the synthetic cchart with known process parameter (denoted as the KP-Syn-cchart) and the synthetic cchart with estimated process parameter (denoted as the EP-Syn-cchart) are evaluated in terms of the median run length (MRL). The results show that the sensitivity of the MRL-based EP-Syn-cchart is dependent on the number of preliminary samples used in the Phase-I analysis. Furthermore, percentiles of the run length distribution are used to provide a better understanding for the run length performance of the EP-Syn-cchart. The numerical analysis shows that the required minimum number of preliminary samples can be very large for the MRL-based EP-Syn-cchart to perform similar as the KP-Syn-cchart. An optimization procedure is suggested to compute the design parameters of the EP-Syn-cchart by minimizing the out-of-control MRL. Furthermore, the optimal design procedure of the EP-Syn-cchart is also provided through minimizing the out-of-control expected MRL for the unknown process shift size. An example is provided to illustrate the design and implementation of the MRL-based EP-Syn-cchart. |
| Databáze: |
Supplemental Index |
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