Monitoring and diagnosing dependent process steps using VSI control charts

Autor:	Wan-Yun Chen, Su-Fen Yang
Rok vydání:	2011
Předmět:	Statistics and Probability Markov chain Control theory Applied Mathematics Numerical analysis SIGNAL (programming language) Process (computing) Process control Control chart Variance (accounting) Statistics Probability and Uncertainty Sampling interval Mathematics
Zdroj:	Journal of Statistical Planning and Inference. 141:1808-1816
ISSN:	0378-3758
DOI:	10.1016/j.jspi.2010.11.030
Popis:	The paper proposes the variables sampling interval (VSI) scheme to monitor the means and the variances in two dependent process steps. The performance of the considered VSI control charts is measured by the adjusted average time to signal derived by a Markov chain approach. An example of the process control for the metallic film thickness of the computer connectors system shows the application and performance of the proposed VSI control charts in detecting shifts. Furthermore, the performance of the VSI control charts and the fixed sampling interval control charts are compared via the numerical analysis results. These demonstrate that the former is much faster in detecting shifts. Whenever quality engineers cannot specify the values of variable sampling intervals, the optimal VSI control charts are recommended. Furthermore, the impacts of misusing Shewhart charts to monitoring the process mean and variance in the second process step are also investigated.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::f4eefc58009d84f980c9aba46da9d1d6 https://doi.org/10.1016/j.jspi.2010.11.030 Zobrazit plný text záznamu Full Text from ScienceDirect