PROCESSES CONTROL FOR TWO FAILURE MECHANISMS

ABSTRACT

This paper considers the economic statistical process control for two dependent processes with two failure mechanisms which obey Weibull shock models and have increasing failure rates. We construct individual economic statistical X control chart to monitor the in-coming quality produced by the first process, and use the cause-selecting control chart to monitor the specific quality produced by the second process with minimal cost and required statistical properties. By using the proposed control charts, we can effectively and economically distinguish which process is out of control. The renewal theorem approach is extended to construct the cost model for our proposed control charts, and optimization method is used to determine the optimal design parameters of the proposed control charts. Finally, we give an example to show how to construct and apply the proposed control charts.

Keywords:

• processes
• weibull distribution
• control charts
• renewal theorem