Economically Optimal Determination of the Parameters of np-Control Charts

Abstract

Two production models are presented for maintaining current control of an industrial process under the surveillance of an np-control chart. The formulated cost function includes the cost of maintaining an np-control chart, search for the assignable cause, downtime, higher rate of defective items, and repair. Two models are formulated. The first model assumes that the process is not allowed to continue in operation during the search for the assignable cause. The second assumes that the process is allowed to continue in operation during the search for the assignable cause. A simple search procedure is developed for determining the optimal parameters of an np-control chart that minimize the cost function. Illustrative examples show how the formulated models can be applied.

• Cost Functions
• Economic Design
• np-Control Charts
• Process Control Optimization

Additional information

Notes on contributors

Isaac N. Gibra

Dr. Gibra is professor of Operations Research and Management Science at Stevens Institute of Technology. He is a senior member of ASQC.