AN ECONOMIC DESIGN OF TUKEY'S CONTROL CHART

ABSTRACT

The significant features of Tukey's control chart include characteristics such as: easy setup, use of single observation to monitor process, and suitability to monitor destructive testing processes. The control limit width and sampling interval should be determined before Tukey's control chart can be used. In this study, Duncan's cost function is modified to construct an economic design model of Tukey's chart and to attain optimal design. Furthermore, methods of calculating error probabilities of Tukey's chart under normal conditions are constructed and applied in the economic design model. A real-world example of IC packaging illustrates the application of Tukey's chart to economics. The results of sensitivity analyses demonstrate that shorter in-control time or larger process variation cost incurs higher control cost.

Keywords:

• Tukey's control chart
• economic design
• inter-quartile range
• box plot