Economic designs of attribute control charts for multiple assignable causes^*

^*This research was supported by the National Science Council of the Republic of China.

Abstract

In 1981, Professor Isaac N. Gibra presented two production models for maintaining current control of an industrial process subject to a multiplicity of assignable causes. The first model allows for shutting down the process 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, In this article, we develop two simple and explicit equations for v (sampling interval) in terms of n (sample size) and c (the acceptance number) for the two models, respectively. We conclude that our models are not only more accurate, more applicable and more flexible, but also simpler to solve than Gibra’s models.

Keywords:

• Economic design
• attribute control chart
• multiple assignable cause
• process control

AMS 1980 Subject Classification:

• Primary:62 N 10
• Secondary:90 B 30

^*This research was supported by the National Science Council of the Republic of China.

^*This research was supported by the National Science Council of the Republic of China.

Notes

^*This research was supported by the National Science Council of the Republic of China.