A Study on the Warning Limit of Statistical Control Chart by the Heuristic Approach

Gang, Hyo-Sin

Journal of Korean Society for Quality Management > Volume 12(2); 1984 > Article

Journal of Korean Society for Quality Management 1984;12(2): 15-.

휴리스틱접근법(接近法)에 의한 관리도(管理圖)의 경고한계선(警告限界線)에 관한 연구(硏究)

강효신

이화여자대학교 대학원 경영학과

A Study on the Warning Limit of Statistical Control Chart by the Heuristic Approach

Hyo-Sin Gang

ABSTRACT

Since W.A. Shewhart (1931) developed the quality control method using the control chart, many theoretical and empirical works about such an analytical method have been done. However there are two major methods relating to the control chart analysis; the conventional 3 sigma control method and the warning limit method which has been suggested as a modification of the former. The conventional 3 sigma method requires to take a remedial action only when a quality characteristic is beyond the control limit (3 sigma). However, once a quality characteristic is over the control limit, searching and repairing an assignable cause requires time consuming job and high costs. Therefore if we set the warning limit between the central line and the control limit, we will be able to take remedial measures before too late. In spite of its advantage, much attention has not been paid to use the control chart with warning limit in Korean industries. The main object of this study is to examine improvement of quality and productivity when the control chart with warning limit is used.