earticle

영어

The goal of the proposed research in this dissertation is to develop the control chart that considers the advantage of effeciency in control chart and short-coming of difficulty in detecting the small shift, at the same time. This research, therefore, develops new VSI synthetic control chart that considers convenience of use in the field, and perception of change of process applying VSI techniques to synthetic control chart, simultaneously. Proposed control chart, also, can accomplish high quality as well as low cost by designing optimal economic parameter of control chart. The results in this study are summarized as follows ;First, in case of process mean shift δ = 1.0σ, when economic optimal parameter of VSI X-CRL synthetic control chart is at L=5, n=4, the expense amount is the least. The control parameters of CRL/S control chart are determined as k=2.239, k'=0.974, d1=0.100, d2=1.397. Proposed control chart brings cost-cutting effect of 3.04% control expense less than FSI control chart. Second, control cost shows a tendency to increase gradually as increasing λ, parameter of exponential distribution. There is no effect in control limit effect of each control chart by increasing λ, but sampling interval, d1 and d2, goes shortly to reduce time to find special causes. Proposed VSI X-CRL synthetic control chart in this research can use more easily than traditional control chart along with applying run rule and the performance is superior to traditional control chart. It may not be difficult to establish the optimal economic control parameters to apply the practical cost parameters in field.