Control Chart Based on Middle Mean for Fine Manufacturing Process

Abstract

As the development of modern manufacturing industry, the products’ defects become fewer and fewer, especially in high reliability field, such as military, aerospace, and so on. But it’s not proper to eliminating the quality control of the process, because there may be some occasional factors that will result in some defects, and the product quality will be questionable. In other words, quality control for the fine manufacturing procedure is still very necessary. However, in such a situation, the traditional control chart is not suitable for use. A new method for quality control of near zero-defect process by using ZIP to model the fine manufacturing procedure is introduced in this paper, the situation when ZIP model can be adopted is analyzed, and an easy robust estimation of ZIP parameters by middle mean is proposed. Finally a case demonstrated in the paper will show how to use the method introduced in the paper.