Quality Improvement of Black Oxide Process in Casting

주조품 Black Oxide 공정의 품질개선에 관한 연구

In this paper, we consider the quality problem of black oxide process in casting for which Taguchi method is used. We explain simply the Taguchi method and existing problems in Black Oxide process. We analyze the problem by the quality improvement procedure proposed by Taguchi. The design factors and noises using cause-effect diagram are found, the experiment is made using orthogonal array. After ANOVA, the critical factors are determined and the optimal process condition is designed. After parameter design, we derive the tolerance levels. As a result of changing the levels of process parameters, the variance of quality characteristic was decreased by quarter and the average value was also decreased by half. We estimated the predictable profit of the improvement.