Reducing scrap due to missed operations and machining defects in 90PS pistons

Rejection analysis deals with the inspection of the quality of products and efficiency of the plant which are very important in the manufacturing process. It offers practical solutions to problems that arise during the piston manufacturing process. In this paper, a hybrid decision-making and quality control technique was applied to minimize the rejection rate of 90PS pistons. An observational technique was used to achieve the particular target involves the nature of the defect, a check sheet to gather data on the number of defects that occurred over the past three months, a Pareto chart was used to identify the main defect percentage, and a cause-and-effect diagram was used to find the causes. Results show that various defects were mitigated. As a result, the operation missing scrap in the manufacturing line was reduced from 1.52 to 0.50%, skirt size scrap from 0.64 to 0.20%, transportation scrap from 1.50 to 0.50%, and pinhole/compression height scrap from 2.33 to 1.00%. The results of this study helped improve the efficiency of the plant by minimizing the cost.