Application Research of Process Capability Analysis in Manufacturing Quality Control

Abstract

Process capability analysis are widely used in industry to achieve and maintain a high-quality level of manufactured items. Various indices have been proposed, but the most widely used are Cp, Cpk, Cpm and Cpmk. This paper gives the calculation method of the process capability index, discusses the process capability analysis and evaluation method, and analyzes in detail the process countermeasures of the process capability index is too large or too small. Through examples, the normality test method and controlled state test method for sample data are given. That is, the Q–Q probability plot and the Anderson–Daling test method are used to determine whether the sample sequence is normal distribution. The Xbar-R control chart is used to determine whether the sample sequence is in a process-controlled state. Using Minitab software, control charts and process capability diagrams were plotted, and process capability indices Cp and Cpk are calculated and analyzed. Finally, according to the quality data of customer feedback, the process capability level and state of the processing process are determined, so that the process capability can meet the customer’s requirements.