The analysis and study of process capability plots

Process capability indices (PCIs) have been widely used in manufacturing industry, but it is not reliable and cannot give more information about the process detailed to use them in traditional way. A method to solve the problem is ldquoprocess capability plotsrdquo, which can provide us information about the location and the spread of the studied characteristics and the process simultaneously. It is a powerful tool to monitor and improve the capability of industrial processes, and it should be given more attentions to for quality engineering practitioners and theorists, especially in China, where is rarely research about it. With the development of the method, four types of ldquoprocess capability plotsrdquo are introduced here, users should choose suitable type of graphic method-ldquoprocess capability plotsrdquo according to the actual situation of the process.