Quality Control Chart And Its Software Implementation

Statistical Process Control can effectively control the rate of waster in the product process. In the paper, several questions about quality control have been discussed.Firstly, the basic concept and theory of the statistics process control are told about, and the two kinds of error, process capability index, decision rules and the average run length are proposed. How to use the process capability indices to analyze is introduced in detail. Then use many figure to explain each abnormity count the probability of every decision rules. Afterward, it shows that the relation with two kinds of error.In the third chapter, many control charts are introduced, such as Shewhart, dynamic cumulation sum, exponentially weighted moving average control chart, especial the dynamic CUSUM variance chart. The Markov chain method is used to calculate the average time to signal, in order to compare the fixed sampling interval control charts with the variable sampling interval. It sees that the unfixed sampling interval has shorter signal time. Then the EWMA variance chart is proposed.In the forth chapter, the development of SPC software is showed, which have three main parts, the requirement analyze, oral design, detail design. The software of Delphi 7 and Oracle are used to design the interface of the quality control chart, code and database. The most important code is given.