Statistical Process Quality Control Based On Gray Model And Bayes Theorem

Quality is the key for one enterprise standing in the society, which is the basis of its development. The traditional quality control mainly rely on the workers’ inspection it’s past-action control, in this way it can cause much waste. SPC is one technology which uses the statistical approach, and offset the deficiency in the traditional quality control. In multi-varieties and small batch, the traditional SPC has the same malpractice, and the quality control methods of most enterprises lack timeliness. And it can’t achieve the goal of survival and development of one enterprise. Using the traditional quality control method will lead to the rate increasing of unaccepted production, adding cost, wasting resources,and will have hindered enterprise’s process.Firstly, according to the characteristic of multi-varieties and small batch, combining the theory of grey prediction with the Bayes theory, establishing the quality control chart of Bayes. Applying Matlab simulate the random data to verify the control chart is effective in multi-varieties and small batch. Secondly, using Matlab to simulate average run length of Bayes chart and EWMA chart, compared Bayes chart with EWMA chart, verifying the Bayes chart is more suitable for the manufacture process of multi-varieties and small batch.Analyzing the characteristic of multi-varieties and small batch, using the grey model to forecast and enlarge the data to verify this method is suitable. By comparing, in the same situation, Bayes’ feedback speed is faster than EWMA. Finally, it is aimed at the problem of quality and control manufacturing automobile parts company steering wheel.Established control model of manufacturing. Analyzing and calculating the collected data by Matlab. Verified this model is effective.This paper regards the method of SPC in multi-varieties and small batch as entry point, regarding the theory of SPC and process capability. By studying the process capability of multi-varieties and small batch by principle of statistics, comparison method,mathematical derivation, we can establish the application of framework, complete method system of quality forecast and control. This method has important theoretical and practical signification to improve the quality of products.