Statistical Process Control and Stability Technology Processing Cylindrical Parts

Abstract

This paper presents a calculation algorithm for verifying on-line the stability of manufacturing process in large and mass series of some cylindrical parts the axes type. Through experimental researches, it was conducted a statistical control on a lot of sample parts to can determine the accuracy of machining on automatic lathes and grinding machines round. In the first phase, we performed a statistical analysis of the technological process preceding the manufacture of cylindrical parts in large and mass series. Checking the normality assumption of the deviations of parts machined, were could be established the main statistical parameters: arithmetic mean and standard deviation. With these parameters, we calculated the fraction of defective parts likely. In the second phase, we determined control limits for the arithmetic mean and standard deviation. With these parameters we pursued chronologically, development of effective size to the work piece. In this way, it can check on-line the stability of the technological process for well defined periods of time, between two successive adjustments of the machine tools.