Manufacturing process control

摘要

A process control is provided for continuously monitoring and adjusting an apparatus for manufacturing discrete workpieces. The system measures a current workpiece by taking fifteen readings and deleting the highest five and lowest five readings and averaging the center five readings. This value is then used for sorting the workpiece in accordance with preset tolerance limits. The measured average value is also compared with an expected value which the system has computed and stored. An adjustment value is then calculated based on a comparison of the measured dimension of the current workpiece and a measured dimension of the last-produced workpiece and the expected value for the current workpiece. The apparatus is then adjusted in accordance with the computed adjustment value. The system also has the ability to calculate the statistical distribution of a plurality of previously produced workpieces and to adjust the apparatus in accordance with a comparison of the dimension of the current workpiece with the three sigma limits of the distribution. Furthermore, the system has the capability of calculating a statistical distribution and printing out this data as well as performing a capability study.