Research on control scheme of coordinate data based on multivariate statistical process control

Coordinate measuring instruments are used broadly in quality monitoring of automatic manufacturing, which usually generate three dimensional coordinate data or vector data. That traditional SPC focused on scalar data monitoring causing a great loss of data information and increasing the second error probability of statistical process control easily. Thus it becomes more important to monitor coordinate data rather than scalar data like length etc. in order to implement dimensional control. In other words, coordinate data monitoring is an effective way to control dimensions of rigid parts. In this paper the coordinate monitoring method in manufacturing process is proposed. Multivariate statistical process control are used to bulid the monitoring scheme and the details of monitoring three basic geometrical elements, point, line and plane, are discussed. Performance of traditional statistical process control and the new proposed control scheme are compared. A numerical example of vector dimension data is put forward. Research results show the second type of error probability of the presented control chart is smaller and it has more operating validity than the traditional control charts.