In-Process Optical Gauging for Numerical Machine Tool Control
This chapter deals with the investigation of a remote, non contact optical gauging system required for an in-process measurement by the machine control. The random surface grain of actual machined surfaces causes severe distortion of the measurement process. One common feature of all machining applications, where the dimensions of a workpiece are continually changed in process, is that measurement at the point of material removal is possible, and consequently there is some inevitable delay between the cutting operation, the measurement of the resulting dimension. Machining of contours requires considerably more data processing, a more powerful computational system may be required, although an existing system may have enough reserve capacity. The chapter also deals with the study of loop closure by monitoring, using a laser optical technique, the dimension of the actual work-piece as close as possible to the point of contact of the cutting tool so that all errors due to the machine and tool are within the control loop.