Integration of Milling Process Simulation with On-Line Monitoring and Control

This paper describes the practical integration of solid modelling with milling process simulation, on-line monitoring and supervisory control. Extensions to the ACIS solid modeller parse the NC program file, determine the tool/workpiece immersion geometry for each motion, and then subtract the tool swept volume to update the part shape. The immersion geometry is then used with a mechanistic milling process model to schedule optimal feedrates, to provide on-line reference data for monitoring, and to calculate departure paths so that, if unexpected events require it, the tool can be moved smoothly away from the workpiece. The additional information is embedded into the original NC program. This information is recognised by a supervisory control computer that monitors the process, and uses the information to react intelligently to tool wear, breakage, or chatter. Experimental results are presented to demonstrate the validity of the technique.