This research effort is focused on a computer system for automatic generation of feedrates for improving the efficiency of Computer Numerically Controlled (CNC) machining. Reliability is also improved by in-process adjustment of the feedrates to handle material property and cutter geometry changes. The goals are to be accomplished through: (1) integration of geometric and mechanistic end milling models for volume calculations and automatic selection of feedrate for milling sculptured surfaces; (2) in-process adjustment of the programmed feedrate by comparing the actual cutting force (power) to the predicted force (power). A program to automatically select the feedrates for complex sculptured end milling cuts is to be developed from experimentally verified mechanistic and geometric models of the end milling process. The program will be experimentally tested using Numerically Controlled (NC) programs supplied to the research team by an industrial partner. The programs are used for machining stamping dies for complex sculptured surfaces. The results in terms of cutting time, tolerances, and surface finish will be compared to industry results, where feeds and speeds are set manually. On-line adjustment capability of the programed feedrates will be added to the University of New Hampshire CNC machine to provide a method to adapt the feedrates to different workpiece materials and cutter wear. This project should lead to four advances in the state-of-the- art: (1) an improved mechanistic model of the end milling process; (2) integration of mechanistic and geometric models into one system; (3) method to calculate the necessary end milling cutting feedrates based on geometric tolerance information; (4) an experimentally proven on-line feedrate adjustment method.
