This research is focused on developing methods which increase the reliability and efficiency of Numerically Controlled (NC) machining. The award will be used to purchase a five axis machining center to experimentally test the concepts. The development of variational geometric models is an important topic of current research. The equipment purchased by this award will help the principal investigator's investigate how tolerance information contained within the geometric model of a mechanical part can be used to automate the selection of spindle speeds and feedrates in a NC milling operation. The tolerance information can be used to calculate the allowable cutting forces if the stiffness of both the workpiece and the machine tool is known. Geometric and mechanistic models of the cutting process will then be used to select appropriate speed/feed settings which result in actual cutting forces below the allowable threshold. Finally, force sensing during machining can be used to adapt to spindle speeds and feedrates to maintain acceptable tolerances and surfaces finishes. The practical realization of the stated goal requires two advances in the current state of the art: (1) an efficient geometric simulation method capable of verifying tolerance discrepancies, and (2) a reliable and complete model of the cutting process, capable of estimating cutting forces for a wide range of cutting conditions.
