A Model-Based Monitoring and Fault Diagnosis Methodology for Free-Form Surface Machining Process

Abstract

In this paper, a process model-based approach has been proposed for monitoring and fault diagnosis in the multi-axis ball end milling process. Besides its ability to deal with complex cutting geometry in free-form surface machining, the method has the capability of not only detecting the presence but also estimating the magnitudes of faults, which include flute chipping, breakage and spindle/cutter axes runout. A threshold-based fault detection method is developed based on the analysis of harmonic power distribution in the cutting force signal. A genetic algorithm approach is used to search and determine the fault pattern and magnitudes. The new approach is validated through both constant cross-section cut and free-form surface machining tests on 1018 steel.