ON THE VOLUMETRIC ASSESSMENT OF TOOL WEAR IN MACHINING INSERTS WITH COMPLEX GEOMETRIES: NEED, METHODOLOGY & VALIDATION

The objective of this paper is to qualitatively assess the inadequacies of the current manner of tool wear quantification and consequently to suggest/develop a more comprehensive approach to machining tool wear characterization. Traditional parameters used for tool wear representation such as flank and crater wear are no longer self-sufficient to satisfactorily represent the wear of the complex geometric profiles of more recent cutting tools. These complexities in tool geometries are all the more pronounced when catering to difficult-to-machine materials such as titanium and its alloys. Hence, alternatives to traditional tool wear assessment parameters are briefly explored and a suitable one is selected, that will help understand the very nature of the evolving wear profile itself from a three dimensional standpoint. The assessment methodology is further developed and standardized and suggestions for future use and development provided. The measurement system is evaluated using a gauge repeatability and reproducibility (R&R) study as well. The method is deployed for assessing tool wear during the machining of Ti-6Al-4V at selected process conditions for validation purposes. Further, concepts such as the M-ratio and its derivatives are developed to quantify the efficiency of the cutting tool during each pass as a function of time at a theoretically constant material removal rate (MRR).