Journal of Manufacturing Processes Vol. 8/No. 1 2006 54 Performance-Based Predictive Models and Optimization Methods for Turning Operations and Applications: Part 1—Tool Wear/Tool Life in Turning with Coated Grooved Tools K.C. Ee, Peripheral Computer Support, Inc., Fremont, California, USA P.X. Li, Sumitomo Metal Mining USA, Inc., Oceandale, California, USA A.K. Balaji, University of Utah, Salt Lake City, Utah, USA I.S. Jawahir, University of Kentucky, Lexington, Kentucky, USA R. Stevenson, General Motors R&D Center, Warren, Michigan, USA Abstract Tool wear/tool life is an important aspect commonly con- sidered in evaluating the performance of a machining pro- cess. The advent of new grooved tools with complex chip-groove geometry has required a better understanding of their effects on tool wear/tool life. This paper presents an overview of research at the University of Kentucky on ex- tensions to the conventional tool wear and tool life method- ologies when machining with grooved tool inserts resulting from the more complex wear features observed and the more subtle failure criteria applied. The influence of cutting conditions including the cutting speed, feed and depth of cut on the tool life was studied experimentally using tools with chip-groove geometries and different tool coatings. It was shown that the slope and intercept of the log-log plot of tool life versus feed, for example, change considerably for different chip-groove geometries or different tool coatings. An empirical tool-life equation to consider the effects of these parameters was proposed. The approach described required that 11 tool wear/tool life tests be conducted for every tool insert. In a comparison between predicted and experimen- tal tests involving 200 production trials, this approach pre- dicted tool life within 24% of the results encountered, while tool-life estimations using conventional approaches yield- ed results that gave an error of more than 300%. Further- more, an ‘equivalent toolface (ET)’ model was developed to correlate progressive tool wear to changes in chip forma- tion with corresponding predictability of the dominant wear modes in turning with grooved cutting tools. Keywords: Predictive Modeling, Tool Wear, Tool Life, Coat- ings, Grooved Tools Introduction Tool wear/tool life estimates and the correspond- ing economic analysis are among the most impor- tant topics in process planning and machining optimization. It is commonly known that tool failure occurs due to accelerated wear or premature chip- ping, breaking, and thermal cracking (Cook 1973; Boothroyd and Knight 1989). When machining with flat-faced tools, either flank wear (VB) or crater wear (KT) are often considered as a measure for tool wear/ tool life (ISO 3685 1993; ASME 1985; Colding 1959; Rubenstein 1976; Usui, Shirakashi, and Kitagawa 1984), although other types of wear, such as groove and notch wear, may also be significant (Chandrasekaran and Johnsson 1994), and total tool Manufacturing Engineering Research Digest Series The Manufacturing Engineering Research Digest series aims to disseminate current research in a variety of manufacturing areas. The approach is to synthesize—or digest—manufacturing research to empower the practicing engineer toward innovative problem solving. The published papers are not intended to be historically and academically exhaustive reviews, but rather to present appropriate content that has potential industrial application. The papers meet rigorous academic review standards for content, citations, and relevance to manufacturing researchers as well as pass critical evaluation by practicing manufacturing engineers. For information on how to contribute to the Manufacturing Engineering Research Digest series, send an e-mail to publications@sme.org. Journal of Manufacturing Processes Vol. 8/No. 1 2006