Effective use of coated tools — the wear-map approach

One primary motivation to use coated tool inserts instead of uncoated ones is their much-improved resistance to wear during machining, resulting in an increase in tool life. A whole host of techniques has already been developed to deposit different types of coatings onto different types of inserts. These have yielded coated inserts with a variety of performance characteristics at a range of costs. In this paper, a summary is first presented of work carried out with the aim of understanding the global wear characteristics of cutting tools; the tools used in the investigations ranged from uncoated high-speed-steel and carbide tools to selected coated inserts. From these studies, it was found that machining conditions (feed rate and cutting speed) played a critical role in determining the extent of wear on these cutting tools, whether or not they were coated. It was also found that the extent of tool wear and its relationship to the machining conditions could be readily appreciated through specially constructed wear maps. It is suggested that coated inserts could be employed in a more cost-effective manner when the machining conditions are determined based on the wear maps developed for these tools.