A New Approach to Spatial Tool Wear Analysis and Monitoring

The tool wear of cutting tools has a very strong impact on product quality as well as on the efficiency of machining processes overall. Despite the current high automation level in the machining industry, a few key issues prevent complete automation of the entire turning process. One of these issues is tool wear, which is usually measured off the machine tool and is still done by hand under a toolmaker’s microscope. There is no any industry wide procedure for automating the process of measuring wear. Furthermore, such conventional wear measurement requires stopping the automated turning, removing the tool, measuring the tool and putting the tool back to the holder, which is a considerable time loss relative to the tool’s life. Therefore, the in-line characterization of cutting tool wear is crucial for cutting cycle times and costs, as well increasing the overall efficiency of the machining process. This paper presents an innovative, robust and reliable direct measuring procedure for measuring spatial cutting tool wear in-line using a laser profile sensor. This technique allows 3D wear profiles to be determined, which is an advantage over the currently used 2D subjective techniques (microscopes, etc.). The use of the proposed measurement system removes the need for manual inspection and minimizes the time used for wear measurement. A tool life characterization is also performed. Based on this, a new tool life criterion is proposed that includes the spatial characteristics of the measured tool wear. In the next three subsections, extensive state reviews are performed.