MEASUREMENT OF 3-D TOOL WEAR BASED ON FOCUS ERROR AND MICRO-COORDINATE MEASURING SYSTEM

This paper presents a technique for measuring micromachining cutting tool dimensions. The technique uses machine vision and a geometric modeling platform (CAD software) as the means of constructing the 3-D shape of a cutting tool and obtaining the 3-D metrological data. In the technique, a sequence of images is obtained by continuously varying the distance between the cutting tool surface and the image detector. The focus information from the obtained images provides the 3-D shape of the cutting tool. In addition 3-D metrological measurement is conducted by a micro-coordinate measuring system. In the system, the 3-D shape of the cutting tool is converted into the form of IGES file. The IGES file is read by the geometric modeling platform (IDEAS). The available tools in the geometric modeling platform can be used as the coordinate measuring means. In particular, pointing tool can be used as a "virtual touch probe". The system provides the capability of measuring linear and angular quantities, establishing datum lines and planes from the imported shape of the cutting tool. The capability can be useful for measuring tool wear. Experimental results are presented and discussed to demonstrate the technique