MEASUREMENT OF TEMPERATURE ON DIAMOND-COATED TOOLS DURING MACHINING PROCESSES

A new measurement technique that can determine the absolute temperatur e at the rake face of diamond-coated inserts during dry turning is pre sented. The cutting temperatures measured by this infrared thermograph ic system vary depending on the workpiece material (AlZnMgCu 1.5, TiAl 6V4, GG25 alloys or green ceramics) and the cutting conditions. The me asured temperature distribution at the chip bottom immediately reaches a steady-state value (testing time is 0.1 s). It is possible to trans mit the temperatures measured to other machining operations, such as m illing and drilling. A strong relationship exists between the measured temperatures and the corresponding tool wear values. To verify the re producibity of calibration results, two methods are used to measure th e spectral directional emissivity of the chip bottom. The difficulties , problems and sources of error associated with the calibration method s are pointed out. This temperature measurement system can be used for determining the machinability of various workpiece materials with new cutting tools. In addition, it will help improve our understanding of tool wear mechanisms.