Research And Development Of The New Dynamical Cutting Temperature Measuring System For Chemical Explosive Material

The project of the new dynamical cutting temperature measuring system for chemical explosive material is funded by China Academy of Engineering Physical (NO. 2001Z0301). The measuring system was checked and accepted by the users in July 2004. The high appraise was given for its excellent function.Hard particles distribute randomly inside chemical explosive material. When machining such kinds of material, high instantaneous workpiece temperature will occur. There will be much danger when the workpiece temperature exceeds a special value. So it's significant to test the instantaneous temperature quickly and accurately for war industry enterprises.The thin-film thermocouple is introduced to measure the cutting temperature dynamically in this paper. And the rule of cutting temperature is gained, which can be used to help enhance the machining efficiency by choosing the most optimized cutting conditions in war industry enterprises.A great effort has been concentrated on the following aspects: structure design of the temperature sensor, preparations of insulating thin-film (Microwave Electron Cyclotron Resonance Radiant Frequency Magnetron Sputtering is applied), preparations of alloy film (Multiple Arc Ion Plating is applied), static calibration, dynamical calibration, cold junction compensation and signal processing, simulated cutting experiment and on-the-spot cutting experiment, data analysis, error analysis of dynamical cutting temperature and so on. Preparations of insulating thin-film and alloy film are the key to the project and have been emphasized in this paper.Response time of the thin-film thermocouple is 0.8 millisecond so that it can measure the temperature of workpiece quickly. Furthermore, this newly developed thin-film thermocouple has high sensitivity and good linearity. The sensitivity is 20.9 microvolt per centigrade. And the nonlinearity error is less than 0.32% among the range of 0~600℃. The relative error of the whole temperature measuring system is 1.19%. The result of cutting experiments show that the cutting speed and the depth of cut are the main factors that affect the cutting temperature when machining the chemical explosive material, while the feed rate has little contribution to the rise of temperature.