Study On Temperature Field Of Single Crystal Germanium Micromachining

As an important infrared optical material,single crystal germanium is widely used in infrared temperature measurement,communication,bioengineering and aerospace.During the micro-cutting process of a single crystal germanium,changes in cutting temperature can lead to significant wear of the tool and thermal deformation in the cutting area,thereby reducing the quality of the processed surface of the material and the accuracy of the product.Cutting temperature has become an important factor affecting product quality,and there is a lack of in-depth researched on the distribution of micro-cutting temperature of single crystal germanium.Therefore,this paper explores the temperature field distribution law of single crystal germanium in the fine cutting process from three aspects: theoretical analysis,finite element simulation and single point diamond cutting test,in order to provide a certain theoretical data reference for the actual production.Firstly,the geometric cutting model is established by reference to the actual cutting process,and by using the thermal source method,the theoretical temperature-rise calculation model under the action of shear surfaces to heat source and the theoretical temperature-rise calculation models on the action of the friction heat source of the cutter and front knife surface is derived from the solution of the thermal conduction control equation.Secondly,the temperature distribution and the variation law of the single crystal radon under different cutting parameters(spindle speed,feed speed,cutting depth)and different tool parameters(front,back,tip arc radius)are analyzed through the simulation of finite element cutting.The simulation results show that the highest point of cutting temperature appears on the front knife surface and is closer to the cutting edge,the distribution of temperature in the cutting process is concentric at the highest temperature point of the tool front,the closer the maximum temperature point,the smaller the temperature change gradient;The temperature increases the fastest with the increase of the feed speed,the tool parameters have different effects on the temperature,the higher the negative front angle of the tool,the higher the temperature of the rear angle increases,and the temperature of the sharp arc increases slowly.Through MATLAB software,the theoretical temperature extremes under different cutting parameters and different tool parameters are calculated,and the relative error of the two with the finite element simulation result is within 10%,which confirms the accuracy of the theoretical model.Finally,the simulation results are verified by using a single point diamond cutting test to measure the cutting temperature with an infrared thermal imaging cameras and the surface roughness by means of an optical profiler.Through the analysis of the test results,the feed speed has the greatest influence on the cutting temperature and surface roughness,that is,the test results are most sensitive to the feed speed,and the higher the cutting temperature,the greater the surface roughness value.