Material Removal Mechanisms Of Silicon Carbide Micro-milling Based On Indentation Characteristics

Silicon carbide has excellent physical properties,so it widely used as optical lens in optical equipment.And the inefficient processing method is the main problem that limits Si C further development.The research on the processing method and removal mechanism of silicon carbide will help to improve the processing efficiency of silicon carbide materials and obtain better processing quality.Therefore,important process variables and removal mechanism of silicon carbide micro-milling are researched.Then,the relationship between processing parameters and micro-milling quality of brittle materials can be obtained.It has important theoretical significance and practical application value.Firstly,micro-milling characteristics and the difference between micro-milling and traditional milling are analyzed.Based on this,instantaneous cutting thickness model of micro-milling silicon carbide with polycrystalline diamond tool is established.It is suitable for vertical milling and spindle tilt milling and represents the value of cutting thickness in three-dimensional space during milling,and considers the influence of the tool tip radius.The model is solved under different processing parameters,and get the trend with the processing parameters.Then,brittle materials crack initiation process under the indentation action is analyzed.Based on this,the relationship between the critical load of crack initiation and the crack size is established,and stress intensity factor is established.The instantaneous cutting thickness is introduced by the change of strain rate in micro-milling to establish dynamic fracture toughness.Material removal mechanism can be analyzed by joining it and stress intensity factor.Substitute instantaneous cutting thickness into ABAQUS finite element simulation to verify the accuracy of the model.The finite element simulation of indentation is also carried out,and the critical load during crack initiation is analyzed to verify the accuracy of the theoretical model.Finally,in order to further verify the theoretical results and the simulation results,the experimental study of silicon carbide micro-milling was carried out.The different processing parameters were tested separately,and the experimental surface quality and cutting force amplitude were analyzed to verify the correctness of the theory.