Research On Micro-grinding Process And Micro-damage Of Silicon Carbide

In recent years,as a third-generation semiconductor material,silicon carbide material has been developed and used rapidly and widely due to its moderate density,good thermal shock resistance,strong radiation resistance and a series of excellent physical properties and good chemical stability.Silicon carbide is a hard and brittle material.Ordinary turning,milling and other processing methods are not only easy to cause tool wear,but also cause serious damage to the surface of the workpiece.Micro-grinding processing methods can not only meet the needs of silicon carbide as optical components.It has application conditions such as smooth surface,high shape accuracy and good surface integrity.Compared with polishing,micro-grinding processing can also improve processing efficiency greatly.This subject has formulated the overall plan for the research of silicon carbide micro-grinding process and micro-damage.Through the micro-grinding of single-crystal silicon carbide materials,the effects of grinding parameters on the surface roughness and surface profile of silicon carbide,the generation and suppression of grinding chatter marks,and the sub-surface micro-damage are studied.Firstly,the experiment of micro-grinding roughness of silicon carbide is carried out.Using a comprehensive experimental method,a preliminary exploration is made on the optimal level of the three factors of grinding wheel speed,feed speed and grinding depth.Two orthogonal experiments are carried out on the basis of the better level parameters obtained in the comprehensive experiment to find the best level parameter combination within the range of the experimental parameters.Secondly,the orthogonal experiment method is used to study the aspheric surface deviation of silicon carbide micro-grinding.The experiment obtains the influence law of each grinding parameter on the deviation,and optimizes the aspheric surface deviation through the compensation processing experiment.Research shows that using a grinding wheel with a particle size of 1200#,the minimum roughness Sa obtained in the overall experiment is 15.101nm,and the minimum roughness Sa obtained after two orthogonal experiments is 2.533nm The lowest surface deviation Pt value obtained by the aspheric orthogonal experiment was 7.485?m.On this basis,after two compensation processing experiments,the surface deviation Pt value dropped to 3.088?m.Then,an experimental study was carried out on the chatter marks on the surface of silicon carbide during micro-grinding.Analyze the causes of chatter marks and formulate corresponding measures to suppress chatter marks.The experimental results show that:within a certain range of experimental parameters,the greater the speed ratio of the grinding wheel to the workpiece,the less obvious the chatter marks.Use a diamond pen to dress the grinding wheel,and the effect of suppressing chatter marks is better than that of green silicon carbide stone dressing.Adjust the dynamic balance of the fixture and the silicon carbide workpiece.The lower the PV value of the adjusted dynamic balance,the less obvious the vibration pattern.Finally,the research on the subsurface damage of silicon carbide is carried out.The cross-sectional microscopy method was used to study the maximum crack depth of the sub-surface under different grinding parameters.The experimental results show that within a certain parameter range,the increase of the grinding wheel speed,the decrease of the feed rate and the decrease of the grinding depth are all conducive to reducing the sub-surface damage of silicon carbide micro-grinding.Through orthogonal experiments,the optimal horizontal parameter combination for the maximum crack depth within the parameter range of this experiment is determined,and the maximum crack depth under this horizontal parameter combination is 9.636 ?m.