Study On Wear Mechanism Of Brazed Diamond Grinding Wheel During SiC Grinding And Its Effect On The Ground Quality

Silicon carbide(SiC)ceramics,due to superior physical and chemical properties such as high specific stiffness,high-temperature resistance and corrosion resistance,have been applied in optical reflectors,nuclear installation,and astronautics.Diamond grinding wheel,which is widely utilized in SiC grinding,is the key to enable high precision and efficiency machining.However,as a typical hard and brittle material with high strength and low fracture toughness,SiC is very difficult to machine,and could lead to severe diamond grinding wheel wear.Caused by wheel wear,brittle regime machining results in high conversion cost and bad machined surface quality.Thus,in the present research,a wear experiment of single-grain grinding of SiC was conducted to investigate the wear process and mechanism of diamond grain.Besides,a diamond wheel grinding experiment was implemented,where the wear state of diamond grinding wheel was analyzed to clarify the influence of grinding wheel wear on the final surface quality of SiC.The main work and conclusions are as follows:(1)By conducting the simulation and experiment of single-grain grinding of SiC,it is found that the wear process of diamond grain has,in turn,experienced platform wear stage,microcrack stage and pull-out stage.Before the cutting edge broken,the development of grain wear is very slow,while after that,the wear rate will increase first rapidly then steadily.The further experiment results illustrate that the critical undeformed chip thickness(0.3?m)could have the largest platform wear area,the largest grinding force while the shortest life.(2)According to the results of single-grain experiment and simulation,a new definition of wear state in monolayer brazed diamond grinding wheel is proposed.As the development of wear state counting system based on convolutional neural network,the wear state of grinding wheel can be easily measured during the experiment.(3)The wear state counting system was applied in the wear experiment of diamond wheel grinding of SiC.According to the study of SiC surface quality,surface morphology and brittle-ductile ratio,the wear process of grinding wheel should be concluded as two stages,where the first stage exerts positive influence on machined surface quality.The experiment also shows that the massive failings of active grains is attributed to the decrease of grinding force and the improvement of SiC surface quality.