Study On Cutting Mechanism Of Porous Diamond Abrasive Particles And Grinding Performance Of Grinding Wheel

Precision parts made of hard and brittle materials such as monocrystalline silicon,sapphire and single crystal silicon carbide have the characteristics of high mechanical strength,good chemical stability and low coefficient of thermal expansion.They have been widely used in communication,aviation,aerospace,national defense and other fields.Although the current ultra-precision grinding technology has been able to realize the high-quality machining of hard and brittle materials,it is difficult to realize the ductile removal of hard and brittle materials in the grinding process due to the existing ultra-precision grinding machine and grinding technology.There are many micro cutting edges on the surface of porous diamond particles,which is helpful to reduce the cutting force and cutting heat.At the same time,the surface of the porous diamond particle is rough,which further improves the bonding strenghth of the binder.Due to the reduction of impact strength,porous diamond can form a new cutting edge through its own micro crushing under low pressure,so as to achieve the effect of self-dressing.Therefore,taking 4H-SiC as the research object,this paper carries out the research on the cutting efficiency of porous diamond particles and the ultra precision grinding performance of porous diamond grinding wheel,so as to improve the performance of diamond grinding wheel and the processing quality of hard and brittle materials.The work of this paper includes:(1)The molecular dynamics method was used,the grinding models of conventional diamond abrasive and porous diamond abrasive were constructed respectively.The correct potential function and ensemble were selected,and the reasonable simulation parameters were set.The material removal mechanism of 4H-SiC was studied,the multi edge cutting mechanism of porous diamond was clarified.(2)The experiment of single abrasive particle scratching 4H-SiC was carried out.The scratch morphology,scratch length,width,depth and material removal volume were taken as the evaluation indexes to compare and analyze the effects of porous diamond abrasive particles with different corrosion degrees on 4H-SiC removal mode,damage type and scale.The results show that the removal form of 4H-SiC by conventional diamond abrasive particles is mainly brittle fracture,and the removal mode of 4H-SiC by porous diamond abrasive particles is both brittle fracture and ductile removal.(3)With the help of acoustic emission detection technology,the acoustic emission signal characteristics of wear particles in different wear stages in the scratch experiment were analyzed.The wear mechanism of porous diamond abrasive particles was studied based on the micro morphology of abrasive particles.(4)A porous diamond grinding wheel for 4H-SiC wafer thinning was developed.The grinding performance of the grinding wheel was analyzed by taking the machining surface morphology,surface roughness and material removal rate as evaluation indexes.The results show that using porous diamond grinding wheel to process 4H-SiC can obtain better surface quality and lower surface roughness.