Preparation And Micro Grinding Performance Of Spherical PCD Micro Grinding Head With Textured Surface

With the continuous development of advanced technology in microelectronics industry,national defense engineering and biological engineering,the demand for hard and brittle micro-freeform surface parts is increasing day by day,and the demand for surface quality,size and shape precision is increasing.Due to the physical characteristics of high hardness and high strength of hard and brittle materials,it is inevitable to have the problems of low surface quality caused by serious brittle fracture and serious edge collapse in the processing area in the processing process.Micro grinding heads prepared by CVD and other methods can often obtain better surface quality of hard and brittle materials.However,due to the short life of the micro grinding heads and the simple structure and shape of the existing micro grinding heads,they can not adapt to the efficient processing and removal of special materials.In view of this,a surface textured spherical PCD micro grinding head is proposed in this paper.Through structural design and simulation analysis,four kinds of spherical PCD micro grinding heads with different surface textures are prepared by combining two special machining technologies of micro EDM and laser ablation machining.By comparing the micro grinding performance of different surface texture micro grinding heads,the optimal parameters for machining quartz glass are discussed.The specific work of this paper is as follows:(1)According to the design idea of improving the flow channel of grinding fluid and increasing the chip holding capacity of cutting tools,the structures of four kinds of surface textured spherical PCD micro grinding heads was designed: non texture,straight texture,cross texture and spiral texture;According to the characteristics of PCD material,the radial deviation of micro grinding head under load was analyzed;The finite element analysis software ANSYS was used to carry out statics analysis of spherical PCD micro grinding heads with four kinds of textures,and the law between the maximum stress and maximum deformation caused by the distance between the clamping position of the micro grinding rod and the micro grinding head and the load on the micro grinding head was investigated.(2)Using micro EDM technology,the effects of average current and pulse width on material removal were studied;The spherical PCD micro grinding head prepared by micro EDM was ablated by nanosecond laser.The effects of laser power and laser scanning times on the ablated surface morphology of PCD were qualitatively explored.Finally,spherical PCD micro grinding heads with four textures were prepared by using the optimized micro EDM and laser ablation parameters.(3)Taking the micro groove edge damage and surface roughness Ra as evaluation indexes,the micro grinding performance differences of spherical PCD micro grinding heads with different textures were explored.The experimental results showed that the surface textured spherical PCD micro grinding head can effectively reduce the drag of debris and the occurrence of central zero velocity in micro grinding.Spiral textured spherical PCD micro grinding head could grind on the surface of quartz glass to form arc surface with good quality.The spiral textured spherical PCD micro grinding head was selected,the orthogonal experimental method was adopted,and the workpiece surface roughness and material removal rate were used as evaluation indexes to optimize three process parameters,such as spindle feed speed,spindle speed and grinding depth.Among them,the spindle feed speed was the key factor affecting the material removal rate,and the change of any of the three parameters of grinding depth,spindle speed and spindle feed speed would have a significant impact on the surface roughness of the workpiece.The results showed that the micro grinding quality of the surface textured spherical PCD micro grinding head proposed in this paper was better because it had surface texture,and the spiral texture was the best among the four surface textures.This study had certain reference significance and value for the structural design and preparation of PCD micro grinding head.