Study On Deep Hole Grinding Technology Of Ultra-high Strength Steel With Large Deep Diameter Ratio

Ultra-high strength steel has excellent properties of high strength,high hardness and low thermal conductivity.It is widely used in aerospace and other fields to produce cylindrical parts with large aspect ratio,which have complex cavity,small aperture,thin wall and other processing characteristics.In order to meet the needs of the processing and production of cylinder parts with large aspect ratio in aeronautical industry,the problems of poor surface quality consistency,difficult control of material grinding removal rate,low processing efficiency and serious wear of grinding wheels exist in deep-hole grinding process.By analyzing the material properties of workpieces,deep-hole grinding wheels are selected and dressing schemes are determined,from grinding wheel dressing,grinding and grinding.In order to improve the material removal rate,surface processing quality,grinding wheel durability and processing effect of workpiece,CNC deep-hole grinding technology was experimented and explored from the perspectives of tool number,path planning and grinding scheme.The rough and fine grinding process parameters and the optimal grinding wheel dressing time of inner-hole grinding were determined,and the grinding effects of different end grinding schemes were compared and analyzed.The NC deep hole grinding process of cylinder parts with large aspect ratio was validated,which provided theoretical support for solving practical engineering problems of enterprises.It mainly includes the following contents:(1)By analyzing the shape,structure,chemical composition and physical and mechanical properties of the workpiece,the characteristic parameters of the grinding wheel are studied,and the deep hole grinding wheel is selected.(2)Based on deep-hole grinding experiments,the effects of dressing parameters and grinding parameters on material removal rate were studied,and a theoretical model of material removal rate was established.In order to obtain higher material removal rate of workpiece,dressing depth should be greater than 0.2 mm and Z-axis feed rate should be 300 mm/min in grinding process.The grinding depth should be greater than 0.20 mm and the Zaxis feed speed should be 180 mm/min.(3)Based on deep-hole grinding experiments,the effects of dressing and grinding parameters on the surface quality of materials were studied.In order to obtain a lower surface roughness value,the dressing depth should be 0.10 mm to 0.20 mm,the Z-axis feed speed should be 100 mm/min to 200 mm/min,and the grinding depth should be greater than 0.16 mm and the Z-axis feed speed should be 150 mm/min to 350 mm/min.(4)Based on deep-hole grinding experiments,the influence of Z-axis feed speed on grinding wheel grinding ratio is studied.When Z-axis feed speed is 180 mm/min,grinding ratio reaches 63.24,which can improve grinding wheel utilization rate and reduce wheel wear.The relationship between grinding wheel running times and material removal depth is studied to improve the grinding efficiency of deep and long holes,and the grinding wheel after dressing can complete five times of grinding wheel grinding.The grinding effect of different end grinding schemes is studied.The experiment shows that grinding scheme 2 can improve grinding condition,grinding efficiency and grinding ratio.(5)Grinding process verification of cylindrical parts with large aspect ratio was carried out,including the verification of processing methods and process parameters.The dimension accuracy and surface roughness of the workpiece were qualified,and the working time was reduced by 60%.