The Dynamic Friction Dressing Of The Diamond Block

Carbide,ceramic,glass and other hard brittle materials have a series of excellent performance,such as,the high strength,high hardness,high wear resistance,corrosion resistance and heat resistance,widely used in machinery,electronics,communications,optics and other cutting-edge technology and defense.The fine abrasive diamond wheel is used to the precision grinding of hard and brittle materials,but there are some disadvantages in the process of processing,such as the severe wear,frequent dressing and uncontrollable surface accuracy.The coarse diamond wheel has the merit of large abrasive size,large chip accommodation space and high processing efficiency and controllable surface accuracy.In order to precisely grind hard and brittle materials by the coarse diamond wheel,dressing of wheel is very critical.But diamond has the property of abrasion resistance,it is extremely difficult to dressing of the wheel.In this paper,the dynamic friction dressing experiments of diamond abrasive brick were conducted with W-Mo-Cr alloy material.The main research contents and conclusions are as follows:(1)Based on the feature of the diamond abrasive surface morphology,we establish a finite element model for dynamic friction dressing diamond wheel.The temperature field of dynamic friction dressing diamond wheel was simulated with the help of ANSYS thermal analysis software.According to the temperature range of diamond graphitization to select the appropriate dressing process parameters,the dressing velocity range is 6000-9000 r/min and the dressing pressure range is 20-50 N.(2)Diamond wheel is dressed under different pressures and speeds.Through investigating the bearing capacity of abrasive,the surface morphology of wheel and the wear amount of dressing tool to develop optimal dressing parameters.The results show that the bearing capacity of abrasive is 7.013% under dressing parameters 3.18 MPa and 8.38 m/s,the surface morphology of wheel and the he wear amount of dressing tool are better controlled.(3)The abrasive height consistency and surface morphology of the diamond wheel are detected by laser confocal microscopy and scanning electron microscopy before and after dressing.During the dressing process,the wear forms of the abrasive grains are complete,wear flat,broken,fracture and there is no shedding,blocking phenomenon.The height difference of different abrasive reaches 60~100 ?m before dressing.The height difference of different abrasive is within 25 ?m after dressing.The improvement of the contours is conducive to improving the surface quality of the grinding wheel.(4)The surface roughness and surface morphology of WC material were compared before and after grinding.The surface quality of the WC material has been greatly improved and the surface roughness reaches 0.149 ?m.In the grinding process,with the increase in the speed and the reduction of the grinding depth,the surface quality of WC material is evidently improved.