Research On Microwave Sintered Vitrified Bond Diamond Grinding Wheel

In this paper,vitrified bond diamond grinding wheel materials with good mechanical properties by microwave sintering were fabricated by determining the distribution ratio of vitrified bond diamond grinding wheel materials groups,microwave sintering electromagnetic field simulation analysis and improving microwave sintering process parameters.The mechanical properties and microstructure were studied.At the same time,a test bench for surface grinding was designed.The effects of different radial pressure,grinding speed and grinding time on the grinding ratio of diamond grinding wheel segments,surface roughness and morphology of silicon wafer were studied.The wear mechanism of diamond wheel segments is analyzed.When the sample is at the height of 150 mm in the sintering chamber,the electromagnetic field distribution of the three sections passing through the center of the sample is the most uniform,and the electromagnetic field strength gradient is small,which is favorable for uniform heating and sintering of the best vitrified bond diamond grinding wheel.The diamond grinding wheel blocks which were sintered at 800?for 30 minutes had optimal mechanical properties.Its Rockwell hardness and bending strength were 62.9HRB and 50 MPa,respectively.The SEM pictures show the wetting and wrapping of the diamond abrasive grains by the vitrified bond were best,and the number and size of the pores are appropriate.The effect of surface grinding process on the surface roughness of silicon wafer and the grinding ratio of grinding wheel segments were studied.The results show that the surface roughness value decreases with the increase of the radial pressure,decreases first and then increases with the increase of the grinding speed,and decreases with the increase of the grinding time,the surface roughness value was the smallest at 22 N and 200r/min for 60 minutes,which can reach 0.41?m.The grinding ratio gradually decreases with the increase of the radial pressure,and increases first and then decreases with the increase of the grinding speed,and decreases first and then stabilizes with the increase of the grinding time.The maximum value can be up to 1.6 and the minimum value is 0.17.The brittle fracture caused by the extrusion of diamond abrasive grains on the surface of the silicon wafer and ductile grinding are the main reasons for the formation of the surface morphology of the silicon wafer.The surface topography change trend of the silicon wafer is consistent with the change trend of the surface roughness value.The wear mechanism of the diamond wheel is mainly whole shedding and broken small pieces fall off of diamond abrasive.