Effect Of Abrasive Sizes On Processing Performance Of Fixed Aggregate Diamond Abrasive Pad

Fixed abrasive machining technology is the main means of precision and ultra-precision optical materials processing.Hydrophilic fixed abrasive lapping and polishing pad(FAP)is the research focus at this stage.Abrasive are one of the key factors in whether a hydrophilic FAP can self-conditioning.FAP surface will be "glazed" phenomenon,the material removal rate will decrease,the stability of processing efficiency and the surface quality of the workpiece will be affected with the pad wear time increases in the traditional hydrophilic FAP lapping processing.In this paper,diamond aggregate grains with the advantages of self-sharpening,utilization ratio and good surface quality were applied to hydrophilic FAP to explore effects of aggregate abrasive on lapping performance of fixed abrasive Pad.The main research work and results were as follows:(1)Preparation route of the specified particle size diamond aggregate abrasive was obtained by the water classification technical parameters were determined according to the vertical wet classification principle.Results show that the shape of the aggregate abrasive by pressureless sintering was full and rounded with ellipsoid shape.The classification accuracy of powder was fine under the premise of laminar flow and particle free-settling.(2)The effects of abrasive properties(single diamond,aggregate diamond)and aggregate particle size on the lapping performances of fixed abrasive pad were explored by single-factor experiment.Results show that the fixed diamond aggregate abrasive pad had good lapping stability,which can optimize both material removal rate and surface roughness.The material removal rate was the highest when the secondary particle size of aggregated diamond was 15~20 μm.(3)The effects of primary particle size,secondary particle size,applied load,slurry flow rate on the lapping performances of fixed aggregate abrasive pad was explored by the orthogonal experiment.Results show that the comprehensive choice of the original particle size and secondary particle size of the aggregated diamond had the most significant influences on the lapping performances of the fixed abrasive pad.The optimal lapping process of quartz glass when the original particle size and secondary particle size were 1~2 μm and 20~25 μm respectively,applied load 14 kPa and slurry flow rate 60 ml/min.(4)The machining model of hydrophilic fixed aggregate abrasive pad was proposed.The microscopic contact model of the fixed aggregate abrasive pad was analyzed,and the material removal mechanism of aggregate abrasive FAP was discussed.Establishing models of the number of effective abrasives,cutting depth and material removal rate.The results show that diamond aggregate grains can guarantee a higher and more stable material removal rate,for which have good self-sharpening.