Effect of Al₂O₃ hollow sphere on properties of resin bond diamond disc in sapphire grinding

To improve the lapping effect of sapphire grinding, Al₂O₃ hollow sphere is added into resin bond diamond grinding disc.Effect of sphere size and volume fraction on strength of the bond and performance of the disc are studied through mechanical test, SEM analysis and actual grinding.Resultsshow that as the size and proportion of sphere increase, the bending strength of the sample decreases, and that when the volume fraction of sphere reaches 30%, sphere size has no obvious effect on the strength.It is also found that efficiency of grinding sapphire is increased through adding Al₂O₃ hollow sphere, and the surface roughness of sapphire is improved.In conclusion, when volume fraction of sphere is 20%, the grinding disc has best comprehensive grinding performance, whose R_a decreases to 0.249μm and the efficiency is increased by 82.6% compared with that of non-sphere grinding discs.