Research On Highly Effective Fixed Abrasive Lapping Of Sapphire

With its good properties in mechanical, chemical, physical and other aspects, sapphire has beenwidely used in national defense, aerospace, scientific research, life and other fields. It has become theprimary problem of sapphire industrial development to obtain the processing technology of sapphirewith high material removal rate and good surface quality. Fixed-abrasive lapping technology has beenreceived more and more attention for its high efficiency, non-pollution, easy process-control and so on.In this paper, fixed-abrasive lapping technology was adopted to lap of the sapphire crystal. Theprocessing craft routes suitable for sapphire were designed and the process parameters of fixedabrasive rough lapping and precision lapping were optimized to enhance the machining efficiency andsurface quality. The main work and results are as follows:1）The processing craft of fixed-abrasive lapping technology suitable for sapphire was designed.The appropriate lapping time using different size abrasive particles were found; Then, the effect ofdifferent abrasive size on material removal rate, surface roughness and surface topography wasanalyzed; Finally, four process routes were designed. Considering the cost, efficiency and surfacequality, the route of W75rough lapping-W28precision lapping and the route of W75rough lapping–W14precision lapping are suitable for sapphire.2）The process parameters of fixed abrasive rough lapping and precision lapping of sapphirecrystal were optimized. The effect of workbench speed, pressure, the concentration of triethanolamineand abrasive pad types on material removal rate and surface roughness was investigated. And theoptimized process parameters for the high material removal rate and good surface quality wereobtained. The result shows that the optimal parameters are the patterned lapping pad, pressure0.1MPa, workbench speed120rpm and the concentration of triethanolamine5%. The material removalrate can reach31.1μm/min and the surface roughness is0.309μm. The effect of pressure, theconcentration of accelerator, type of lapping pad on material removal rate and surface roughness wasinvestigated, too. The result shows that the optimal parameters are pressure0.1MPa, theconcentration of accelerator10%, W28diamond FAP. The material removal rate can reach2.15μm/min and the surface roughness is0.139μm.3）The mechanism of fixed-abrasive lapping of sapphire crystal was investigated. The removalmodel of single particle suitable for sapphire was established, and the mathematical model of thetrajectory was established, too. Using single factor experiment, the distribution of trajectories and the effect of different parameters were observed: the larger the eccentricity is, the wider the range ofprocessing size will be. ω1and ω have no common factor, the trajectorie is most uniform, which ismost suitable for processing.