Research On Fixed Abrasive Elastic Machining For Optical Components

At present,precision optical components have been widely used in the field of military project and civil photoelectric.The current manufacturing process of precision optical components usually adopts "precision grinding + deterministic polishing".However,Grinding has an advantage of high removal efficiency,but leaving lots of surface damage in the workpiece after processing.On the contrary,optical component is substantially no subsurface defects after polishing.Nonetheless,polishing removal efficiency is extremely low.Usually,polishing tool take loose abrasive and pitch pads,which have two insufficiencies for high-accuracy and high-speed fabrication.On the one hand,the stability of removal functions could not be guaranteed for the instability status of loose abrasive's concentration and the attrition of pitch pads.In addition,due to the dissociative status of abrasive,they could not provide a higher shear force to remove material,which result in low removal efficiency of polishing.It is urgent need of tool in current,which have lager removal efficiency,and less surface defects and subsurface damages.Compared with loose abrasive,fixed abrasive polishing brings in many improvements in removal efficiency,which has attracted wide public attention.In this paper,to obtain removal functions with high removal efficiency and stability in the polishing of optical components,an optical fabrication technology based on fixed abrasive diamond pellets(FADPs)elasticity tool(ET)is designed.The main contents of this paper as follows:(1)Based on the basic principle of computer control optical surface forming technology,we design the fixed abrasive diamond pellets elasticity tool in this paper.Meanwhile,the detail selection principle of key components and optimization process of ET are introduced.(2)According to Preston equation,combine pressure distribution model by finite element simulation,a mathematical algorithm of material removal function(RF)is proposed and optimized.In addition,the simulation model is verified by experiment.(3)Through the theoretical and experiment analysis the influence of main process parameters on the removal efficiency and surface roughness during polishing by ET.Based on the above analysis,providing a theoretical basis for choosing appropriate process parameters.(4)Several basic characteristics of the ET are analyzed by the theory and experiment,such as the stability of removal function,removal efficiency and surface roughness.Besides,an approach are designed to suppress the edge effect,which can reduce the edge width and the edge form error using the ET.Finally,the whole surface polishing test in grating path is carried out.