Study On The Technology Of Magnetorheological Polishing Of Ni-P Alloy Coating Aspheric Surface

With the rapid development of science and technology in China,the requirements for optical elements are higher and higher.Especially in the field of polishing and grinding of aspherical optical elements,the manufacturing technology of aspherical mirror encounters the bottleneck of processing,and the traditional processing method is difficult to meet the needs of the current stage in practical application.In order to solve the problems of low machining accuracy and poor surface quality in traditional machining,many new optical machining methods have emerged.Magnetorheological machining technology plays an increasingly important role in the field of optical machining because of its highly deterministic processing method.However,Ni-P alloy coating is widely used in the field of optics as a modified layer.There is a lack of in-depth study on the optical processing method of this coating,and many of them are processed by traditional polishing process.Based on the demand of practical engineering for rapid and low-cost manufacturing of Ni-P alloy coated aspherical surface,this paper studies the key technologies in the process of Ni-P alloy coated aspherical surface magnetorheological polishing,and finally determines the process flow of Ni-P alloy coated aspherical surface magnetorheological processing,and actually completes the processing of a piece of off-axis aspherical mirror,which is fast for Ni-P alloy coated aspherical mirror Fast low cost manufacturing provides related technical support.The main research work of this paper includes:(1)The definition and characteristics of electroless plating are briefly introduced.The physical and chemical properties and deposition principle of electroless plating Ni-P alloy coating are analyzed.The phosphorus content and related heat treatment process suitable for coating in optical processing are determined.The preparation method of Ni-P alloy coating on the optical surface of the mirror in the laboratory is introduced;(2)The removal mechanism of Ni-P alloy coating by MRF was studied.This paper summarizes several basic theories of material removal mechanism of polishing,and studies the relevant removal models combined with the material characteristics of Ni-P alloy coating.Lay a theoretical foundation for the follow-up study;(3)Several important parameters,such as rotation speed of polishing wheel,concentration of polishing powder,polishing gap and polishing time,which affect the polishing efficiency and surface quality in MRF polishing are selected.Orthogonal experiments are carried out by using orthogonal thought.The edge effect of MRF polishing was also studied.Finally,the optimal parameter group of aspheric mirror is determined by optimizing the experimental data;(4)The actual processing of Ni-P alloy coated aspheric mirror was carried out.The main application of MRF combined with CCOS technology,after the pure working time of 21 hours four-wheel MRF,the surface shape of the workpiece(RMS)is reduced from 0.196 ? to 0.024 ?,and the condition of knife marks caused by SPDT machining is also greatly improved.The final surface roughness value(Ra)is 2.62 nm,which meets the requirements of optical polishing and realizes high efficiency and high precision machining.