High-efficiency Magnetorheological Finishing Of Inner Surface Of Hemispherical Shell Resonator

The hemispherical resonant gyroscope(HRG)has many conspicuous advantages,such as high accuracy and good stability.In the research and manufacturing of HRG,there is a big gap between the domestic and the world's advanced level.One of the main reasons for the poor accuracy of HRG is that the hemispherical shell resonator(HSR)parts as the main components of HRG are not processed accurately.HSR is a complex structural part machined from hard and brittle materials with high precision requirements.There are two kinds of polishing methods for HSR in domestic.One is processing of molding abrasive tools or similar molding abrasive tools,and the other is processing of the ball end tools combined with multi-axis machine tools.The machining accuracy and the processing efficiency of these two methods are difficult to meet the requirements,and there are many problems.The inner surface of the HSR is analyzed in this paper.The principle of magnetorheological finishing(MRF)is combined with the basic theory of grinding and polishing.MRF technology is tried to be applied to HSR's polishing.Four major factors which were magnetic field simulation analysis,processing scheme design and analysis,process parameter optimization experiment,conditions for uniform material removal analysis and HSR internal surface processing experiment were used to analyze the feasibility of MRF application in HSR's polishing process.The main work and results were as follows:(1)In accordance with the construction of the inner surface of the HSR,annular magnetorheological finishing method is proposed.Through the magnetic field simulation,it is determined that the magnetic field excitation scheme is a multi-magnet annular arrangement.Parameters such as magnet specifications,magnet materials,and excitation gaps were determined.Based on this,a reasonable processing plan was designed.And through the analysis of the motion relationship and geometric relationship of the machining process,the feasibility of the processing scheme is preliminarily determined.(2)The effect of the effect of magnetic field intensity,polishing head rotation speed,gap between the work piece and the polishing head and abrasive size was explored with the method of single factor experiment.The orthogonal experiment method was used to study the effects of the spinner speed,machining gap,magnetic induction and abrasive grain size on the processing performance.The results illustrate that the polished performance of the ring polisher is approximately stable.When the processing conditions were that the magnetic field was strong,the rotation speed was 350 rpm,the gap was 0.6 mm and the abrasive particle size was 0.5 to 1 ?m the optimum polishing effect can be obtained.(3)The machining relative motion relationship and the simplified mathematical model of MRF are comprehensively analyzed.The results show that the uniformity of axial material removal of the part is affected by the speed of the shaft of the polishing head and the speed ratio of the part shaft.The radial material removal uniformity of the part is affected by the complexity of the relationship between the polishing head axis and the part shaft speed.And choose the right speed ratio to improve the sphericity of HSR parts.(4)After properly simplifying the machining process,the internal surface polishing process of HSR parts is carried out on a biaxial machining work platform.The results reveal that the proposed method can improve the surface quality and sphericity of HSR parts.