Research On Grinding And Polishing Trajectory And Surface Quality Of Elastic Matrix Abrasive Tools

The ultra-precision grinding and polishing technology based on elastic matrix tools has significant characteristics such as high grinding and polishing efficiency,small surface and subsurface damage,strong adaptability to workpiece surface shape,and good controllability of the grinding and polishing process.It can meet the machining requirements of low damage and high integrity workpiece surfaces.However,currently,the technical means used for ultraprecision grinding and polishing are basically "slow work producing fine work" that improves surface quality at the cost of sacrificing processing efficiency.There are still significant limitations for the processing of complex surface structures with steep surfaces and multiple curvatures,as well as difficult to machine material components.Therefore,in the precision and ultra-precision machining process of difficult to machine materials,"shape control and controlled manufacturing",which ensures material removal efficiency while taking into account surface accuracy,surface quality,and subsurface damage,has been one of the common key issues that need to be solved in this field for a long time.This article is based on the grinding and polishing technology of elastic matrix abrasive tools,and conducts research on grinding and polishing trajectory planning for machining objects with various surface features such as planes,free surfaces,and symmetric rotating aspheric.From a micro scale,it explores the mapping relationship between effective abrasive particles,stress fields,velocity fields,and abrasive particle motion trajectories and grinding and polishing paths in the elastic contact machining area,we optimized the grinding and polishing process parameters of elastic abrasive tools based on surface processing quality and material removal efficiency.The rationality of the optimization method proposed in this study was verified through experiments based on multiaxis CNC and robot platforms.The specific content of this study includes:1.Based on Hertz elastic contact theory and Preston equation material removal model,the grinding and polishing mechanisms of elastic abrasive tools under different conditions of flat and curved surfaces were analyzed.For the process of plane grinding and polishing,parameters such as the relative area proportion and coefficient of variation of abrasive particle motion trajectory in the elastic contact area between the abrasive tool and the workpiece were introduced to quantitatively evaluate the uniformity of abrasive particle motion trajectory distribution and its impact on the surface quality of the machining;For the process of surface grinding and polishing,the contact state between the abrasive tool and the workpiece is kept constant by controlling the change of grinding and polishing advance angle,and the reasonable values of the feed step length and path spacing of the abrasive tool are determined,verifying the feasibility of the complex free form surface grid trajectory planning algorithm.2.A multi-axis CNC machining platform based on elastic abrasive tools has been established.Aiming at the process of plane grinding and polishing,quartz glass was used as the processing object,and the effects of different process parameters on material removal efficiency and surface quality of the workpiece were studied through orthogonal experiments;For the surface grinding and polishing process,complex free form GH4169 nickel-based alloy blades were used as the processing object.The surface roughness,material removal efficiency,and surface shape accuracy of the processed workpiece were obtained through grinding and polishing experiments,verifying the rationality of the algorithm.3.Based on the grinding and polishing platform of parallel robot,a modified Archimedes spiral path planning algorithm is proposed to solve the problem of uneven material removal caused by the constant row spacing of the traditional Archimedes spiral,and the path planning algorithm is optimized through the multi-objective optimization algorithm,providing technical method support for high-quality and efficient grinding and polishing processing of the robot platform.