Optimal Design And Experiment Of The Untethered Magnetic Magnetic Manipulation Polishing

With the application of aluminum alloy free-form surface parts in the diversity of industries,higher requirements for the surface quality are needed.Ultra-precision polishing technology is widely used in ultra-precision manufacturing due to its diverse processing methods and excellent results.The existing polishing methods have several limitations in the processing of the small-caliber cavities and the complex curved cavities.In this paper,a untethered magnetic manipulation polishing device is proposed,and the polishing solution,polishing path and the process parameters are optimized through experiments.The specific contents are as follows:1.Based on the theory of dynamic magnetic field,the method of untethered magnetic manipulation polishing is proposed.The dynamic magnetic field drives the internal polishing tool to move and rotate,and the polishing solution generates a vortex flow at the same time.The polishing particles in the solution are pressed by the polishing tool to generate pressure on the parts to achieve polishing.The structure of the device is designed which is divided into untethered magnetic system and polishing work system.The magnetic field generated by the external permanent is theoretically analyzed and simulated using Comsol Multiphysics software,the torque and magnetic force of the polishing tool are analyzed.2.According to the requirements of the device,previous studies and experiments,the composition and ratio of the new magnetic polishing solution are determined:200nmFe₃ O₄ powder with a mass fraction of 10%,5?m alumina abrasive grain with a mass fraction of 15%,L64 mixed with a small amount of L64 with 2%mass fraction as a surfactant,lithium magnesium silicate with 0.5%mass fraction as a thixotropic agent,a small amount of aluminum hydroxide as a pH adjuster and DMDMH antibacterial agent added into deionized water.The preparation process of the magnetic polishing solution is determined.3.Based on the research of traditional polishing trajectory,a new raster path for free-form surfaces is proposed.The maximum spacing value D=8mm is determined based on the uniformity of path.To prevent regular surface errors because of repeated stacking along the same path during polishing,the offset path polishing method is proposed to polish multiple times,the offset t=2mm and the polishing times m=4 are determined.The speed of the polishing tool during quasi-static operation v=0.01m/s is determined by the total material removal amount h=5?m based on the shape error of the surface.It is verified by experiments that the polishing tool has the ability to move stably along the grating path on planes at different angles and surfaces.4.Univariate optimization experiments for polishing parameters are carried out to determine the polishing time,the speed of the polishing tool and the polishing force.Based on the polishing parameters,the polishing process and the polishing path,the inner curved surface is polished.The surface roughness of the surface before polishing is 0.276?m,and the roughness of the polished area after polishing is measured as0.043?m,0.067?m and 0.077?m.It is verified that the surface roughness value and topography after polishing are improved,the vortex polishing device can be used to polish the free-form surfaces.