Simulation Design And Experimental Study Of Permanent Magnet Scroll Polishing Device

With the rapid development of advanced manufacturing technologies such as aerospace,medical equipment and automobile lightweight,aluminum alloy parts have become key parts in structural devices due to their advantages such as low density,high strength,good conductivity and thermal conductivity.However,many aluminum alloy parts with free-form surface have complex structure and shape,and the precision of their inner surface is high.The existing polishing methods have many limitations on the cavity polishing of free-form surfaces.In view of this situation,this paper takes advantage of the characteristics of fluid polishing,controls the rotation of magnetic agitator in the workpiece through magnetic operation,realizes the magnetic polishing fluid vortex flow,and achieves the polishing effect.Specific research contents are as follows:(1)Based on the research of magnetic field generator,a permanent magnet field vortex polishing device is designed based on the principle of magnetic ring drive.The device design process mainly includes permanent magnet selection design,magnetic stirring device design and magnetic polishing fluid preparation.In this paper,the rectangular permanent magnet with hole and magnetic stirrer made of N35 ndfeb were selected,and the square permanent magnet was fixed on the outer rotor which can rotate with the motor to generate rotating space magnetic field.The magnetic agitator inside the workpiece to be tossed includes a magnetic agitator and a limit device,which limits the displacement of the magnetic agitator and enables it to drive the magnetic polishing fluid to rotate in the center of the container of the workpiece to be tossed.Finally,the preparation of magnetic polishing fluid was studied and its composition and ratio were analyzed.(2)The AC/DC module in COMSOL Multiphysics software is used to simulate and analyze the rotating magnetic field device.Firstly,the magnetic force of the magnetic agitator is analyzed by the horizontal and vertical arrangement of the square permanent magnet on the fixed outer rotor.Then the magnetic torque of the agitator was analyzed in the circular arrangement of permanent magnet under four conditions: double opposite,double three,four and eight.By comparing the magnetic force and the magnetic torque of the magnetic agitator,the optimal arrangement of the external square permanent magnet was determined.Finally,the rotation conditions of the magnetic agitator are analyzed and the relation between the initial rotation Angle and the position height is obtained.(3)The CFD module in COMSOL Multiphysics software was used to analyze the polishing effect of the inner surface of the container.Firstly,the two-phase flow flow analysis was carried out on the magnetic polishing fluid and its magnetic abrasive particles,and the concentration concentration of the polishing abrasive particles on the inner surface of the container was analyzed.Then the velocity of magnetic polishing fluid in the container was analyzed.In this paper,the velocity of abrasive particles on the inner surface of the container is analyzed on the premise of the rotation velocity of internal magnetic agitator,and the one-dimensional curve of abrasive particle velocity on the inner surface of the container is drawn.(4)Using PRESTON's empirical equation,the material removal function model of vortex polishing device was established.Through the previous flow simulation study of the magnetic polishing fluid,the data relationship between the pressure parameters,flow velocity parameters and magnetic agitator speed on the inner surface of the workpiece to be tossed can be obtained.The data curve is fitted by MATLAB software,and the fitting formula of related parameters can be obtained.Finally,experiments were carried out on different rotating speeds of each group of magnetic agitators,and the experimental removal rate of each group was obtained.By comparing the theoretical removal rate,the proportional coefficient Kp in PRESTON's empirical equation was obtained by MATLAB least square method,so as to establish the material removal function model.