| Magnetorheological polishing technology is an ultra-precision processing method that uses the rheology of magnetorheological polishing fluid to polish in a magnetic field.The quality of magnetorheological polishing fluid has a great influence on the speed and effect of semiconductor workpiece polishing.Due to the difference in density between the solid particles and the base carrier liquid in the polishing liquid,the two-phase force of the magnetorheological polishing liquid is different during the polishing process,and the solid particles are unevenly distributed,that is,the solid-liquid separation phenomenon,which seriously affects the service life of the polishing liquid and Workpiece polishing effect.Aiming at the problem of solid-liquid separation of magnetorheological polishing fluid,this paper studies the influence of porous media and various polishing parameters on the fluidity and solid-liquid separation of polishing fluid,and analyzes the reasons for the problem of solid-liquid separation of magnetorheological polishing fluid from a theoretical perspective.The fluid dynamics simulation method was used to study the solid-liquid two-phase fluidity and the degree of solid-liquid separation of the magnetorheological polishing fluid under different conditions.The main research contents and results of this article are as follows:Theoretically analyze the force of the magnetorheological polishing fluid and its internal iron particles,derive the liquid level distribution function of the polishing fluid equilibrium state,analyze the reasons for the solid-liquid separation of the polishing fluid and determine the main factors that affect the solid-liquid separation of the polishing fluid According to the basic fluid dynamic equations in the rectangular coordinate system,the fluid dynamic equations in the cylindrical coordinate system and the hybrid model fluid dynamic equations suitable for the magneto-rheological polishing fluid flow analysis are derived.The momentum equation of the polishing fluid flow in the porous medium is solved,and the calculation formulas of the viscosity resistance coefficient and the inertia resistance coefficient of the porous medium are derived.According to the flow principle of magnetorheological polishing fluid,a CFD model of magnetorheological polishing fluid flow was established,the multiphase flow setting of the polishing fluid was set,and the resistance of porous medium was added in the initial area of the polishing fluid.Magnetic field simulation was performed using Maxwell software Field coupling.The simulation compares the degree of solid-liquid separation of the polishing fluid with and without porous media,analyzes the effect of porous media on the fluidity of the magnetorheological polishing fluid and the degree of solid-liquid separation,and explores the porosity and pore size of the porous media The influence of polishing fluidity and solid-liquid separation degree.Simulate and analyze the distribution of solid-liquid two phases and the degree of solid-liquid separation of the magneto-rheological polishing liquid under different base carrier fluid viscosity,iron particle diameter,and polishing disc speed,and combine the theoretical analysis of base carrier fluid viscosity,iron particle diameter and polishing disc speed The rule of influence on the degree of solid-liquid separation of polishing liquid.Comparing the distribution of the polishing liquid at different times and the degree of solid-liquid separation with and without magnetic field,the effects of magnetic field settings on the fluidity of the polishing liquid and the degree of solid-liquid separation were explored. |
