On The Fundamental Of The Hydrodynamic Suspension Polishing Process

A new method of suspension polishing with uniform hydrodynamic pressure distribution is proposed for the atomic level super smooth surface requirements for the nanocrystalline growth substrate.The core technology of this method is the use of polishing liquid immersion workpiece,the proper viscosity of polishing solution in wedge polishing tool rotary drive,fast convergence by liquid wedge gap,the formation of hydrodynamic suspension polishing tool to maintain,abrasive and workpiece surface in a non-contact state;construct the constraint boundary field,the work stress and hydraulic pressure stability in polishing fluid shear zone.This paper adopts the theoretical calculation and numerical simulation study on flow field of hydraulic pressure suspension,explore the influence of structural parameters of the channel boundary and wedge dynamic pressure and bearing capacity of homogeneous liquid,a hydraulic model of collision particle and workpiece grinding pressure of suspension polishing,reveals the stress relaxation mechanism of workpiece surface should be built,hydraulic suspension polishing machine,and polishing experiments on single crystal copper workpiece using the polishing machine,the test of surface morphology and residual stress.1.In order to facilitate theoretical analysis,the fluid flow field is simplified to a two-dimensional structured flow field and a parallel rotating disk flow field.Based on the theory of hydrodynamic lubrication,the pressure formula and carrying capacity formula of two-dimensional structured flow field are derived.The pressure formula and carrying capacity formula are calculated by MATLAB.The analysis results show that the design of the hydraulic pressure boundary constraint suspension polishing improves parallel regional pressure uniformity;slope accounted for longer than the R higher than the size of B,slope pressure has no effect,but the uniform distribution of pressure and bearing capacity of the size effect,and when r=0.8,b=1.2,the maximum bearing capacity.2.The velocity formula and pressure formula in the flow field of parallel rotating disk are derived,and the analysis is made.The analysis results show that the velocity of parallel rotating circular polishing liquid is composed of tangential velocity and radial velocity,and the tangent velocity is far greater than that of radial velocity.The flow of the polishing fluid in the whole flow field is a spiral flow formed by the superposition of shear flow and radial radiation flow.With the increase of the radius,the pressure increases gradually,and the maximum pressure is reached at the maximum radius.3.Computational fluid dynamics(CFD)is applied to simulate the flow field of hydrodynamic pressure levitation polishing,and the distribution of fluid pressure and the velocity of abrasive particles in the processing area are extracted.The results show that in the three-dimensional flow field,the confinement boundary increases the pressure uniformity and pressure value of the fluid pressure in the parallel region.The pressure curve along the circumferential direction is highly consistent with the variation trend of the theoretical pressure curve,but the pressure at the inlet and outlet of the unit flow field is negative.4.The use of ABAQUS to establish a hydraulic model of collision particle and workpiece grinding pressure of suspension polishing,by prestressing on the workpiece to replace the residual caused by mechanical grinding stress,residual analysis of single abrasive grit and the impact of the surface stress relaxation effect.The results show that the particle velocity increases,the surface residual stress relaxation efficiency is high,but the stress relaxation area should be increased with the increase of the impact force is not uniform;the number of surface residual stress decreases to a stable value and does not change,and the higher the speed,stable value the smaller the.The grinding speed is basically related to the speed of the polishing tool disk,so the stress relaxation effect on the surface of the workpiece can be improved by improving the machining speed.5.In single crystal copper processing object,hydrodynamic suspension polishing machine for preparing super smooth surface were developed using liquid,and interference by VEECCO NT,SEM,TEM and other white instrument characterization of copper samples,compared with the traditional mechanical polishing of the sample.The results show that the hydraulic pressure of super smooth surface suspension polishing than traditional mechanical polishing can obtain the surface roughness is smaller and the surface morphology and crystal lattice integrity better.