Analysis Of Grinding Fluid Hydrodynamic Effect In Internal Grinding Of CBN Grinding Wheel

The status of grinding machining as an important method is more and more high in modern machinery manufacturing industry.The goal of high quality and low cost is the enterprise to pursuit now.In the grinding process,the surface quality of workpiece,grinding wheel wear and replacement is the key to achieve this goal.The pressure of grinding fluid will affect the grinding fluid flow through the grinding zone and the accuracy of grinding workpiece.The size of film thickness of grinding fluid will affect the lubrication effect and the lubricating conditions directly affect the grinding temperature,adhesive wear in the grinding zone,wear of non working abrasive grains of grinding wheel and many other elements such as the workpiece surface quality.So the hydrodynamic pressure effect of the internal grinding of vitrified bond CBN grinding wheel,the effect of surface topography on the grinding fluid pressure and film thickness when thermal effects are considered,the grinding hydrodynamic pressure effect of different grinding wheels and grinding fluid and the influence of grinding wheel vibration on time-dependent hydrodynamic pressure effect in grinding zone are studied to find the method of reducing the friction and wear of the grinding wheel,the heat of friction,the times of grinding wheel dressing,increasing the life of the grinding wheel,debasing the surface roughness of the workpiece and improving the surface quality of the workpiece.First of all,the hydrodynamic pressure model is established according to the actual situation of the internal grinding and the lubrication theory.The grinding fluid pressure and film thickness in grinding area are studied when it is the isothermal condition.The pressure and film thickness are compared and analyzed when there is grinding fluid injection pressure and no grinding fluid injection pressure.The variations of grinding fluid pressure and film thickness with the grinding fluid injection pressure,grinding wheel linear speed and radial grinding force are discussed.Secondly,considering the effect of temperature in grinding process,the thermal effect Reynolds equation and the film thickness equation are used considering the surface roughness.The effect of temperature on the grinding fluid pressure and film thickness in the grinding process is discussed when grinding the workpiece.The influence of the coupling of the grinding wheel and the workpiece surface on the pressure and film thickness is studied.Then,through the viscosity and density calculation model of nanofluids,calculation model of heat capacity,thermal conductivity,the fluid pressure and film thickness producing from grinding of five commonly used abrasive grinding wheels,the change of maximum pressure,minimum film thickness and maximum temperature of grinding fluid(nanofluids)produced by different abrasive grinding wheels with the volume fraction of nanoparticles added,the pressure and film thickness of the grinding fluid(nanofluids)added with different nanoparticles are analyzed..Finally,according to the vibration phenomenon in grinding process,the vibration function of grinding wheel is established,by using the time-dependent and thermal effect Reynolds equation,the change of the maximum pressure,the minimum film thickness and the maximum temperature with the amplitude,frequency of the vibration and wheel speed are analyzed in the grinding process.