Study On The Influence Of Surface Microstructure Of CVD Diamond Wheel On The Flow Field Of Grinding Fluid And Chip Removal Process

CVD diamond grinding wheel is a new grinding tool which uses chemical vapor deposition(CVD)method to grow microcrystalline diamond coating with specific thickness on tungsten carbide and other matrix materials.This new type of grinding tool has the characteristics of having no binder,high abrasive density,complex structure,no size limitation and good wear resistance,which makes CVD diamond grinding wheel have great application prospect in micro-grinding and ultra-precision grinding.However,with the continuous deepening of related processing technology research,CVD diamond grinding wheel increasingly highlights the following main constraints: on the one hand,CVD diamond grinding wheel has a high abrasive density,the grinding processing area is in a close state,and the grinding fluid is difficult to reach the grinding area for cooling and lubrication during processing.On the other hand,the chip space of CVD diamond grinding wheel is small,and the chip is not easy to be discharged during grinding,resulting in easy blockage on the surface of the grinding wheel.It is an effective way to improve the cooling and chip removal performance of grinding zone by machining regular three-dimensional structure on grinding wheel surface by pulsed laser.Based on this,this thesis designed a surface structured CVD diamond micro-grinding wheel for micro-machining and a surface structured CVD diamond disc grinding wheel for planar ultra-precision grinding from the aspects of changing the grinding fluid flow field and chip removal process in the grinding zone.The following researches were carried out.Firstly,the overall structure of the structured CVD diamond micro-grinding wheel used for micro-machining and the CVD diamond disc grinding wheel used for planar ultra-precision grinding was designed,and the structural pattern and main structural parameters of the surface microstructure of the grinding wheel were determined.The statics model of CVD diamond micro-grinding wheel was established,the strength and stiffness of CVD diamond micro-grinding wheel were checked,and the influence law of various surface microstructure parameters on the structure strength and stiffness of CVD diamond micro-grinding wheel was obtained.Secondly,according to the two kinds of grinding wheel structure size,the fluid simulation software Fluent was used to establish the macro and micro models of the flow field in the grinding zone of the micro wheel and the flow field model in the grinding zone of the plane grinding wheel,and analyzed the influence of the grinding wheel surface microstructure parameters and grinding parameters on the grinding fluid flow field in the grinding zone.Thirdly,based on the shape and size of grinding chips under different grinding conditions,combined with the flow field model of grinding zone and DPM discrete phase model,the chip removal models of grinding wheel in different grinding processes were established,and the influence rule of surface microstructure parameters on the grinding wheel chip removal process was obtained.