Preparation And Grinding Performance Of Porous Brazed Diamond Grinding Wheel

Grinding machining technology is an important field in the manufacturing technology,and grinding machining tools have become one of the key components in the field of precision machining.The grinding wheel structure in grinding machining tools is generally composed of grinding particles,binders,pores and other parts.At present,the consolidated abrasive grinding wheel manufactured by traditional technology is mostly used.The working surface of grinding wheel is very easy to be blocked and the abrasive particles fall off early,which easily leads to premature failure of grinding wheel or thermal damage during grinding and has a serious impact on the quality and efficiency of parts.Therefore,in order to solve the problems existing in grinding process,TiH₂ with brazing and hole-making is introduced in this paper,and porous brazed diamond grinding wheel is prepared by molding and vacuum liquid phase sintering.In addition,based on simulation grinding analysis,experimental research on SiC ceramic grinding of porous brazed diamond grinding wheel was carried out.And grinding performance of common compact diamond grinding wheel was compared and analyzed from grinding force,workpiece surface roughness,workpiece surface and workpiece sub-surface morphology.The main contents of this paper are as follows:The porous brazed diamond grinding wheel with porous structure was prepared by oxidation pretreatment of TiH₂ material with Cu-Sn-TiH₂ filler metal powder and diamond as main raw materials.The pore variation regularity of the grinding wheel and the influence of porosity on the change of bending strength were analyzed.The results show that porosity is positively correlated with the content of pore-forming agent,and bending strength is negatively correlated with the content of pore-forming agent.The pore-forming effect of oxidized TiH₂ pretreatment is better.When the addition amount of oxidized TiH₂ is 7.5%,the grinding wheel strength requirement can be met,at the same time,its porosity is larger and pore distribution is relatively regular and uniform.Through MATLAB and ANSYS APDL,the geometrical model of grinding wheel with random hole and abrasive grain distribution is established.The mechanical behavior of SiC ceramic material is simulated by using JH-2 material constitutive model.The process parameters are optimized for grinding wheel simulation test by applying constraints and loading loads.In this paper,the actual grinding force and the simulated grinding force are compared,and the material removal process of grinding silicon carbide ceramics with grinding wheel is studied.The results show that the errors of simulation and experiment results are within the control range,which proves the accuracy of the model.The diamond grinding wheel simulation model can be used for grinding force prediction.The SiC ceramic grinding test was completed by using the porous brazed diamond grinding wheel and the common compact diamond grinding wheel,respectively.The changing trend and causes of grinding force,workpiece surface roughness and workpiece surface/subsurface morphology with machining parameters are analyzed.The experimental results show that the normal force and tangential force are positively correlated with the workpiece feed speed and grinding depth.Reducing the workpiece feed speed and grinding depth can reduce the surface quality defects of SiC ceramics.Compared with commom sintered sleeve drill,porous brazed diamond grinding wheel is more sharp and can increase the surface quality of workpiece,which is beneficial to realize precision and low damage machining.