Design Of Flow Channel And Research On Grinding Performance Of Internal-cooling Slotted Grinding Wheels

In the grinding process of hard-to-machine materials such as nickel-based superalloys,due to poor thermal conductivity and high grinding temperatures,if the heat in the grinding arc zone cannot be transferred in time,the surface of the parts will be damaged,such as grinding burns and surface cracks.At the same time,the severe abrasion of the grinding wheel and the serious adhesion of the debris also affect the machined surface quality of the parts.Because of the high-speed rotation of the grinding wheel,the gas barrier layer is formed around it,which prevents the coolant from entering the grinding arc area to participate in cooling,lubrication and scouring,thus limiting the efficiency of heat exchange and affecting the quality of the machined surface.Therefore,it is of great practical value to explore efficient cooling technology and study the grinding wheel with better cooling effects for improving the surface quality of difficult-to-machine material.Based on the jet impact technology,internal-cooling technology and intermittent grinding technology,the pressurized internal-cooling slotted grinding wheels with different channel structure were designed through the simulation analysis of the flow field and temperature field.Subsequently,the wheels were prepared to carry out the grinding experiments of nickel base superalloy,and the effect of channel on grinding performance was studied.The key point of this paper is as follows:(1)According to the previous research results of the group,two kinds of channel structure of internal-cooling slotted grinding wheels are designed based on the working principle of the pressure internal-cooling technology and the slotting technology of intermittent grinding.The fluid model of the grinding wheel channel is established to study the effect of diameter on the grinding fluid velocity at the outlet of the channel.(2)The simulation model of the flow field and temperature field of a pressurized internal-cooling slotted grinding wheel applied to a plane grinding is established,and the flow characteristics of grinding fluid in the grinding arc area and the heat transfer of the grinding wheel are analyzed.The influence of grinding fluid pressure and grinding wheel speed on the distribution and speed of flow field at different outlet locations,shapes and the arrangement of abrasive grains is studied.On the basis of the analysis of the early flow field,the outlet pressure of the flow passage is taken as the entrance parameter of the temperature field analysis.Under the conditions of different grinding fluid pressure and speed,the influence of the shape and outlet position of the flow channel and the pattern of the abrasive particle on the temperature distribution of the grinding wheel is explored.Thus,the structure of the flow channel is optimized to achieve the effect of rapid heat transfer and cooling in the grinding process.The factorial method is used to optimize the grinding fluid pressure and wheel speed,so as to reduce the workload of subsequent experiments reasonably.(3)In accordance with the actual proportion of 3D printing wheel body,it is installed in the machine tool for sealing detection.Internal cooling slotted surface grinding wheel with different runner shape and abrasive grain layout type were prepared,whereafter,an experimental study was conducted on the grinding of a nickel-base superalloy GH4169 by a pressurizzed internal-cooling slotted grinding wheel.The single factor design method is adopted;the grinding temperature and work-piece surface quality under diverse grinding fluid pressure and rotation speed of grinding wheel were analyzed.