Assessment of surface structure optimization in internal cooling grinding

For the purpose of solving the problems about grinding heat affecting workpiece surface quality during grinding Inconel 718, a novel internal cooling grinding wheel with phyllotaxis distribution of abrasive grain family is proposed in this paper. The coolant outlet shapes of replaceable abrasive ring are designed into waist-shaped and circular to investigate the influence of the surface structure on grinding performance. Then, CFD method is used to analyze the flow field distribution characteristics in grinding zone under different outlet shapes and rotation speeds. Finally, grinding experiments are carried out on Inconel 718. The simulation results reveal that the flow field distribution of the waist-shaped outlet is smoother and wider. The blind area of coolant is less that the maximum reduction is 54.61% compared with circular outlet. The increased rotation speed accelerates the flow rate of coolant at the outlet under the same outlet shape, without obvious effect on the fluid distribution range. The experimental results demonstrate that compared with the external flood cooling, internal cooling has excellent cooling and heat transfer capacity because of the avoidance of the air barrier effect. With the same internal cooling, the waist-shaped outlet has better grinding performance. When the rotation speed rises from 1000 to 3000 rpm, the maximum reduction of grinding temperature, surface roughness, and surface microhardness are 24.92%, 26.81%, and 4.09%, respectively. The maximum increase of surface residual compressive stress is 13.31% (about 80.73 MPa).