Environmentally friendly machining with a revolving heat pipe grinding wheel

Defects caused by high grinding temperatures on both workpieces and grinding wheels become more significant with the development of difficult-to-machine materials and creep-feed grinding procedures. The coolants normally used to dissipate heat can cause harm to the environment as well as increase machining costs. A novel idea that incorporates a revolving heat pipe into the grinding wheel has been proposed to enhance heat transfer in the contact zone. In this study, a simulation is performed to investigate the heat transfer mechanism in the evaporator and condenser section of a revolving heat pipe grinding wheel (RHPGW) at a wheel velocity of 45 m/s. The results indicate that natural convection heat transfer and film condensation occur under this condition. The heat transfer and startup performance of the RHPGW are investigated in further experiments with different working fluids, fluid loadings and rotational speeds. Finally, experiments on creep-feed grinding of Inconel 718 are performed using a RHPGW and a grinding wheel without a revolving heat pipe, without application of any coolant. The results show that grinding temperatures can be maintained below 100 °C with a RHPGW and both the workpiece and grinding wheel show better quality than those when grinding is performed without a revolving heat pipe.