Temperature of Grinding Carbide with Castor Oil-based MoS2 Nanofluid Minimum Quantity Lubrication

Nanofluid minimum quantity lubrication (NMQL) has better stability, higher thermal conductivity, and excellent lubrication performance compared with traditional flood lubrication. The heat transfer model and finite difference model were established to verify the feasibility of NMQL conditions in grinding cemented carbide. Based on them, the grinding temperature of cemented carbide is calculated numerically. Results show that the grinding zone temperatures of flood grinding and NMQL are lower, 85.9 °C and 143.2 °C, respectively. Surface grinding experiments of cemented carbide YG8 under different working conditions are carried out. Dry grinding (227.2 °C) is used as the control group. Grinding zone temperatures of flood grinding, minimum quantity lubrication, and NMQL decrease by 64.2%, 39.5%, and 20.4% respectively. The error is 6.3% between theoretical calculation temperature and experimental measurement temperature. Based on machining process parameters (specific grinding force, force ratio) and experimental results (microstructure of grinding wheel, workpiece, and grinding debris), the effects of different working conditions on wheel wear are studied. NMQL achieves the highest G ratio of 6.45, the smallest specific grinding force, and the smallest Fn/Ft ratio of 2.84, which further proves that NMQL is suitable for grinding cemented carbide.

Estimation of Grinding Cycle Time Taking into Account Specific Grinding Force

In the grinding process, due to the elastic deformations of grinding machine and grinding wheel, the ground depth of cut is smaller than the applied depth of cut. Consequently, the ground depth of cut has to be controlled in spark-out grinding process. However, the cycle time in spark-out grinding process is not easy to be estimated. From such a viewpoint, in this study, using specific grinding force obtained by measured grinding force in the first spark-out pass, a calculating method of the real ground depth in continuous pass process is proposed. And, this method is experimentally evaluated.