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.

Experimental Research on Heat Transfer Performance in MQL Grinding With Different Nanofluids

An investigation into the effect of nanofluid minimum quantity lubrication (MQL) on the temperatures in surface grinding is presented and discussed. Six types of nanoparticles, namely molybdenum disulfide (MoS2), zirconium dioxide (ZrO2), carbon nanotube (CNT), polycrystalline diamond, aluminum oxide (Al2O3), and silica dioxide (SiO2), are considered to mix individually with a pollution-free palm oil in preparing the nanofluids. A commonly used Ni-based alloy was chosen as the workpiece material. It is shown that CNT nanofluid results in the lowest grinding temperature of 110.7°C and the associated energy proportionality coefficient of 40.1%. The relevant physical properties of the nanofluids such as the coefficient of thermal conductivity, viscosity, surface tension, and the contact state between the droplets and workpiece surface (contact angle) were discussed to shine a light on their effect on the cooling performance. A mathematical model for convective heat transfer coefficient was then developed based on the boundary layer theories.

Machining response of Ti64 alloy under Nanofluid Minimum Quantity Lubrication (NFMQL)

Rapid wear progression of cutting insert associated with attainment of excessive tool-tip temperature are indispensable causes which limit operational domain of cutting velocity during dry turning of Ti64 alloy. Again, to counteract demerits of flood cooling, jet of air-oil mist (MQL technology) is employed in which water-based coolants or vegetable oils are highly preferable. On the other hand, inclusion of nano-additives within base fluid, and supply the same through MQL system (NFMQL) is also a trendy area of research. Application potential of NFMQL is understood over conventional MQL in terms of better cooling, and lubrication effects due to improved thermo-physical, and tribological properties of the resultant cutting fluid. In this context, present study aims to assess performance of MQL jet containing biodegradable Jatropha oil (carried by pressurized air) when applied during longitudinal turning of Ti64 work alloy. In addition, advantages of 2D layered-structured graphene nanoplatelets (when dispersed into Jatropha oil), in purview of machining performance on difficult-to-cut Ti64 alloy under NFMQL, are studied in this work. Experimental data are compared on the basis of different lubrication conditions (dry, conventional MQL, and NFMQL). Morphology of tool wear is studied in detail. The work extends towards studying chip morphology and machined surface finish of the end product, as influenced by variation in lubrication conditions.