Search

To solve the limited cooling capacity of drip cooling technique in current clinical grinding orthopedic surgery, this paper carried out a nanoparticle jet minimum quantity cooling grinding experiment by using hydroxyapatite, SiO2, Fe2O3, carbon nanotubes nanofluids. The mass fraction of each nanofluids was 2%, 4%, 6%, 8%, 10%, respectively. Grinding temperature during the grinding process was measured, and results show that the temperature peak of bone micro-grinding isn't always proportional to the mass fraction of nanofluids. The measured temperature peak shows an inversely proportional relationship with the mass fraction of nanofluids within a certain mass fraction range, but a proportional relationship beyond this mass fraction range. Such a critical mass fraction varies when using different types of nanoparticles. Combined with heat transfer enhancement of nanofluids, the influence law of nanofluids type and concentration on grinding temperature was disclosed from the rheological properties of nanofluids and the micromechanisms of nanoparticles in the grinding zone. The bigger the mass fraction, the more easily it displays rheological properties. As for hydroxyapatite, whose length-diameter ratio is high and for SiO2 and CNTs, whose hardness values are high, they more easily display shear thinning and shear thickening, and the effect of rheological properties on temperature is obvious. [ABSTRACT FROM AUTHOR]

The present research investigated the lubrication performances of AlO/SiC nanofluid minimum-quantity lubrication (MQL) grinding in accordance with recent technologies used in conducting minimum-quantity lubrication grinding with nanofluids. The mean grain size of the AlO and SiC nanoparticles (NPs) was set to 50 nm, and the difficult grinding Ni-based alloy was used as the workpiece material in the experiment. Grinding force was measure by using a three-component dynamometer and then used to calculate grinding force ratio ( R). Workpiece surface roughness was measured by a roughness tester. Five groups of NPs were mixed with synthetic lipids at a mass fraction of 6 %. The lipids were then used as the grinding fluid for the nanofluid MQL grinding. Results showed that, compared with pure SiC NPs, pure AlO NPs obtained lower R = 0.3, lower specific grinding energy ( U = 75.93 J/mm), and lower surface roughness ( Ra = 0.386 μm), indicating better lubrication performance. The mixed NP consisting of AlO and SiC NPs achieved even lower R and surface roughness than pure NPs because of the 'physical synergistic effect.' The optimal ratio of the effect of mixed NPs was explored based on this finding. The AlO/SiC (2:1) mixed NPs obtained the smallest R = 0.28 and specific grinding energy ( U = 60.68 J/mm), thus indicating the best lubrication performance. Therefore, 2:1 is the optimal ratio for mixed NPs. [ABSTRACT FROM AUTHOR]