Publication

Abstract : The present work evaluates the opportunity to replace the non-biodegradable and skin unfriendly commercial cutting fluids by glycerol based lubricants. Micro (graphite, GRT) and nano (reduced graphene oxide (RGO) and zinc oxide, ZnO) carbonaceous and non-carbonaceous friction modifiers (FMs) were dispersed in glycerol (GLY). The tribological properties of the dispersions were assessed by tests on four ball tribometer and the results were compared against commercial cutting fluid (C.F). It was observed that GLY samples exhibited excellent antiwear properties as compared to C.F. The COF in case of GLY samples were about 20–60% less and WSD was about 75–80% less than C.F. The lowest COF was exhibited by graphite (0.1 wt %) dispersed glycerol samples followed by reduced graphene oxide (0.1 wt %) and zinc oxide (0.08 wt %), indicating the better performance of carbonaceous additives than non-carbonaceous additive. In order to assess their performance in real time machining operations, turning was carried out using EN 24 workpiece on lathe machine under intermittent lubricant flow. The surfaces of the tribo-pairs and the chips formed were analyzed using high end microscopes and profilometer. The micro Raman spectra indicated the tribo film formation on the wear tracks. The morphology of the chips (particularly graphite) formed during turning operation was similar to those of commercial cutting fluid. Carbonaceous nanoparticles additive glycerol samples exhibited the best performance with respect to the machined surface quality without any sign of damage similar to the C.F. Additionally, the roughness of the work piece after machining was similar in case of C.F (1.550 μm), 0.1% GRT (1.358 μm) and RGO (1.442 μm) dispersed glycerol. Thus, the present work indicates that glycerol additivated with optimum proportions of micro and nano particles is a plausible green alternative to non-biodegradable and skin unfriendly commercially available synthetic cutting fluid.