EFFECTIVENESS OF TWISTED NEMATIC LIQUID CRYSTALS AS WATER BASED CUTTING FLUID ADDITIVE AND TAP LUBRICANT
An experimental investigation on the performance of an emulsion of mineral oil with twisted nematic liquid crystal (cholesteryl stearate) additive when turning steel with uncoated carbide lathe tool was carried out. Cutting fluid was applied by flooding the cutting zone from low pressure coolant system of conventional lathe. Machined surface roughness and flank wear of the tool were monitored during machining tests. Experimental investigation was carried out by means of a two-factor second-order full factorial orthogonal design. The concentration of liquid crystal in cutting fluid (0.1-0.5% by volume) and cutting speed (85-267 m/min) were chosen as independent variables and surface roughness Ra was chosen as response variable. It was found that surface roughness with the cutting fluid containing liquid crystalline additive was better (decreased 1.2-fold) that with the additive-free coolant. Tool life increased 25% as compared with additive-free coolant.
Twisted nematic liquid crystals were also used as a dry-film lubricant of hand taps. It is established that liquid crystals reduce cutting torque up to 4 times as compared with grease.http://dx.doi.org/10.5755/j01.mech.17.5.738