Investigations of Tribological Behaviour in Machining Operation for a Single Point Cutting Tool in Presence of Coolant

Abstract

Dry turning is considered environmentally safe but the manufacturing rate may be slow due newlineto the effect of combined machinability parameters (i) speed, (ii) feed and (iii) depth of cut. newlineThe cutting tool has relative velocity insitu contact with the workpiece. The possibility of newlinesticking material and plastic deformation of the cutting tool may be increased. The surface newlinemorphology may get affected due to adhesive particles and other cutting parameters and newlinefinally dimensional accuracy of workpiece depends on the same. Conventional cutting fluids newlinemay be used to smoothen the process but do not show more remarkable improvement due to newlinerecent development of new hard engineering materials and strict high standards of newlinemanufacturing. Straight oils and mineral oils were used by researchers at the interface of newlinecutting tool and workpiece but lubrication was found more effective than cooling. Servocut newlinecutting oils with water emulsions were used but the majority of conventional cutting fluids newlineprovided marginal improvement in machinability characteristics like surface roughness, tool newlinewear, surface morphology etc. The need was found for the preparation of novel cutting fluid newlineand supplied in the control way to the cutting tool surface to prevent wastage. Therefore, newlinecutting fluids with nanoparticles were developed of Al2O3and TiO2 separately in distilled newlinewater of 1.0%W/W separately. Biocompatible (Tween 20) surfactant was used for preventing newlineagglomeration of particles. Nano-cutting fluids were used on pin-on-disc tribometer for newlinedetermining tribological properties during sliding and on lathe machine for observing newlinemachinability characteristics. Cryogenic cooling was done with a direct supply of LN2 at the newlineinterface of pin-on-disc of tribometer and the rake surface of single point cutting tool on lathe newlinemachine. Tribological properties and machinability characteristics of prepared nano-cutting newlinefluids were compared with dry, wet, and cryogenic cooling condition. newlineIt has been found that the lowest value coefficient of friction and specific wear rate was found newlineat direct supply LN2 and increasing order with nano-cutting fluid with nanoparticles TiO2 newlinetribometer. The coefficient of fiction was 0.93 and specific wear rate was 4.365X10and#8722;5 newlinemm^3 newline/Nm during the dry sliding condition. On comparing with the dry condition, coefficient newlinefriction was lowered by 4.3%, 12.9%, 15% and 17.2% for wet with conventional cutting newlinefluid, nano-cutting fluid TiO2, nano-cutting fluid Al2O3and cryogenic cooling with LN2 newlinerespectively. On comparing with a dry condition, specific wear rate was lowered by 22.5%, newline29.5%, 37.92% and 98.5% for wet with conventional cutting fluid, nano-cutting fluid TiO2, newlinenano-cutting fluid Al2O3and cryogenic cooling with LN2 respectively. newline` newlinexvii newlineSurface roughness, flank wear length, cutting force, temperature, machining time and chip newlinecompression ratio were found at 1.85µm, 245µm, 110N, 127°C, 49.31seconds and 2.3 newlinerespectively during dry turning and declined by 30.27%, 54.28%, 49.09%, 53.54%, 30.26% newlineand 54.35% during cryogenic cooling on comparing with respective values during dry newlinemachining condition. It was found that values of machining properties were higher during dry newlinemachining condition and followed by decreasing pattern as (i) dry, (ii) wet, nano-cutting fluid newlinewith TiO2, nano-cutting fluid with Al2O3 and cryogenic cooling with LN2. It has been found newlinethat wastage is associated with liquid nitrogen due to its property and boiling point newlinetemperature of -196°C. During experimentation, the contact of liquid nitrogen with the newlineatmosphere at room temperature created white fumes. This gave a need for the development newlineof an alternative cooling process. A controlled and localized process was developed for newlinesupplying the conventional cutting fluid and nano-cutting fluids drop by drop at the interface newlineof pin-on-disc tribometer and cutting insert-workpiece on lathe machine. The results of newlinerigorous experiments showed that nano-cutting fluid with Al2O3 was better than dry, wet, newlinenano-cutting fluid with TiO2 and cryogenic LN2. The wastage of nano-cutting fluid has been newlinefound very low or negligible as compared with cryogenic cooling with LN2. newline newline