Influence of preheating on chatter and machinability of titanium alloy - Ti6A14V

Numerous studies on machinability of titanium and its alloys have been conducted in the past few decades with the main objective of reducing cost of machining especially of aerospace alloys. Though classified as "difficult-to-cut" materials, titanium and its alloys are attractive materials due to their unique high strength-weight ratio, which is maintained up to elevated temperatures and their exceptional corrosion resistance. In this work, an experimental investigation of the influence of workpiece preheating using induction heating has been conducted for improvements of machinability of titanium alloy Ti-6A1-4V ASTM B348. The inserts used were uncoated cemented carbide filled into a 16 mm diameter end mill tool. The cutting speeds used in these experiments were 40, 80, 120 and 160 m/min; the depths of cut were 1 and 1.5 mm and the feed rates were 0.1 and 0.15 mm/rev. Thermo-couples were used in measuring the surface temperature of work material during machining. The experiments of end milling operation conducted on Vertical Machining Center (VMC) were designed to look into the effect of preheating on chip serration and chatter, cutting force and torque, tool wear and surface finish. A comparison of the above criteria for room temperature and preheated machining was made. The results show that preheating machining improves the machinability of titanium alloy. Increased plasticity of the work material during preheating reduces the frictional forces on the tool face and the fluctuation of cutting force and also contributes to improved damping capacity of the system. As a result preheated machining results in reduction in vibration amplitudes at resonance frequencies up to 67%. An increase in cutting force and torque mean value leads to the formation of relatively thicker chips, which in turn leads to an increase in chip-tool contact length. The hottest spot on the tool is thus shifted away from the cutting edge leading to a more favourable temperature distribution in the tool. More stable cutting, longer chip-tool contact length and favourable temperature distribution in the tool helps in reducing the dynamic stresses acting on the tool. This in turn reduces the enhances of micro and macro chipping of the tool. This leads to uniform and much lower tool wear up to three times reduction in flank wear has been achieved. Lower tools wear, helps in maintaining a sharp cutting edge at the nose section and the flank areas of the tool resulting in smoother surface roughness values during preheated machining

Study of ionic liquids (AIL and PIL) viscosity and its functional groups under heat treatment on cutting tool surface using fourier-transform infrared spectroscopy (FTIR)

This study was conducted to investigate the efficiency of Minimum Quantity Lubrication (MQL) technique by using Modified Jatropha Oil (MJO) bio-based lubricant with the presence of 10% Ammonium Ionic Liquid (MJO+AIL10%) and 1% Phosphonium Ionic Liquid (MJO+PIL1%) additives respectively at various temperature of 200 ̊C, 300 ̊C and 400 ̊C heat treatment to determine the ability to exhibit corrosion and wear throughout the process. Fourier-Transform Infrared Spectroscopy (FTIR) analysis revealed prominent peaks of functional groups in these bio-lubricants; esters (C-O) and (C=O), alkanes (C-H), hydroxide (O-H), and nitrile groups deposited on the cutting tool surface. Initially, nitrile group is detected on cutting tool surface without lubricants at 2200 to 2300 absorption band reduced to lower intensity and most likely concealed by MJO+AIL10% compared to MJO+PIL1% where the nitrile group remains reflected in FTIR spectrum. In this work, it is proved that MJO+AIL10% has higher viscosity as compared to MJO+PIL1%. in the context of functional groups and supported the previous study on MJO+AIL10% as corrosion inhibitor

Evaluation of physicochemical and tribological performances of hBN/WS2 and hBN/TiO2 hybrid nanoparticles-MJO-based oil

This work aims to investigate the physicochemical and tribological performance of modified Jatropha oil (MJO) with the addition of 0.025 wt.% of hexagonal boron nitride (hBN) + Titanium dioxide (TiO2) (MJOht) and hBN + tungsten disulphide (WS2) (MJOhw). The physicochemical properties of the samples were evaluated through kinematic viscosity and viscosity index. Four ball test was used to determine the tribological performance of the samples. All the MJO samples were compared with the benchmark oil, Synthetic Ester (SE). The result revealed that MJOht has excellent physicochemical properties in kinematic viscosity of 20.79 mm2/s at 40 °C and 6.29 mm2/s at 100 °C. MJOht also had the highest viscosity index (288). For tribological performance, MJOhw has an excellent coefficient of friction (COF) (0.0574) and lowest surface roughness (Ra) (0.11 μm)., while MJOht shows a smaller mean wear scar diameter (MWSD) (718.6 µm). Overall, MJO with hybrid additives shows excellent performance on physicochemical and tribological properties and making it a feasible choice as a green metalworking fluid

Performance Evaluation of Palm-Olein TMP Ester Containing Hexagonal Boron Nitride and an Oil Miscible Ionic Liquid as Bio-Based Metalworking Fluids / Amiril Sahab Abdul Sani ...[et al.]

Bio-based lubricants from vegetable oils are seen as a great potential alternative to the ever declining petroleum oil sources. Vegetable oils are highly biodegradable and non-toxic, pose good lubricating properties and do not require high production costs. Palm oils as the main renewable oil sources in Southeast Asia are being widely used as cooking oils. Researches have been conducted to expand their potential usage as lubricants for manufacturing applications. In this study, a chemically modified palm olein trimethylolpropane (TMP) ester (MRPO) containing various additives has been tested for their tribological characteristics. Two types of additives; hexagonal boron nitride (hBN) nanoparticles as solid lubricants and phosphonium-based ionic liquid (PIL) as an oil-miscible liquid additive were added into the MRPO to enhance its physical and tribological properties. Four ball wear tests were performed on steel/steel contacts lubricated with each of the lubricant samples. The experimental results presented improved physical properties as well as good antiwear and antifriction performances of the lubricant mixtures compared to the base oil. A minute quantity of PIL (1 wt. %) and hBN nanoparticles (0.05 wt. %) are found to increase the tribological performance of the MRPO, as well as when they are mixed together as lubricant additives into the base oil. The tribological improvements posed by the MRPO+PIL1% revealed better than or comparable results to the conventional synthetic ester and therefore is seen suitable for the use as a new advanced renewable bio-based metalworking fluid for manufacturing activities that corresponds to the energy saving benefits and environmental concerns

Physical characterization of modified palm oil with hybrid additives nanofluids

The common use of petroleum-based metalworking fluids (MWFs) in industry harms the environment and human beings. The biggest disadvantage of RBD palm oil is its low thermal-oxidative stability. As a result, the goal of this research is to create an innovation for palm oil based MWFs. The new creation of modified palm oils (MPOs) has been produced by a transesterification process with palm methyl ester to trimethylolpropane molar ratios of 3.5:1. Later, at a concentration of 0.025wt.%, the MPOs were mixed with single and hybrid additives such as activated carbon (AC) (MPOa), tungsten disulphide (WS2) (MPOw) and hybrid AC with WS2 (MPOaw). The physicochemical parameters of MPOs were studied, including viscosity, and acid value. The physicochemical properties were evaluated as per ASTM standards over a period of 4 weeks to check the state of lubricant and observable changes in the properties during this period According to the findings, MPOaw shows enhanced thermal (high viscosity index 365-387) and oxidative stability (lubricant storage). Moreover, MPOaw recorded has higher antioxidant properties that can help prevent or slow down the oxidation process, reducing the production of acids and subsequently lowering the acid value (0.14 -0.19 mg NaOH/g). In conclusion, it has been proven that MPOaw has the best performance and the potential to have a positive effect on the industry as a sustainable MWF for machining processes

Performance evaluation of uncoated carbide tool in high speed drilling of Ti6Al4V

This paper presents the experimental investigation into the performance of the uncoated carbide tool when high speed drilling (HSD) of Ti6Al4V. Machining responses such as thrust force, torque, vibration, chip formation and surface integrity of drilled surface were evaluated at various cutting conditions. Results show that cutting speed and feed significantly influenced the above responses. Folded wavy type chips and curly type chips were produced under all tested cutting conditions. It was also found that the transition from aperiodic to periodic chip formation occurred as the cutting speed increases. In addition, improvement of the drilling performance was also recorded as a result of reduction of acceleration amplitude during peck drilling method was adopted. Observation on the subsurface of the drilled workpiece indicates a severe plastic deformation at all tested cutting conditions

Evaluation of physicochemical and tribological performances of hBN/WS2 and hBN/TiO2 hybrid nanoparticles-MJO-based oil

This work aims to investigate the physicochemical and tribological performance of modified Jatropha oil (MJO) with the addition of 0.025 wt.% of hexagonal boron nitride (hBN) + Titanium dioxide (TiO2) (MJOht) and hBN + tungsten disulphide (WS2) (MJOhw). The physicochemical properties of the samples were evaluated through kinematic viscosity and viscosity index. Four ball test was used to determine the tribological performance of the samples. All the MJO samples were compared with the benchmark oil, Synthetic Ester (SE). The result revealed that MJOht has excellent physicochemical properties in kinematic viscosity of 20.79 mm2/s at 40 °C and 6.29 mm2/s at 100 °C. MJOht also had the highest viscosity index (288). For tribological performance, MJOhw has an excellent coefficient of friction (COF) (0.0574) and lowest surface roughness (Ra) (0.11 μm)., while MJOht shows a smaller mean wear scar diameter (MWSD) (718.6 µm). Overall, MJO with hybrid additives shows excellent performance on physicochemical and tribological properties and making it a feasible choice as a green metalworking fluid

Study of Ionic Liquids (AIL and PIL) Viscosity and its Functional Groups under Heat Treatment on Cutting Tool Surface Using Fourier- Transform Infrared Spectroscopy (FTIR)

This study was conducted to investigate the efficiency of Minimum Quantity Lubrication (MQL) technique by using Modified Jatropha Oil (MJO) bio-based lubricant with the presence of 10% Ammonium Ionic Liquid (MJO+AIL10%) and 1% Phosphonium Ionic Liquid (MJO+PIL1%) additives respectively at various temperature of 200 C, 300 C and 400 C heat treatment to determine the ability to exhibit corrosion and wear throughout the process. Fourier-Transform Infrared Spectroscopy (FTIR) analysis revealed prominent peaks of functional groups in these bio-lubricants; esters (C-O) and (C=O), alkanes (C-H), hydroxide (O-H), and nitrile groups deposited on the cutting tool surface. Initially, nitrile group is detected on cutting tool surface without lubricants at 2200 cm−1 to 2300 cm−1 absorption band reduced to lower intensity and most likely concealed by MJO+AIL10% compared to MJO+PIL1% where the nitrile group remains reflected in FTIR spectrum. In this work, it is proved that MJO+AIL10% has higher viscosity as compared to MJO+PIL1%. in the context of functional groups and supported the previous study on MJO+AIL10% as corrosion inhibitor