Influence of flow parameters in the dual nozzle CO2-based vortex tube cooling system during turning of Ti-6Al-4V

Dual nozzle vortex tube cooling system (VTCS) is developed to improve the machinability of Ti-6Al-4V where cold-compressed CO2 gas is used as a coolant. The cooling effect is produced by the process of energy separation in the vortex tube and the coolant is supplied into the machining zone to remove the generated heat in machining. In this study, the responses such as cutting force (Fz), cutting temperature (Tm), and surface roughness (Ra) are analyzed by considering coolant inlet pressure, cold fraction, and nozzle diameter as input variables. Further optimization is performed for the input variables using the genetic algorithm technique, and the results at optimum conditions are compared with those of dry cutting. From the results, lower cutting force is observed at lower coolant pressure and cold fraction and higher nozzle diameter. The cutting temperature is minimized by increasing coolant pressure and cold fraction and by decreasing nozzle diameter. A better surface finish is observed at high coolant pressure and cold fraction and lower nozzle diameters. It is observed from the response surface method (RSM) that the coolant pressure is most significantly affecting all the responses. At optimum conditions, the cutting temperature and surface roughness are 35.6% and 66.14%, respectively, lower than dry cutting due to the effective cooling and lubricating action of the CO2 gas, whereas cutting force observed under the VTCS is 18.6% higher than that of dry cutting because of the impulse force of the coolant VTCS and thermal softening of the workpiece in dry cutting.

Modelling and optimization of magnesium alloy milling parameters

In the pursuit to lighter, less consuming products, manufacturers, especially in aviation and automotive industries, are turning more and more to using lightweight alloys such as the ones based on magnesium. Higher requirements for increased productivity have led to concepts like high-speed machining (HSM), high feed machining (HFM) or high-efficiency machining. Tighter regulations concerning requiring for more environmentally friendly industrial processes led to limitations in the use of cooling liquids and a search for cooling methods with less impact (dry cutting, cryogenic cooling, near dry machining and others). Better machining processes can only be achieved by modelling and optimization. This paper briefly presents the results obtained by our research team concerning the modelling and optimization attempts on face milling of magnesium alloys using different methods: design of experiments (e.g. factorial design, response surface method), fuzzy logic or neural networks.

Hard Turning ASSESSMENT on EN31 Steel in Dry and Wet Cooling Environments USING Grey-Fuzzy Hybrid Optimization APPROACH

In recent years, machining of hard-to-cut metals by hard turning process is an embryonic technology for machining industry and research development. Hard turning is generally defined as the material removal process of hardened steel having hardness greater than 45 HRC. The current research presents a comparative hard turning investigation on EN 31 (56 ± 1 HRC) grade steel using physical vapor deposition (PVD) coated carbide tool under dry and wet cooling. The selection of a better cooling strategy among dry and wet cooling was based on the value of obtained surface roughness (Ra) and material removal rate (MRR) in hard turning. Wet cooling exhibited better performance over dry cutting as lower Ra and greater MRR are achieved with wet cooling. Further, considering Taguchi L16 orthogonal array, hard turning experiments were executed in wet cooling and responses like surface roughness (Ra), material removal rate (MRR), and diameter error were studied. Further, the Grey-fuzzy hybrid optimization tool was employed and found improved results relative to the alone grey relational analysis as about 9 % less Ra and 2.612 times more MRR is noticed at the grey fuzzy optimal set of parameters.

MQL-Assisted Hard Turning of AISI D2 Steel with Corn Oil: Analysis of Surface Roughness, Tool Wear, and Manufacturing Costs

Precision hard turning (HT) gained more and more attention in the cutting industry in the last years due to continuous pressure of the global market for reducing costs, minimizing the environmental and health issues, and achieving a cleaner production. Therefore, dry cutting and minimal quantity lubrication (MQL) became widely used in manufacturing to meet the environmental issues with respect to harmful cutting fluids (CFs). Vegetable oils, in MQL machining, are a promising solutions to petroleum-based CFs; however, the effects and performance on surface roughness and tool wear in HT with ceramic inserts remain unclear. To address this limitation, hardened AIDI D2 steel and pure corn oil, rich in saturated and monounsaturated fatty acids, cheap and widely available, have been used to conduct dry and MQL experiments at different cutting speed and feeds. Results show that corn oil is suitable as cutting lubricant in HT, creating a strong anti-wear and anti-friction lubricating film which improves the roughness with 10–15% and tool life with 15–20%, therefore reducing costs. Best surface roughness values (Ra = 0.151 μm, Rz = 0.887 μm, Rpk = 0.261 μm) were obtained at 180 m/min and 0.1 mm/rev. The analysis of variance shows that corn oil has statistical significance on roughness, validating the results.

Analysis and Optimization of Cutting Tool Coating Effects on Surface Roughness and Cutting Forces on Turning of AA 6061 Alloy

The present work has been focused on cutting force (Fc) and analysis of machined surface in turning of AA 6061 alloy with uncoated and PVD-TiB2 coated cutting inserts. Turning tests have been conducted on a CNC turning under dry cutting conditions based on Taguchi L18 (21 × 33) array. Kistler 9257A type dynamometer and equipment have been used in measuring the main cutting force (Fc) in turning experiments. Analysis of variance (ANOVA) has been applied to define the effect levels of the turning parameters on Fc and Ra. Moreover, the mathematical models for Fc and Ra have been developed via linear and quadratic regression models. The results indicated that the best performance in terms of Fc and Ra was obtained at an uncoated insert, cutting speed of 350 m/min, feed rate of 0.1 mm/rev, and depth of cut of 1 mm. Moreover, the feed rate is the most influential parameter on Ra and Fc, with 64.28% and 54.9%, respectively. The developed mathematical models for cutting force (Fc) and surface roughness (Ra) present reliable results with coefficients of determination (R2) of 96.04% and 92.15%, respectively.

Optimization of multiple quality characteristics for end milling under dry cutting environment using desirability function

Milling AA6082T6 materials is a difficult venture because of their heterogeneity and a slew of problems, inclusive of surface roughness, that get up for the duration of the machining method and are connected to the material’s homes and slicing settings. The optimization of machining parameters is a crucial section inside the manufacturing method. This research introduces a unique approach for improving machining settings whilst milling aluminum alloy. A technique notorious as desirability function analysis (DFA) turned into worn to optimize machining parameters. DFA is a effective tool for optimizing multi-reaction problems. Milling research for aluminum alloy were completed using tungsten carbide end milling inserts in dry situations, based totally on Taguchi’s L9 orthogonal array. Multi-response issues, along with machining pressure and surface roughness, are used to optimize machining parameters including feed charge, spindle speed, and depth of reduce. person desirability values from the desirability characteristic analysis are used to create a composite desirability cost for the multi-responses. The most effective ranges of parameters had been discovered based at the composite desirability fee and substantial contribution of parameters has been determined the usage of analysis of variance.

Comparative assessment of hard turning under dry and minimum quantity lubrication

Hard turning with CBN and ceramic inserts is commonly regarded as a cost-effective alternative to grinding. However, there have been few studies comparing hard turning with low-cost carbide tools to high-cost CBN and ceramic cutting tools. However, when it comes to the usage of cutting coolant during severe turning, there are mixed outcomes. In this study, a PVD-coated TiSiN-TiAlN carbide tool was used to hard turn AISI 52100 steel in a dry and MQL environment. Through multi-objective optimization, a comparative assessment in terms of surface roughness, cutting force, and tool life under various cutting settings is provided. In terms of three components of cutting force, surface roughness, and tool life, mathematical models were constructed to forecast and improve machining performance. Under both dry and MQL conditions, the study discovered an optimal cutting speed of 108 m/min, a feed value of 0.09 mm/rev, and a depth of cut of 0.16 mm. Under MQL, hard turning produced optimal surface roughness and tool life of 0.88 m and 64 minutes, respectively. In comparison to hard turning under dry cutting, the optimal surface roughness was 1.07 m and the tool life was 49 minutes. Under MQL, tool life increased by over 31%, according to the findings of the experiments. Under dry and MQL conditions, however, no significant differences in cutting forces and surface roughness were identified.

Optimizing the Machining performance of CNC tools inserts coated with Diamond like Carbon Coatings under the dry cutting environment

In this research work we have coated WC (tungsten carbide) tool inserts with diamond like carbon coatings. The deposition was done using the thermal Chemical Vapour Deposition (CVD) method. We have used bagasse of sugarcane which is an agriculture waste as a carbon precursor for developing the diamond like carbon coatings. Surface finish, cutting temperature and cutting forces of as-developed diamond like carbon coatings on the WC inserts were examined and analyzed in this research work. For confirming the presence of diamond like carbon coatings on the surface of coated tungsten carbide (WC) tool inserts substrate we have used Raman spectroscopy, X-ray diffraction (XRD) and Field Emission Scanning Electron Microscope (Fe-SEM). The increase in the hardness on the developed coated samples were inspected by performing the hardness test on the coated substrates. The average evaluated Vickers Hardness number were found to be 1455.24 HV and 950.65 HV for both coated as well as un-coated samples respectively. This shows 53% rise in the hardness of the un-coated WC inserts.