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

Abstract

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.

Performance evaluation of spot cooled vibration assisted turning for Ti6Al4V alloy

“…Dual nozzle system with a nozzle angle of 45° to the rake face, nozzle-tip distance of 35 mm and nozzle diameter of 6 mm was used in this study. 18 In VAT and SCVAT the amplitude and frequency of vibrations were 25 µm and 20,000 Hz respectively at 100% ultrasonic power. The experimental setup and associated equipment are shown in Figure 4(a) to (e).…”

“…The machining, cooling and vibration parameters were chosen based on the tool work combination as per the tool supplier data and authors previous work. 18,30 The machining parameters were kept constant with a cutting speed of 80 m/min, feed rate of 0.25 mm/rev and 1 mm depth of cut for CT, VAT, VTSC, SCVAT to evaluate the performance of each process under similar machining conditions. The detailed machining conditions and machining environment adopted in the work are summarized in Table 3.…”

“…This nozzle configuration was chosen based on the author's previous work. 18 The nozzles were 3D printed with a 3D printer (Make and Model: Ultimaker 2+) using Poly Lactic Acid (PLA) material. The diameter of each nozzle is 6 mm and length is 30 mm as shown in Figure 3(b).…”

“…It was concluded from the study that LAMM with vortex tube reduced the average cutting force by 15% than LAMM and the burr size was reduced too. Mahapatro and Krishna 18 adopted vortex tube cooling system with CO 2 gas in machining Ti6Al4V alloy. The incorporation of vortex tube in the work led to lower temperature at the cutting zone and improved the surface finish.…”

Impacts of Burnishing Variables on the Quality Indicators in a Single Diamond Burnishing Operation

“…The VT has been widely utilized to enhance the technical performances of various machining processes. Mahapatro and Krishna [8] revealed that the CT and Ra of the VT-based turning Ti-6Al-4V were decreased by 35.6 % and 66.14 %, respectively, while the CF was increased by 18.6 %, as compared to the dry cutting. Singh et al [9] emphasized that the VT caused 45 % to 56 % lower carbon emission for the turning Ti-3Al-2.5V in comparison with the dry condition.…”