A Thermal Model to Predict Tool Temperature in Machining of Ti–6Al–4V Alloy With an Atomization-Based Cutting Fluid Spray System

Abstract

In this study, a heat transfer model of machining of Ti–6Al–4V under the application of atomization-based cutting fluid (ACF) spray coolant is developed to predict the temperature of the cutting tool. Owing to high tool temperature involved in machining of Ti–6Al–4V, the model considers film boiling as the major heat transfer phenomenon. In addition, the design parameters of the spray for effective cooling during machining are derived based on droplet–surface interaction model. Machining experiments are conducted and the temperatures are recorded using the inserted thermocouple technique. The experimental data are compared with the model predictions. The temperature field obtained is comparable to the experimental results, confirming that the model predicts tool temperature during machining with ACF spray cooling satisfactorily.

Electrohydrodynamic Atomization for Minimum Quantity Lubrication (EHDA-MQL) in End Milling Ti6Al4V Titanium Alloy

“…In contact with hot surfaces, water-based coolant evaporates, forming a vapor barrier between the cutting zone and coolant due the Leiden frost effect [52]. In machining titanium, the cutting temperature is higher than the Leiden frost point of water [13]. Therefore, film boiling is the governing heat transfer mechanism [13].…”

“…In machining titanium, the cutting temperature is higher than the Leiden frost point of water [13]. Therefore, film boiling is the governing heat transfer mechanism [13]. Moreover, low pressure flood cooling system of the machine tool is aimed at flooding the cutting zone instead of penetrating the chip-tool contact area.…”

“…Minimum quantity lubrication (MQL) has also gained significant attention as an alternative to conventional flood cooling [11,12]. Tanveer et al [13] suggested using ultrasonic atomization for MQL turning of Ti6Al4V. Tascioglu et al [14] investigated various cooling and lubrication methods for high speed turning of Ti-5553 titanium alloy at 90 and 120 m/min cutting speeds.…”

Delayed Leidenfrost Effect of a Cutting Droplet on a Microgrooved Tool Surface

“…Especially in the process of metal cutting, due to the severe friction between the tool and workpiece, a large amount of heat is generated, so a cutting fluid is employed to take the heat away and improve the machining performance. 13,14 However, it should be noted that the Leidenfrost effect of cutting fluid at the machining area is inevitable, 15 which makes the cutting fluid boil in a film regime and largely decreases the heat transfer efficiency, 16,17 thus inducing a decline in the quality of the machined surface, waste of cutting fluid, and even environmental pollution. Herein, it is of great importance to explore and suppress the Leidenfrost phenomenon of cutting fluid at the interface during the metal cutting process.…”

“…When a liquid droplet falls on the solid surface with a temperature much higher than the boiling point, a thin vapor layer forms at the contact interface, which keeps the droplet suspended and slowly evaporate, known as the Leidenfrost effect. − It is worth noting that the Leidenfrost effect widely exists in the heat dissipation process of high heat flow density parts, including the cooling of electronic devices, , the combustion of liquid fuels, , and the spray quenching, , which obviously affect the heat transfer and dissipation efficiency. Especially in the process of metal cutting, due to the severe friction between the tool and workpiece, a large amount of heat is generated, so a cutting fluid is employed to take the heat away and improve the machining performance. , However, it should be noted that the Leidenfrost effect of cutting fluid at the machining area is inevitable, which makes the cutting fluid boil in a film regime and largely decreases the heat transfer efficiency, , thus inducing a decline in the quality of the machined surface, waste of cutting fluid, and even environmental pollution. Herein, it is of great importance to explore and suppress the Leidenfrost phenomenon of cutting fluid at the interface during the metal cutting process. − …”