Research on specific cutting energy reduction and wear resistance in thermally assisted dry-cutting with coated tools

Inconel 718 alloy has excellent performance in aerospace equipment, but due to its difficult machining characteristics, it requires excessive processing energy consumption and faster tool wear. However, this is difficult to adapt to the current carbon-neutral clean production conditions, thermal-assisted processing technology uses natural gas, a clean energy source, to heat the workpiece and reduce energy consumption during the cutting process. In this study, a dry-cutting study was carried out under thermally assisted machining conditions using TiAlN-coated tools. Thermal-assisted machining by preheating the workpiece material to soften the material locally, and then machining operations such as cutting were conducted. Under the action of heat, the yield strength of the material is reduced, the residual stress during the processing is controlled, the work-hardening phenomenon is reduced, and it is easier to cut. The coating technology is to coat the surface of the tool with a thin layer of inert material to achieve the effect of protecting the tool material. The temperature transfer during the cutting process was analyzed while considering the cutting speed, coating thickness and thermal contact resistance. Through the analysis of the experimental results, there is an inverse correlation between the transfer of cutting heat and the hot working temperature. This is because the increase in temperature reduces the cutting force, weakens the contact between the chip and the tool surface, and reduces the heat transfer. Different coating thicknesses are not positively related to temperature transfer, but the existence of coatings can indeed reduce heat transfer. This study found that the combination of coating technology and thermal-assisted machining technology can improve the cutting process, the specific cutting energy can be reduced by 507 N/mm 2 (26.9%), the tool substrate temperature can be reduced by 203 °C (53%), and the tool wear can be reduced by 21.2 × 10 −8 mm (19.5%) when the coating thickness is 1 μm.