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With the increasing demand for high precision micro parts in machining field, the development of micro hole drilling technology, especially the finite element simulation technology is rapidly promoted. However, there are many limitations in the simulation of micro-drilling, such as element size, computational efficiency, chip forming, etc. In the present work, a finite element software, Abaqus has been used to simulate the thermal-mechanical coupling micro-drilling process of titanium alloy material, and the key technologies, such as twist bit modeling, material constitutive model, chip separation criterion and element division, were investigated. Through simulation, it was found that with the increase of rotational speed and the decrease of feed speed, chip shape gradually fragmented, in addition, thrust force and torque diminished. Since chip shape, thrust force and torque are important factors affecting drilling quality and tool life, the work could offer important guiding significance for cutting parameter optimization.

Cutting temperature is essential to improve machining technology in micro drilling of hard material. As the unreasonable temperature distribution will increase the complexity of tool-workpiece surface contact, affect the machining quality of tool and the surface integrity of hole wall. In this paper, the cutting process model is combined with the analytical temperature rise model based on time to study the change rule of surface contact conditions. The 40Cr sample was used to carry out drilling experiments. The results show that the high feed micro drill tool is prone to structural differences at high temperature, large area size effect. It makes the contact conditions change significantly, and the heat distribution of system changes, which affects the stability of cutting.