Finite-Element Analysis of Forces in Drilling of Ti-Alloys at Elevated Temperature

Demand for high-strength alloys in aerospace, marine and off-shore industries has grown significantly over last decades, primarily thanks to their high strength, light weight as well as good fatigue and corrosion-resistance properties. However, these materials are extremely difficult to machine with conventional machining methods. Hot machining is an alternative technique used by many researchers for cutting of hard-to-cut materials in turning and milling operations. In this assisted machining technique, an external heat source is used to reduce shear strength of the machined workpiece, enhancing material removal of such alloys. Drilling is one of the most important and basic operations for producing cylindrical holes in machined components. In this work, a three-dimensional finite-element (FE) model of drilling process is developed in a commercial FE software DEFORM 3D. A nonlinear temperature-dependent material behaviour is incorporated in numerical simulations. The effect of an external heat source on thrust forces and torque on a drill-bit was investigated with the developed FE model. Advantages of hot drilling in reducing thrust force and torque reduction are demonstrated.