Papers by Keyword: Hot Drilling

Abstract: 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.

Abstract: The aim of this paper is to investigate the behaviour in terms of drilling forces and roughness of Metal Matrix Composites (MMC) in hot drilling machining. In particular, Al2009/(SiC)_w, Al6061/(SiC)_w, and Al6061(Al₂O₃)_p metal matrix composites were used, and the adopted temperature were in the range 20°C-160°C. A comparison with drilling at room temperature has been discussed. The results have shown the sensible influence of the working temperature on drilling forces and on surface material properties. In the case of Al2009/(SiC)_w a minimum in the drilling forces has been found, making possible the dry machining and improving the cutting conditions. Instead, for Al6061/(SiC)_W and Al6061(Al₂O₃)_p in the used temperature range no minimum appears.