Titanium alloy is being increasingly applied to parts and structures in many fields, such as aerospace engineering, marine engineering, and bio-engineering, because of its superior properties, including light weight, high specific strength, and corrosion resistance. However, machining this alloy is very difficult because of premature tool failure, low thermal conductivity, and low removal rate. Recently, several studies have been done on titanium alloy machining in turning and milling, but these were only tried on square end mills. At the same time, radius end mills have been developed to machine three-dimensional shapes with accuracy and high efficiency. Therefore, this paper reports on our investigation into the performance of a radius end mill in terms of cutting titanium alloy. The study is based on the calculation of a cutting crosssectional area, using 3D-CAD and experiments involving inclined surface machining with contouring paths. First, the modeling of a cutter, an edge, and a workpiece with an inclined surface are carried out using 3D-CAD. Second, the uncut chip to be removed is defined by the interference of the tool and the workpiece models, and the cutting cross-sectional area is calculated based on the interference of the rake surface and the uncut chip volume. Third, experiments are performed under the conditions of stepped up and down pick feeds with up and down milling. The cutting force and surface roughness obtained through the experiments are investigated and compared under the various cutting conditions mentioned above. Experiments are also carried out for carbon steel, and the cutting performance of the radius end mill is discussed for both materials.
