Anisotropy in Chip Formation in Orthogonal Cutting of Rolled Ti-6Al-4V

The increasing demand for titanium alloys in aerospace and medical device industries stems from their lightweight and high strength properties. Enhancing machining technologies for titanium alloys is critical for reducing production time and costs. This study investigates the anisotropy in machining of rolled titanium alloy plates with orthogonal cutting tests. The mechanical properties of these plates exhibit anisotropy due to the rolled texture of hexagonal close-packed (HCP) structure. Observations of chip morphologies and cutting forces are conducted with changing cutting direction angles relative to the rolling direction. The result shows that the chip morphology is influenced by the cutting direction angle. When cutting parallel to the rolling direction with an orthogonal cutting tool with 30-deg rake angle, serration free chips are produced, while perpendicular cutting results in serrated chips. The chip thickness, the serration pitch, and the serration length vary with the cutting direction angle. The serration length is associated with an anisotropic deformation index, which characterizes anisotropic behavior in chip formation. Lower index values suppress the formation of undesirable serrated chips. It is expected that the anisotropic deformation index will be applied to the control of serrated chip formation in practical machining processes.