An investigation on tool performances in milling rare-earth magnesium alloys

Although rare-earth magnesium (Mg-RE) alloys are widely used in various industries, they show much poorer machinability for shaping into desired dimensions than conventional magnesium ones. The most critical issues associated with cutting Mg-RE alloys are high risk of chip ignition and short tool life dominating the chip removal process. The present paper aims to address the tool performances on the machinability of Mg-RE alloys under dry cutting. Four types of tools covering uncoated and diamond-coated ones were examined, and a special focus was devoted to explore the effects of various tool parameters on the milling responses of Mg-RE alloys as well as the underlying wear mechanisms. The experiments reveal that the cutting tools with larger rake, clearance, and helix angles can achieve high-quality milling of Mg-RE alloys at controllable cutting temperatures. The cutting parameters can be maintained at a certain level, such as the cutting speed of 120–240 m/min and the feed per tooth of 0.1–0.2 mm/z, to meet the requirements of safe milling of Mg-RE alloys without ignition risk.