Machining Magnesium

Magnesium’s specific cutting force is significantly lower than other metals, enabling high speeds (up to 3000 m/min in face milling) and large feed rates. Carbide and PCD tools are preferred for durability and superior finish. Tool geometry should feature sharp edges, large relief angles, and positive rake angles to minimize heat and chip buildup.

Magnesium is best machined dry due to its high thermal conductivity and free-cutting properties. However, cooling gases (argon, compressed air) or mineral oils may be used to manage temperature, especially in high-speed or deep-hole operations. Water-miscible coolants can be hazardous due to hydrogen generation unless specially formulated for magnesium.

Proper swarf handling is essential to minimize fire risk. Chips must be kept dry, segregated, and stored in non-combustible containers. Fine swarf should be avoided due to flammability. Recycling is feasible, especially with dry chips.

While solid magnesium is not highly flammable, fine chips can ignite. Suitable extinguishers (e.g. Met-L-X) should be on hand. Water, CO₂, and nitrogen must not be used.

Standard machining operations (turning, milling, drilling, tapping) are feasible with modifications. Careful control of parameters ensures safety, dimensional accuracy, and tool life.