Magnesium is the lightest structural metal and exhibits excellent machinability. Some of the advantages of machining magnesium compared to other commonly used metals include: • Low power required – approximately 55% of that required for Al. • Fast machining – employing the use of high cutting speeds, large feed rates and greater depths of cut. • Excellent surface finish – extremely fine & smooth surface achieved. • Well broken chips – due to the free-cutting qualities of magnesium. • Reduced tool wear – leading to increased tool life. To fully exploit and enjoy the advantages of machining magnesium, it is important that the unique characteristics of the metal are understood.

TAPPING Standard taps are suitable for small production quantities or if high tolerances are not required. For best results taps tailored to magnesium should be used. Taps should be provided with large polished flutes. HSS two flute taps with ground threads are recommended for diameters less than 4.8 mm, three flute taps for diameters up to 19mm. and four flute taps for diameters over 19mm. Taps should be ground to be concentric with the front lead or cutting portion having a clearance of about 20°. Where there is no form relief, all lands should be hooked on both sides to give a leading top rake of about 10° for entering and about 5° for backing out where required (see figure 6). When tapping holes 0.25mm diameter and smaller the operation may be done dry. Mineral oil lubricants should be used to increase tap life, increase the accuracy of threads, improve the surface finish, or if chip jamming becomes a problem.

Magnesium is the lightest structural metal and exhibits excellent machinability. Some of the advantages of machining magnesium compared to other commonly used metals include: • Low power required – approximately 55% of that required for Al. • Fast machining – employing the use of high cutting speeds, large feed rates and greater depths of cut. • Excellent surface finish – extremely fine & smooth surface achieved. • Well broken chips – due to the free-cutting qualities of magnesium. • Reduced tool wear – leading to increased tool life. To fully exploit and enjoy the advantages of machining magnesium, it is important that the unique characteristics of the metal are understood.

Machined Magnesium Part

The production of well broken chips helps with chip handling and housekeeping, this is especially beneficial when using automated or CNC machining. The production of fine swarf should be avoided due to the issues regarding flammability and the risk of ignition from the heat generated at the tool edge during cutting. Coarse chips help to take away heat from the cutting face and tool.