CNC Machining Materials

Magnesium

At a glance

Processes

CNC Mill
CNC Lathe

Lead Time

As fast as 10 days

Finishing Options

Vibratory Tumbling, Media Blasting, Powder Coating

Tolerance

With drawing: as low as +/- 0.005 mm No drawing: ISO 2768 medium

About the Material

Magnesium, a common material for die casting, is increasingly popular for CNC machining becaust it is lightweight and highly machinable in terms of feed rates. Machined magnesium also produces excellent surface finishes due to shorter chips being produced during the machining process. Fictiv offers multiple Magnesium alloys: AZ91D, AZ61B, and AZ31B. Each has slightly different properties, but AZ91D is the most commonly used in die casting and CNC machining.

Material Properties

AZ91D Magnesium

Yield Strength (tensile)

22,000 PSI

Elongation at Break

3%

Hardness

Brinell 63

Density

1.81 g/cm^3
0.07lb / in^3

AZ61B Magnesium

Yield Strength (tensile)

33,000 PSI

Elongation at Break

16%

Hardness

Brinell 60

Density

1.8 g/cm^3
0.07lb / in^3

AZ31B Magnesium

Yield Strength (tensile)

29,000 PSI

Elongation at Break

15%

Hardness

Brinell 49

Density

1.77 g/cm^3
0.06lb / in^3

Material Finish

Magnesium is very similar to most grades of aluminum in terms of overall appearance. Magnesium can be media blasted or tumbled to achieve a multitude of surface finishes. Additionally, powder coating can be applied to achieve more matte/glossy colors.

Design Recommendations

Min Wall Thickness

0.5 mm (0.02 in)

Min End Mill Size

0.8 mm (0.03 in)

Min Drill Size

0.5 mm (0.02 in)

Max Part Size

1200 x 500 x 152 mm [x,y,z] (mill) 152 x 394 mm [d,h] (lathe)

Undercuts

Square profile, full radius, dovetail profiles

Radii : Depth

Depth must not exceed 12x drill bit diameter. For end mills, depth must not exceed 10x tool diameter.

Cost Saving Tip

To reduce costs, limit the number of part setups, the number of inspection dimensions or tight tolerances, and deep pockets with small radii.

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