CNC Machining Materials

Acrylic

At a glance

Processes

CNC Mill
CNC Lathe

Lead Time

As fast as 2 days

Colors

optically clear, opaque

Tolerance

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

Price

$

Applications

tanks, panels, and optical applications

About the material

Acrylic is a scratch-resistant plastic, available optically clear or opaque. It is often used for tanks, panels, and optical applications.  It can be somewhat brittle in thin walled areas, so it is not recommended for delicate or complex geometries.

This plastic is also known as PMMA, an abbreviation of its full chemical name, polymethyl methacrylate, as well as by the trade names Plexiglas and Lucite.

Material Properties

Tensile Strength

8,000 PSI

Elongation at Break

6%

Hardness

Rockwell M95

Density

1.19 g/㎤
0.043 lbs / cu. in.

Maximum Temp

170° F

McMaster Part Number

8560K274

Material Finish

Acrylic is transparent or opaque (black, white, and a variety of colors) in its unfinished state.  Clear acrylic will take on more of a frosted translucent appearance when machined, though can be smoothed again to an optically clear state using various finishing methods.

Design Recommendations

Min Wall Thickness

0.5 mm

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 drill bit 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.

Acrylic FAQs

Can CNC cut acrylic?

Yes, acrylic is a common material used in CNC machining. Acrylic is a scratch-resistant plastic, which in thin-walled areas can be fairly brittle. For this reason it isn’t ideal for parts that require delicate or complex shapes.

What are some CNC acrylic cutting tips?

These five tips will help you avoid difficulties and maintain a smooth cut when using CNC to cut acrylic:

  1. To avoid vibration, make sure the workpiece is properly secured.
  2. Use a bit specifically designed to cut acrylic.
  3. Larger bit sizes tend to perform best
  4. Cut at a steady rate through the acrylic as quickly and steadily as you can while maintaining control.
  5. Keep the acrylic cool by putting it in a freezer for an hour prior to making the cuts.

What are common uses for acrylic in CNC?

Acrylic is transparent and is frequently used as a lightweight substitute for glass or for light pipes. Other uses include plastic parts such as car lights, light tubes, tanks, panels and optical applications.

What is the cutting speed for acrylic?

At least 18,000 RPMs is the recommended speed for cutting acrylic. Although higher speeds are possible, you may need to adjust your feedrate to prevent the material from melting from the heat. This also depends on the diameter of the tool being used.

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