CNC Machining Materials

HDPE

At a glance

Processes

CNC Mill
CNC Lathe

Lead Time

As fast as 3 days

Colors

White, black

Tolerance

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

Price

$

Applications

plugs and seals, electrical insulator

About the material

High-density polyethylene (HDPE) is a slippery plastic that is often machined into plugs and seals. It is also an excellent electrical insulator as well as being moisture and chemically-resistant.

Material Properties

Tensile Strength

4,000 PSI

Elongation at Break

500%

Hardness

Rockwell R65

Density

0.958 g/㎤
0.035 lbs / cu. in.

Maximum Temp

180° F

McMaster Part Number

8619K611

Material Finish

HDPE is a naturally opaque white because of its crystalline structure, but is also available dyed black in more limited stock sizes. It has a waxy finish leveraged for low-friction applications.

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 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.

HDPE FAQs

Can you CNC HDPE?

Yes, you can CNC HDPE. High-density polyethylene (HDPE) is a slippery plastic that is moisture and chemical-resistant.

What is HDPE used for?

HDPE is often machined into plugs and seals. It is an excellent electrical insulator that has a waxy finish suited for low-friction applications.

What are the advantages of HDPE?

Advantages of HDPE include good low temperature impact resistance and excellent chemical resistance. It is a high-quality, stiff and durable material that is affordable

What are the disadvantages of HDPE?

The disadvantages of HDPE are that it is susceptible to stress cracking and higher mould shrinkage, and also has lower stiffness compared to polypropylene.

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