Thermoplastic
HDPE
Low friction, chemically inert, and tough at low temperature.
Published values for unfilled grades at 23 °C unless stated. Confirm against the supplier datasheet for the grade you specify.
What it is
HDPE is a linear polyethylene with high crystallinity. It is soft compared with engineering plastics but extremely tough, especially below freezing, where most rigid plastics turn brittle.
The surface is waxy and low friction, which makes it a good bearing and chute material, and it is inert enough for potable water and food contact.
Where it is used
- Fluid containers, tanks, and caps
- Wear strips, chutes, and low-load bearings
- Cold-service parts and outdoor components
- Cutting boards and food-contact hardware
- Machined jigs and fixtures where marring must be avoided
Processing notes
No drying needed. Melt 200–260 °C, mold 20–60 °C.
Shrinkage is the highest of the common molding plastics and highly anisotropic. Tolerances tighter than ±0.3 % of dimension are not realistic without a dedicated tooling trial.
Machined HDPE moves after cutting as internal stress relieves. Rough, rest, then finish for anything precise.
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Design notes
Expect to design around shrinkage rather than fight it: avoid long unsupported spans, and keep walls uniform.
Ultrasonic welding is unreliable. Hot plate welding and mechanical fastening work.
Like PP, nothing sticks to it without corona or flame treatment.
Grades and variants
- Injection grade, higher melt flow, thin walls
- Blow molding grade, higher molecular weight for containers
- UHMWPE, very high molecular weight, machined only, exceptional wear life
- Food and potable water certified grades
- UV stabilised black for outdoor service
Specifying this material?
Send your CAD and target volumes. We come back with a price, a lead time, and any material or design notes that would reduce either.