Polyethylene (PE)

PE-LLD (Linear Low-Density PE)

Low cost, good chemical resistance, flexible (LD) or rigid (HD). High shrinkage: there is a large directional shrinkage difference.

Processing temperatures

Melt (injection) temperature220 °C
Mold surface temperature35 °C
Ejection temperature75 °C

Typical values. They vary (±) with grade and manufacturer; see the data sheet.

Physical properties (typical)

Density0.93 g/cm³
Shrinkage (flow / cross)2.5 / 2.5 %
Specific heat2.3 kJ/kg·K
Thermal conductivity0.34 W/m·K
Latent heat of crystallization (approx.)145 kJ/kg

Drying

Usually no drying is required.

For exact conditions see the material data sheet. Drying guide →

Points to watch

  • High shrinkage, prone to warpage
  • Sink marks in thick sections of large parts
  • Cooling time can become longer because of crystallization

Typical use: Caps, crates, containers, pipes, toys

Defects common with this material

Warpage

The part distorts or bends after it leaves the mold.

warpage · distortion · bowing

Sink mark

A dent on the surface opposite a thick section; the surface is drawn inwards.

sink mark · depression · sink

Dimensional variation and shrinkage differences

Part dimensions fall outside the tolerance or vary from cycle to cycle.

dimensional error · shrinkage · out of tolerance

Short shot (incomplete fill)

The cavity does not fill completely; the farthest or thinnest area of the part stays incomplete.

incomplete fill · underfill · non-fill

Flash

Plastic escapes through the parting line or around the ejector pins.

flash · overflow · parting line flash

Other grades in the same family

PE-LD (Low-Density PE)

Semi-crystalline, polyolefin210 °C melt · 35 °C mold

PE-HD (High-Density PE)

Semi-crystalline, polyolefin235 °C melt · 40 °C mold

Do the values for this material not match your grade? and we will correct them.