High-performance polymers (PSU, PEI, PEEK, PPS, LCP)

PEI (Rigid Ultem PEI)

Very high temperature, chemical and mechanical performance. Expensive; narrow processing window.

Processing temperatures

Melt (injection) temperature	370 °C
Mold surface temperature	155 °C
Ejection temperature	190 °C

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

Physical properties (typical)

Density	1.27 g/cm³
Shrinkage (flow / cross)	0.6 / 0.6 %
Specific heat	1.2 kJ/kg·K
Thermal conductivity	0.22 W/m·K

Drying

Drying is required (follow the data sheet).

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

Points to watch

High melt and mold temperature; mold heating (oil/electric)
High pressure and abrasive fillers; mold and screw material
Gas and degradation; venting and cleaning

Typical use: Aerospace, medical, electronics, chemical industry

Defects common with this material

Splay (silver streaks)

Fine silvery streaks on the part surface in the flow direction.

splay · silver streaks · moisture streaks

Brittleness / low impact strength

The part breaks more easily than expected; sometimes the surface looks fine.

brittleness · brittle part · cracking

Stress cracking

The part cracks during assembly, on contact with oil/solvent or over time; the crack usually starts at stressed areas.

stress crack · crack · environmental stress cracking

Weld line (knit line)

A line and a weak zone where two melt fronts meet.

weld line · knit line · joining line

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

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