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PEI filament

Polyetherimide

PEI is a high-performance engineering plastic, best known by the trade name ULTEM. It keeps its strength at high temperatures, resists flames and chemicals, and is used for aerospace and industrial parts, but it needs a specialist printer with a very hot nozzle and a heated chamber.

17 PEI filaments from 10 brands, in 24 colours.

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At a glance

Our rating
Ease of printing
Toughness
Stiffness
Heat resistance
Outdoor and UV
Flexibility
  • Needs an enclosure
  • Dry before printing
  • Needs ventilation

Typical settings

Median values across all PEI filaments. Always check the maker's recommendations for a specific filament.

Nozzle
340–380 °C
Bed
120–160 °C
Density
1.27 g/cm³
Max drying temperature
Not listed

Diameters: 1.75 mm (24 colours)

Colours

Popular PEI filaments

Browse all 17

Top PEI brands

About PEI

Properties

  • Very high heat resistance, with a glass transition of around 185–215 °C depending on the grade.
  • Strong and stiff across a wide temperature range.
  • Inherently flame retardant, with low smoke.
  • Good chemical resistance.
  • Usually an amber or black colour.

Good for

  • Industrial, automotive and aerospace parts under heat and load
  • High-temperature jigs, fixtures and tooling
  • Parts that must meet flame resistance requirements

Less suited to

  • Desktop printers: it needs a nozzle of around 350–400 °C and a heated chamber
  • Everyday functional parts, where PC, nylon or ASA cost far less

Printing tips

  • Nozzle around 350–400 °C, bed around 140–160 °C and an actively heated chamber; use a printer designed for high-temperature materials.
  • Dry thoroughly before printing, typically at around 120–150 °C.
  • Expect to tune carefully: warping and layer adhesion are the main challenges.
  • Ventilate well, as with all high-temperature printing.

PEI questions

Can a normal 3D printer print PEI?

No. PEI needs a nozzle of around 350–400 °C, a very hot bed and an actively heated chamber, which only industrial or specialist high-temperature printers have. On a desktop printer, PC or carbon fibre nylon are the strongest practical options.

Is PEI the same as the PEI sheet on my printer?

It is the same plastic, used differently. A PEI sheet is a thin coating that gives a grippy print surface; PEI filament is for printing parts and needs a far hotter printer.

What is ULTEM?

ULTEM is a trade name for PEI. Filaments described as ULTEM 1010 or 9085 are specific PEI grades; 9085 is blended for toughness and is common in aerospace.

What is PEI filament used for?

Parts that must stay strong at high temperatures or meet flame resistance requirements, such as aerospace interior parts, industrial tooling and high-temperature jigs.