PEEK 3D Printing Guide: Nozzle, Chamber and Crystallinity

What is PEEK?

PEEK (polyether ether ketone) is a semi-crystalline thermoplastic in the PAEK (polyaryl ether ketone) family. Its glass transition temperature is about 143 °C and its melting point about 343 °C. Because it retains mechanical strength at high temperature, resists chemicals and hydrolysis, and offers a high strength-to-weight ratio, it is used as an alternative to metal parts in aerospace, defence, energy, medical and automotive applications.

Processing PEEK by material extrusion (FDM/FFF) makes it possible to produce one-off or low-volume parts in this material without tooling investment. However, PEEK has a much narrower process window than standard filaments; the result depends as much on the printer's thermal environment as on the material itself.

What makes PEEK difficult to 3D print?

High melt temperature: Depending on the grade, PEEK is usually printed at nozzle temperatures of 360 – 420 °C. The extruder must hold this temperature steadily over long job cycles.
Thermal shrinkage and warping: The larger the difference between the hot melt and its surroundings, the higher the internal stresses; large, thin-walled parts tend to lift from the bed and warp.
Interlayer bonding: If the previous layer has cooled too far, the new layer cannot bond sufficiently and the part remains weak in the layer direction.
Moisture: PEEK absorbs moisture from the air. Moist material causes bubbles, surface defects and loss of strength.

Crystallinity and chamber temperature

Much of PEEK's high-temperature performance and chemical resistance comes from its crystalline structure. If the print environment stays well below the glass transition temperature, the material cools quickly and freezes in a largely amorphous state. Amorphous PEEK is typically dark amber and translucent, while crystalline PEEK is opaque and beige; amorphous parts have lower heat resistance.

As the chamber temperature approaches and exceeds the glass transition temperature, the material cools under conditions more favourable to crystallisation during printing, interlayer bonding improves and the tendency to warp decreases. Where a sufficient chamber temperature is not available, controlled post-print annealing is used to raise crystallinity; however, annealing a part that has already cooled carries a risk of dimensional distortion, especially on large parts. For large PEEK parts, a heated chamber is therefore the decisive element of the process.

Material preparation

Drying: Filament should be dried at the temperature and for the time specified by the material manufacturer and fed from a dry environment during long job cycles.
Bed: The bed is held at a high temperature for first-layer adhesion; a bed surface compatible with PEEK is important.
Nozzle: Carbon-fibre-filled grades (e.g. PEEK-CF) are abrasive and require a wear-resistant nozzle.
Parameters: Nozzle temperature, print speed and cooling depend on the material grade; the manufacturer's data sheet is the starting point.

Design and print orientation for PEEK parts

Radiused corners: Using radii instead of sharp corners reduces stress concentration and corner lifting.
Gradual section changes: Abrupt changes in wall thickness lead to uneven cooling and warping.
Load direction: Interlayer strength is lower than in-layer strength; choose the print orientation so that the main load acts parallel to the layer plane.
Support structures: On dual-extruder systems, support can be printed from a separate head; the support material must be compatible with PEEK processing temperatures.
Machining allowance: Leave a machining allowance on surfaces that need precise fits, bearing seats or threads.

High-performance alternatives to PEEK

Material	Structure	Glass transition (approx.)	Key property	Typical use
PEEK	Semi-crystalline	143 °C	High-temperature performance, chemical resistance	Metal replacement, energy, medical, aerospace
PEKK	Semi-crystalline, slow-crystallising	160 °C	High strength, wider process window than PEEK	Aerospace and defence parts
PEI (ULTEM)	Amorphous	186 – 217 °C (by grade)	Heat resistance, flame-smoke-toxicity performance	Aircraft interiors, electrical, tooling and fixtures
PPSU	Amorphous	220 °C	Impact, hydrolysis and sterilisation resistance	Medical instruments, fluid systems
PPS	Semi-crystalline	90 °C	Chemical resistance, inherent flame retardancy	Components in chemical environments, electrical

Values vary by material grade and manufacturer; design should be based on the data sheet of the material actually used. For a general comparison of materials, see the 3D printing materials guide.

Industrial applications

Aerospace and defence: Ducts, brackets, covers and housings; lightweight metal-replacement components.
Energy and chemicals: Seats, flow elements and housings operating at high temperature and in chemical environments.
Medical: Device components and test parts. Medical applications require medical-grade material and compliance with the relevant regulations.
Automotive and motorsport: Under-the-bonnet components, test parts and fixtures operating at high temperature.
Moulds and tooling: Composite moulds cured at high temperature, and fixtures (see tooling, jigs and fixtures).

Safety

When processing high-temperature polymers, ventilation of the print environment, the warnings in the material safety data sheets (SDS) and protection against hot surfaces are essential. Remove parts and handle the bed only after the chamber has cooled.

PEEK printing on the BPT 2010

Nozzle: Up to 450 °C; 0.4 – 1.2 mm nozzle diameter
Chamber: Controlled environment up to 170 °C; above PEEK's glass transition temperature
Bed: PEEK-coated, multi-zone heating, up to 180 °C
Build volume: 2000 × 1000 × 1000 mm (2 m³)
Extruder: Independent dual extruder, 5 kg per head; model and support from separate heads
Fibre-filled: Materials such as PEEK-CF, with a wear-resistant nozzle
Continuity: Filament sensor; resumes where it stopped after a power cut

Besides PEEK, the BPT 2010 also processes PEKK, PPS, PPSU and ULTEM / PEI. Suitability and process parameters for a specific material grade are verified together through a sample print.

Request a PEEK sample BPT 2010 specifications

Frequently asked questions about PEEK 3D printing

What nozzle temperature does PEEK require?

It depends on the grade, but printing usually takes place between 360 and 420 °C. The maximum nozzle temperature of the BPT 2010 is 450 °C.

Why does chamber temperature matter for PEEK?

The chamber determines how quickly the layers cool. A chamber close to or above the glass transition temperature (about 143 °C) supports crystallisation and interlayer bonding and reduces warping. The chamber of the BPT 2010 can be heated up to 170 °C.

Should printed PEEK parts be annealed?

That depends on the target crystallinity and the thermal conditions during printing. Annealing can increase crystallinity, but because it carries a risk of distortion on large parts that have already cooled, the annealing schedule should be planned for the part geometry.

PEEK or ULTEM?

Where the highest continuous service temperature and chemical resistance are needed, PEEK is the choice; where flame-smoke-toxicity requirements come first and an easier process is preferred, ULTEM / PEI grades are considered. The choice follows the operating conditions of the part.

Can carbon-fibre-filled PEEK be printed?

Yes. On the BPT 2010, fibre-filled materials such as PEEK-CF can be printed with a wear-resistant nozzle. Fibre filling increases stiffness, but also makes mechanical behaviour more dependent on print orientation.

Can large PEEK parts be printed in one piece?

The build volume of the BPT 2010 is 2000 × 1000 × 1000 mm. For large PEEK parts, geometry, wall thickness and print orientation should be assessed together; you can request a technical assessment by sharing your part.

PEEK 3D printing: high-temperature polymers.