PEEK

PEEK (polyetheretherketone) is a high-temperature superpolymer and one of the strongest, most resistant materials in 3D printing. It holds a continuous service temperature around 250 °C, shrugs off aggressive chemicals and wear, is biocompatible, and rivals metal in performance at a fraction of the weight. This is a professional-grade material for aerospace, medical, and oil & gas, and it can only be printed on a dedicated high-temperature printer with a heated chamber.

What it is good for

• Aerospace and critical load-bearing parts operating at high temperature
• Medical: implants, surgical instruments and fixtures (PEEK is biocompatible and sterilizable)
• Oil & gas and chemical processing: parts in contact with aggressive media and under pressure
• Wear-resistant components: bushings, gears, guides — high abrasion resistance
• Metal replacement where lower weight matters without sacrificing strength

Where NOT to use it

• Hobby pieces, decor and prototypes — the material is expensive and overkill for these
• Printing on a regular printer without a heated chamber — the part will warp, delaminate and never reach full strength
• Items left in direct sunlight long-term — unprotected PEEK is sensitive to UV
• Jobs where ABS, PC or PA are enough — there is no point paying for PEEK

How to print

• Nozzle temperature: 380–430 °C; requires an all-metal hotend with a 450 °C heater and thermocouple
• Bed temperature: 120–160 °C, on PEI or a dedicated adhesion primer
• Enclosure and chamber: an actively heated chamber of 90 °C or higher is mandatory — without it the part warps, delaminates and crystallizes poorly
• Cooling: off or minimal — rapid cooling ruins layer adhesion and crystallinity
• Speed: moderate, 20–40 mm/s — rushing weakens layer fusion
• Adhesion: hot bed + PEI/primer; use a brim for large parts to fight corner lift
• Retraction: moderate, like other engineering plastics; keep the nozzle clean at these high temperatures

Drying and storage

PEEK is hygroscopic, and drying is critical. Moisture during printing causes hydrolysis — water breaks the polymer chains at high temperatures and strength drops irreversibly, which no post-processing can fix. A regular 50–70 °C filament dryer is useless for PEEK — you need a high-temperature oven.

• Drying: 120 °C for 4–5 hours or 150 °C for 3 hours in a high-temperature oven or dryer
• Storage: airtight box with silica gel; print right after drying
• Signs of moisture: bubbles and voids in the extrusion, steam and crackling while printing, porous surface and weak layers

Pros and cons

• Very high strength and stiffness, close to metal at a lower weight
• Service temperature around 250 °C, withstands brief exposure above 300 °C
• High chemical and wear resistance, holds up in aggressive media
• Biocompatible and sterilizable — suitable for medical use

• Needs an expensive high-temperature printer with a heated chamber
• The material itself is costly — one of the most expensive filaments
• Hard to print: warping, delamination, sensitivity to the crystallization profile
• High-temperature drying is essential, otherwise strength drops irreversibly