Polyether ether ketone (PEEK) is an advanced 3D printing filament valued for its high heat resistance, chemical resistance, mechanical strength and low friction properties. PEEK is used to create durable parts for demanding applications in aerospace, automotive, medical and industrial settings. This guide covers everything you need to know about 3D printing with PEEK filament.
What is PEEK Filament?
PEEK is a high-performance thermoplastic polymer belonging to the polyaryletherketone (PAEK) family. The molecular structure of PEEK consists of an aromatic ketone backbone bond and ether linkages. This structure gives PEEK exceptional thermal, chemical and mechanical properties.
Some key properties of PEEK filament include:
- High heat resistance – PEEK has a continuous service temperature of 250°C and can withstand peaks of 310°C. This makes it suitable for applications that experience high heat loads.
- Chemical resistance – PEEK offers excellent resistance to solvents, fuels, acids and bases. It has broad chemical compatibility for harsh environments.
- Mechanical strength – PEEK has a tensile strength exceeding 100 MPa and a flexural strength over 170 MPa. Parts printed in PEEK are rigid and stiff.
- Low friction – PEEK has a low coefficient of friction, allowing smooth motion for moving parts. The polymer is often used as a replacement for metal bearings.
- Radiation resistance – The aromatic structure of PEEK gives it radiation shielding properties useful in nuclear and medical applications.
- Biocompatibility – PEEK is biocompatible and chemically inert, making it suitable for long-term medical implants.
With its well-balanced property profile, PEEK offers an attractive option for engineers looking to 3D print durable and high-performance parts.
Types of PEEK Filament
PEEK filament is available in various formulations to suit different 3D printing needs:
- Unfilled PEEK – This refers to neat PEEK with no additives. It provides optimal thermal and chemical resistance.
- Carbon fiber reinforced PEEK (CFR-PEEK) – The addition of carbon fiber boosts strength and stiffness while retaining dimensional stability.
- Glass fiber reinforced PEEK (GFR-PEEK) – Glass fiber improves tensile strength and reduces warpage. GFR-PEEK offers a more economical alternative to CFR-PEEK.
- Bearing grade PEEK – Optimized for low friction and wear resistance in moving parts. Contains internal lubricants and additives.
- Flame retardant PEEK – Formulated with flame retardants to meet safety standards in electronics and aircraft components.
- Medical grade PEEK – Complies with biocompatibility standards for long-term implants. May contain additives like barium sulfate for radiopacity.
The reinforcement, lubricants and additives blended with PEEK powder tailor the filament properties for specific applications.
Benefits of 3D Printing with PEEK
Here are some of the major benefits offered by PEEK 3D printing:
- Replaces metals – PEEK can replace aluminum, stainless steel and titanium in parts needing high strength, stiffness, hardness and temperature resistance. This allows weight savings.
- Withstands sterilization – PEEK can be sterilized using heat, chemicals and radiation without degradation. This enables uses in surgical tools and implants.
- Biocompatible – PEEK is non-toxic and chemically inert. There is minimal immune system response, allowing it to be used for long-term implants.
- Heat and chemically resistant – PEEK maintains mechanical strength even when exposed to aggressive fuels, acids, bases, and oxidative chemicals. It also handles repeated autoclaving.
- Good wear properties – The smooth surface finish and low friction of PEEK make it suitable for bearings, pistons, cams, rollers and other moving components.
- Electrically insulating – PEEK has high dielectric strength and resistivity. This allows electrical insulation applications.
- Customized properties – PEEK can be blended with reinforcements, additives and fillers for specific requirements. Parts can also be machined after printing.
By leveraging these advantages, PEEK 3D printing enables lightweight, durable and high-performance end-use parts.
Applications of PEEK 3D Printing
The unique property profile of PEEK makes it suitable for 3D printing parts used in:
- Aerospace – Engine components, interior parts, ducts and housings that must withstand high temperatures. PEEK offers an alternative to metals.
- Automotive – Under-the-hood parts exposed to oils, coolants and high heat. Also used for gears, bearings and other wear components.
- Medical – Implants, prosthetics and dental devices that require biocompatibility and sterilization resistance.
- Chemical processing – Valves, pumps, pipes and fittings needing chemical corrosion resistance.
- Oil and gas – Seals, collectors, well heads and downhole parts that experience thermal extremes and chemical exposure.
- Electronics – Insulators, connectors and bobbins that require electrical insulation and heat resistance.
- Food processing – Nozzles, valves, scrapers and parts that handle high temperatures and caustic cleaning solutions.
- Aerospace – Engine components, interior parts, ducts and housings that must withstand high temperatures. PEEK offers an alternative to metals.
With such diverse applications, PEEK 3D printing provides engineers with new design freedom to make durable and tailored parts.
Best Practices for 3D Printing PEEK Filament
To achieve optimal results with PEEK 3D prints, follow these best practices:
- Dry filament – PEEK is hygroscopic and absorbs ambient moisture. Thoroughly dry PEEK filament before printing to prevent nozzle clogs and popping. Use a dehumidifying filament dryer at 80°C for 4-8 hours.
- Preheat the bed – Heat the print bed to 170-180°C to prevent warping due to residual stresses. Use a glass or Garolite bed with polyimide tape or PEEK adhesive spray.
- Print in an enclosure – Drafts and temperature drops can induce warping stresses. Maintain a consistent ambient temperature of 100-180°C in an enclosure.
- Optimize cooling – PEEK solidifies quickly, so use minimal cooling fans. Slow down prints to allow each layer to bond well before depositing the next.
- Use a wear-resistant nozzle – PEEK’s abrasiveness accelerates nozzle wear. Choose a hardened steel or ruby nozzle for extended nozzle life.
- Clean the nozzle -Residues can cause clogs and affect surface finish. Perform atomic pulls and cold pulls routinely to remove accumulated PEEK.
Following these proven methods will help you achieve dimensionally accurate and visually appealing PEEK 3D printed parts. Test different settings to optimize for your specific 3D printer and environment.
Choosing a 3D Printer for PEEK
PEEK printing requires a high-temperature 3D printer capable of maintaining a hot nozzle and bed. Here are the most suitable 3D printer options:
- Industrial extrusion – Commercial printers like the Stratasys Fortus offer high outputs, large beds and process control for PEEK.
- High-temp extrusion – Affordable high-temp 3D printers from INTAMSYS, 3devo and 3DXTECH print PEEK.
- Laser sintering – Selective laser sintering (SLS) uses a powder bed and laser to fuse PEEK powder. Produces isotropic properties.
- Lamination welding – Thermal welding of PEEK laminates allows large, production-grade parts. Used by companies like JuggerBot 3D.
Look for a chamber temperature rating exceeding 180°C and controllers capable of maintaining a precise, stable temperature. Nozzle options from hardened steel or ruby are recommended.
These industrial platforms provide the high-temperature capabilities needed to process PEEK without degradation.
PEEK Filament Cost Considerations
As an advanced engineering material, PEEK 3D printing filament costs more than standard materials like ABS and PLA. Expect to pay $175-600 per kg. Aerospace-grade PEEK certified to stringent quality standards sits at the higher end.
For companies, the return on investment comes from:
- Part consolidation – PEEK can replace assemblies with integrated components.
- Weight reduction – Lighter PEEK parts save on fuel costs in transport.
- Lifecycle savings – PEEK’s durability exceeds other plastics and metals.
- Design freedom – Complex geometries possible with 3D printing.
While PEEK has a higher initial cost, these long term savings often offset that premium. And as material usage goes down with 3D printing, PEEK becomes more economically viable for small batches.
Safety Considerations for PEEK 3D Printing
Although PEEK is considered biologically inert and non-toxic, certain safety precautions should be followed:
- Wear respiratory protection – Use an approved mask or respirator when handling PEEK powder to avoid inhalation. Nanoparticle exposure is a concern with powder-based SLS printing.
- Vent toxic fumes – PEEK degrades into hazardous fumes above 430°C. Ensure print chamber fumes are adequately ventilated.
- Prevent dust explosion – PEEK powder can combust when finely dispersed in air. Take precautions against clouds of polymer dust.
- Wear protective gear – Use gloves, arm sleeves, goggles and a lab coat when handling PEEK powder. Avoid skin contact.
- No food contact – Avoid direct food contact applications due to lack of FDA compliance. Use an inert barrier coating if required.
With responsible safety practices, PEEK 3D printing can be done safely. Refer to the material safety data sheet for complete health and safety information.
The Future of PEEK 3D Printing
As technology improves, PEEK 3D printing is gaining traction for an increasing range of industrial uses. Here are some future trends:
- New extrusion printing methods – Emerging binder jetting and high-precision extrusion techniques will expand PEEK printing capabilities.
- Reinforced composites – Novel fillers like nanotubes and graphene will allow tailored mechanical properties and electrical conductivity.
- Better powder recycling – Improved processes for reusing and consolidating PEEK powder will make SLS more sustainable.
- Hybrid manufacturing – Combining 3D printing, CNC machining and molding will enable complex PEEK parts.
- Aerospace adoption – More aircraft components and engine parts will be 3D printed in PEEK as certification progresses.
- Mass customization – PEEK’s biocompatibility will drive customized medical implants and prosthetics.
As technology catches up with material science, PEEK 3D printing will become faster and more accessible. This will unlock new design spaces and expand PEEK’s applications.
Conclusion
With its high heat resistance, chemical inertia and mechanical performance, PEEK is a polymer uniquely suited to 3D printing sturdy and long-lasting parts. As 3D printing processes continue advancing, PEEK will see broader adoption across aerospace, automotive, medical and industrial sectors. Engineers now have an exciting new option for creating durable and lightweight components able to withstand extreme environments. By adopting PEEK 3D printing with the right techniques, you can build parts that improve lifecycle costs, enable customization and push performance limits.
