Polyether Ether Ketone (PEEK) is the strongest 3D filament with a tensile strength of about 7250 PSI. However, it is also very expensive and difficult to print, requiring specialized high-temperature printers and settings. In this article, we will explore the properties, applications, and challenges of PEEK, as well as some alternatives that are more affordable and accessible for 3D printing enthusiasts.
PEEK is a thermoplastic polymer that belongs to the family of polyaryletherketones (PAEKs). It was first synthesized in 1978 by the British company Imperial Chemical Industries (ICI). PEEK has a semi-crystalline structure that gives it exceptional mechanical, thermal, and chemical resistance. It can withstand temperatures up to 250°C and pressures up to 150 MPa. It is also biocompatible, meaning it does not cause adverse reactions when in contact with living tissues. PEEK is widely used in aerospace, automotive, medical, and oil and gas industries, where it can replace metal parts and reduce weight and corrosion.
Why is PEEK the Strongest 3D Filament?
PEEK is the strongest 3D filament because of its high tensile strength, which measures the force required to break a material under tension. According to Clever Creations, PEEK has a tensile strength of about 7250 PSI, which is equivalent to 50 MPa. This is much higher than other common 3D printing materials, such as ABS (4000 PSI), PLA (7500 PSI), or Nylon (7000 PSI). PEEK also has a high modulus of elasticity, which measures the stiffness of a material under stress. PEEK has a modulus of elasticity of about 590,000 PSI, which is comparable to steel (580,000 PSI). This means that PEEK can resist deformation and maintain its shape under load.
How to Print with PEEK?
Printing with PEEK is not easy, as it requires very high temperatures and precise settings. PEEK has a glass transition temperature of about 143°C and a melting temperature of about 343°C. This means that the extruder and the heated bed need to reach these temperatures to print PEEK successfully. However, most consumer-grade 3D printers cannot achieve such high temperatures, and even if they can, they may suffer from thermal degradation and wear. Therefore, printing with PEEK requires specialized high-temperature printers, such as the INTAMSYS FUNMAT PRO 410 or the [Roboze One+400], which can cost tens of thousands of dollars.
In addition to high temperatures, printing with PEEK also requires careful calibration and optimization of other parameters, such as print speed, layer height, cooling, and adhesion. PEEK is prone to warping and cracking due to its high shrinkage rate and low thermal conductivity. Therefore, it is recommended to print PEEK at a low speed (10-50 mm/s), a high layer height (0.2-0.4 mm), and with minimal cooling (0-20%). Moreover, PEEK needs a strong adhesion to the build plate, which can be achieved by using a PEI sheet, a PEEK raft, or a glue stick. PEEK also needs a dry and dust-free environment, as it is sensitive to moisture and contaminants. It is advisable to store PEEK in a sealed container with desiccant and to dry it before printing.
What are the Applications of PEEK in 3D Printing?
Despite its challenges, PEEK offers many advantages and opportunities for 3D printing, especially in high-performance and demanding applications. Some of the most common and promising applications of PEEK in 3D printing are:
Medical implants: PEEK is biocompatible, meaning it does not cause inflammation, infection, or rejection when implanted in the human body. PEEK also has similar mechanical properties to bone, which makes it ideal for orthopedic and dental implants. PEEK can be 3D printed to create custom and complex shapes that fit the patient’s anatomy and needs. For example, [Apium] is a company that specializes in 3D printing PEEK implants for cranio-maxillofacial surgery.
Aerospace components: PEEK is lightweight, strong, and resistant to high temperatures and pressures, which makes it suitable for aerospace applications. PEEK can replace metal parts and reduce fuel consumption and emissions. PEEK can also be 3D printed to create optimized and intricate geometries that are difficult or impossible to manufacture with traditional methods. For example, [Victrex] is a company that produces PEEK filaments and parts for aerospace applications, such as brackets, ducts, and connectors.
Oil and gas equipment: PEEK is resistant to chemicals, abrasion, and corrosion, which makes it ideal for oil and gas applications. PEEK can withstand harsh environments and fluids, such as sour gas, hydrocarbons, and salt water. PEEK can also be 3D printed to create customized and functional parts that can improve performance and reliability. For example, [Solvay] is a company that offers PEEK solutions for oil and gas applications, such as seals, valves, and pipes.
PEEK is the strongest 3D filament, but it is also very expensive and difficult to print. Therefore, it may not be the best option for hobbyists or casual users who want to experiment with 3D printing. Fortunately, there are some alternatives that are more affordable and accessible, but still offer high strength and durability. Some of the most popular alternatives to PEEK are:
Polycarbonate (PC): PC is a thermoplastic polymer that has a high tensile strength of about 9500 PSI and a high modulus of elasticity of about 340,000 PSI. PC also has a high impact resistance and a high thermal resistance, up to 140°C. PC is cheaper and easier to print than PEEK, but it still requires high temperatures (260-300°C) and an enclosure to prevent warping and cracking. PC is widely used in robotics, automotive, and industrial applications.
Nylon: Nylon is a synthetic polymer that has a high tensile strength of about 7000 PSI and a high modulus of elasticity of about 290,000 PSI. Nylon also has a high abrasion resistance and a high flexibility, which makes it suitable for parts that need to withstand wear and tear. Nylon is relatively cheap and easy to print, but it requires moderate temperatures (220-260°C) and a dry environment to prevent moisture absorption and degradation. Nylon is commonly used in gears, bearings, and hinges.
Carbon fiber composites: Carbon fiber composites are materials that combine a base polymer, such as PLA, ABS, or PETG, with carbon fibers, which are thin strands of carbon atoms. Carbon fiber composites have a high tensile strength and a high modulus of elasticity, depending on the percentage and orientation of the carbon fibers. Carbon fiber composites also have a high stiffness and a low weight, which makes them ideal for structural and mechanical applications. Carbon fiber composites are more expensive and harder to print than the base polymers, but they require similar temperatures and settings. Carbon fiber composites are widely used in drones, RC cars, and sports equipment.
PEEK is the strongest 3D filament, but it is also very expensive and difficult to print. PEEK has a high tensile strength, a high modulus of elasticity, and a high resistance to heat, pressure, and chemicals. PEEK is used in high-performance and demanding applications, such as medical implants, aerospace components, and oil and gas equipment. However, PEEK requires specialized high-temperature printers and settings, as well as careful calibration and optimization. Therefore, PEEK may not be the best option for hobbyists or casual users who want to experiment with 3D printing. There are some alternatives that are more affordable and accessible, but still offer high strength and durability, such as PC, Nylon, and carbon fiber composites.
