Polyetheretherketone (PEEK) is a high-performance, engineering thermoplastic characterized by an unusual combination of properties. These properties range from high-temperature performance to mechanical strength and excellent chemical resistance. PEEK 3D printing is likely to be a key driver for the use of AM technologies in mass production.
What are the key characteristics which make PEEK a high-performance plastic? What is it made up of? Here you will be able to explore its key properties and benefits in detail, and learn about popular applications (aerospace, automotive, medical…) and processing conditions for this polymer. In this article, we will analyze the latest developments in PEEK additive manufacturing, including all PEEK-based materials available and the systems that can support them
A peek at PEEK 3D printing
Polyetheretherketone (PEEK) is a semi-crystalline, high-performance engineering thermoplastic. This rigid, opaque (grey) material offers a unique combination of mechanical properties, including resistance to chemicals, wear, fatigue and creep as well as an exceptionally high-temperature resistance of up to 260°C (480°F). The polymer belongs to polyketone family of polymers (PEK, PEEK, PEEKK, PEKK, PEKEKK) and amongst them, PEEK is the most widely used and manufactured in large scale.
There are many producers and compounders of modified PEEK polymers in the word: companies and products include Lehmann & Voss (LUVOCOM), RTP Company (RTP 2200 Series), Victrex (VICTREX, PEEK VICOTE), SABIC (LNP THERMOCOMP, LNP LUBRICOMP, LNP STAT-KON), Solvay (KetaSpire, Solviva Zeniva, Tribocomp) and Evonik (VESTAKEEP). Most of these companies also have made investments and hold significant stakes in the additive manufacturing industry.
The PEEK of extrusion
Thanks to its unique properties, 3D printing PEEK allows for the construction of almost any complex design geometry, which cannot be manufactured using other technologies. Fused deposition modeling – FDM (or fused filament fabrication – FFF) methods are used for 3D Printing with PEEK filaments. PEEK is an excellent candidate for FFF due to its low moisture absorption, among other properties, which is preferable to other common FFF materials, such as Acrylonitrile Butadiene Styrene (ABS). The material typically works best with a nozzle temperature of between 360-400 degrees Celsius and a heated bed of 120 degrees Celsius.
Stratasys, the leading thermoplastic extrusion system manufacturer, does not offer PEEK, however, the company has recently introduced PEKK filament for its industrial grade system under the brand name Antero 800. PEKK (poly ether ketone ketone) is a 3D printed variant similar to PEEK material, operating in much the same way as PEEK. Unlike PEEK, PEKK displays both amorphous and crystalline material properties. This makes PEKK quite interesting. Thanks to its unique mechanical, physical and chemical properties, PEKK lends itself to a broader range of uses than PEEK.
The Stratasys PEKK material for FDM additive manufacturing offers significant advantages for many manufacturers, including lighter-weight parts, reduced inventories, and improved profitability. Its chemical resistance means it can be used for components exposed to hydrocarbons, such as fuels and lubricants, as well as many acids. Additionally, low outgassing allows PEKK to be used in confined spaces and sensitive environments, such as satellites, where materials may not outgas under vacuum. A high operating temperature makes it viable for production of components under the hood or in engine compartments.
As extrusion 3D printing evolved beyond the patented Stratasys FDM process, several new manufacturers of thermoplastic extrusion systems capable of industrial level productivity have taken an early lead on developing PEEK and carbon fiber composite PEEK 3D printing capabilities.
The first was Apium. The company’s innovative work on 3D printer development led to the launch of “HPP 155”, the first-ever FFF 3D printer specially designed for printing PEEK, in November 2015. This accomplishment ushered in perspectives that many never thought possible in mainstream manufacturing. In 2017, Apium, introduced the P series 3D printer, the Apium P 155 and Apium P220. The new systems allow users to process a wide range of high-performance polymers, including PEEK.
Shortly after Apium, Italian industrial 3D printer manufacturer Roboze also upgraded its Roboze One beltless 3D printer to enable 3D printing of materials with melting temperatures up to 400° C. The Roboze One +400 was one of the very first competitively priced systems to specifically target PEEK and it has come a long way since. Recently, Roboze introduced the larger size Argo system – which also specifically targets PEEK and other advanced thermoplastics with its HVP Extruder which can reach temperatures up to 550°C with high viscosity polymers such as Carbon PEEK, PEEK and ULTEM AM9085F. The Argo has a thermostatic, dehumidified and controlled printing environment capable of reaching 180°C, to offset the deformation of thermoplastic materials, particularly for larger size parts.
Shanghai-based INTAMSYS pushed its claim to the PEEK market even a few steps further by launching a 3D printing service with worldwide shipping coverage and releasing the technical data sheets for all selectable materials. The high-performance functional materials available through INTAMSYS 3D Printing Service include PEEK, ULTEMTM 1010, ULTEMTM 9085, and PPSU. Furthermore, users can choose from engineering-grade thermoplastics and composites. Customers can order and build their prints up to 450 x 450 x 600 mm through INTAMSYS 3D printing service using the company’s FUNMAT PRO HT systems.
In early 2020, FossiLabs, LLC, a startup company focused on engineering porous bone-like structures in PEEK, launched the first fused filament fabrication (FFF) 3D printed ‘fully’ porous PEEK bone-like structures within implantable devices. FossiLabs thus makes it possible to 3D print solid or defined porous structures anywhere within the 3D space. Prior to this development, all other product offerings have only had surface porosity or windows within defined layers. The only viable alternative for 3D printing implantable, medical-grade PEEK is via SLS technology (EOS), with significantly higher costs.
FossiLabs developed proprietary hardware and software to make it possible to easily identify solid and controlled bone-like macroporosity regions within existing client models. Primarily for spacers and cages for the spine, desired bone growth areas can be defined, and 3D printed in PEEK. The implants also use increased surface area and hydroxyapatite (HA) nanocoating surfaces to provide unparalleled hydrophilicity and faster osseointegration.
PEEK for the masses
While many were skeptical regarding the possibility for FFF system manufacturers to effectively print PEEK parts without leveraging Stratasys’ patented sealed heated chamber, several materials manufacturers began producing and offering PEEK filaments. As 3D printing has demonstrated, there is often a way around patents, if not for commercial purposes then for internal use. The ability to 3D print PEEK in non-sealed chambers was made possible by advancements in materials science and thorough hardware modifications. For this reason, major plastics manufacturers such as SABIC, Solvay and Victrex have made some significant investments in this area. Smaller companies specializing in 3D printing – such as 3DXTECH in the US, 3D4Makers in the Netherlands and TreeD Filaments in Italy – have either been offering PEEK and composite PEEK filaments to their clients or providing it to the 3D printer manufacturers.
Plastics giant Solvay may be the farthest ahead in PEEK filament development as the company launched two PEEK filaments in 2018. This initiative represented the first step in Solvay’s plan to offer a broader portfolio of specialty polymer filaments and powders designed specifically for high-end AM applications. The two filaments leverage Solvay’s high-performance KetaSpire polyetheretherketone (PEEK) polymer: a neat PEEK product and a 10-percent carbon-fiber-reinforced grade. Both PEEK filaments are designed to allow excellent fusion of printed layers, enable high part density and deliver exceptional part strength – including in the z-axis. In 2019 Solvay announced that it would be working in a close partnership with Roboze (along with Stratasys) to further develop its PEEK and PEKK offer.
Lehmann & Voss (Lehvoss) also introduced the LUVOCOM 3F brand for filaments based on LUVOCOM PEEK. The product line includes two materials: the LUVOCOM 3F PEEK 9581 NT, an unfilled PEEK grade used by Roboze, and the LUVOCOM 3F PEEK 9710 BK, a carbon-fiber reinforced PEEK grade. Lehvoss produces and supplies the pellets while filaments are available from partners and the company is looking to work to meet specific market demands. LEHVOSS is playing a key role in expanding PEEK adoption by developing modified PEEK materials which can be printed without warping and without losing strength even without the Stratasys patented sealed chamber. This approach is opening up the PEEK market to a much wider range of systems.
Victrex, another major polymer material manufacturer is also active as a PEEK supplier. The company acquired Zyex in 2017 in order to offer differentiated VICTREX PEEK-based solutions and open up new markets. Zyex is global manufacturer of PEEK fiber, principally for the aerospace, automotive and industrial markets. Today Victrex PEEK has been used by German filament producer 3Dinx.
Another company offering PEEK filament, based on both Victrex and Lehvoss PEEK materials (as well as other potential suppliers in the future, according to a company spokesperson) is Netherlands based 3D4Makers. The filament manufacturer and supplier offers PEEK Natural, a no-additive PEEK grade commonly used for medical research and some aerospace applications, and PEEKQ, which is modified for improved printability and is used for industrial applications, space, and aviation. In addition to PEEKQ and PEEK natural, 3D4Makers also supplies Carbon Filled and Glass Filled PEEK to select clients and can work with them for specific PEEK – as well as PEKK – requirements.
In the US, filament manufacturer 3DXTECH has been offering high-end filaments for advanced applications for quite some time. Its current line up includes both the CarbonX Carbon Fiber PEEK and Firewire PEEK 3D printing filaments, based on Victrex PEEK materials. Both are competitively priced at around $600 per kilogram spools. 3DXTECH also offers Firewire PEKK and CarbonX Carbon Fiber PEKK filaments, produced using Kepstan PEKK materials from Arkema. In fact, the US company is so set on advanced thermoplastics such as PEEK that it began offering the Funmat HT 3D Printer from INTAMSYS in a special bundle offer with its own PEEK and ULTEM filaments, for $5,250.
A PEEK (and a PEKK) at laser sintering
In terms of total demand, we expect PEEK and PEKK powders—especially those reinforced with carbon for even superior mechanical properties—to become widely used in powder bed fusion for manufacturing of end-use parts.
Leading laser sintering system supplier EOS offers its own certified PEEK material, making it the only current provider of a readily approved advanced thermoplastic powder for its own polymer powder bed fusion technology. An increasing number of third-party options have also been successfully utilized on EOS machines. These include applications and materials from RAUCH, a German CNC service provider that has developed a significant expertise on PEEK 3D printing both by filament extrusion and laser sintering.
Among the larger polymer manufacturers, Evonik has been developing new 3D printing materials for polymer powder bed fusion since at least 2014 and has also been identified in the development of PEEK 3D printing materials for laser sintering. Arkema is also working to develop a range of specific grade of Kepstan PEKK powders, that can be used in laser sintering processes to make parts exhibiting extreme toughness.
Oxford Performance Materials (OPM), a US-based AM service company operating in both the medical and aerospace segments, is one of the leaders in PEKK applications using a modified version of EOS machines and a proprietary process called high-performance additive manufacturing (HPAM). Its OXPEKK products are comprised of OPM’s family of proprietary poly-ether-ketone-ketone (PEKK) formulations. With the commercial launch of OXPEKK Custom Compounds, OPM moved on to address critical unmet needs in key markets including the medical, aerospace, automotive, electronics, energy and semiconductor industries.
In 2019, French advanced polymer materials specialists Dedienne Multiplasturgy Group, became the first firm to add the EOS P 810 machine to produce EOS HT- 23 parts, an EOS powder made from Kepstan PEKK. This is a high-performance polymer supplied by Arkema, and reinforced with carbon fibers. EOS P 810 is the first laser sintering solution for mass production of high-temperature PEKK polymer functional parts.
With a construction volume of 700 x 380 x 380 mm, the new EOS P 810 enables fast and economical production of high-performance techno polymer parts directly from CAD data, without the need for tooling. EOS HT-23 parts can ensure high strength at low weight and withstand temperatures well above 200°C. They can also be metalized to provide electrical continuity or serve as electromagnetic shielding.