PEEK polyetheretherketone is a high-performance thermoplastic with high continuous operating temperatures, strength as well as smoke and toxicity at low flame. Because of this, it is a widely sought-after material by engineers in applications such as under-the-hood automotive parts or aerospace parts. PEEK is viewed by many as a miracle material, not just because it meets many high-tech requirements. PEEK can also be used in the body for implants. Several spinal screws, suture anchors, orthopedic implants, and other long-term body implant products have recently appeared on the market. PEEK is in great demand in areas as diverse as CMF and the spine.
Generally, PEEK implants are made by CNC or, if printed, made with SLS (powder bed fusion, sintering). SLS is a proven technology approved for surgical guides and implants. The high productivity, reliability, and predictability of SLS make it a good technology to make things with, especially when they are small and require precision. However, SLS PEEK powders are expensive. Using SLS, a laser, sinters lose some polymer powders on a bed of spread powder. A new layer is then spread out and the process repeats itself. Unsintered powder is used as a carrier material. Once a large block or cake has been built it is removed from the printer and pieces are sifted out and brushed out to remove the loose powder. This remaining powder can then to a certain extent be mixed with new fresh powder and used again. The recycling rate depends on the powder and processing.
If a printer uses a ton of powder per month, we essentially recycle a third per build, and ultimately throw away half a ton of powder for every 500 kg of components. Nota Bene: This is just a general example to better understand the economics of SLS. With different materials and parts, stains, spaces, etc. you will get different results. This is still much more efficient than, for example, cutting away material for CNC, but is quite a waste. If you’re paying $ 100 a kilo for PA, it’s pretty expensive on a monthly basis. And that’s for a medium-sized machine working at full production. $ 50,000 per machine per month, ouch. Imagine you have ten or more.
But PEEK powder is much more expensive. Depending on the certification, you pay five to nine times more per kilo for PEEK. And it gets worse because the PEEK powder recycling rate in SLS machines is effectively zero. We throw everything away. All of it. Everything that is not a component is thrown away. So depending on the workload, the specific quality and the machine; They throw out a pair of powdered Ferraris per machine per month. Imagine you’re a business owner with your own service bureau and you walk past some 4,911 powder bins every day that you throw away that day, it must hurt.
This explains the reasons for today’s introduction of a PEEK filament for implants by Evonik. 3D4Makers, 3DXtech, Appium and other companies have been offering PEEK filaments for several years. Solvay has a healthcare PEEK filament that you can purchase as well. It conforms to ISO 10993 and is suitable for applications with limited contact for 24 hours and less. The PEEK market leader Victrex has also sold medical PEEK for implantology to a select few. Alternative materials such as PEKK from Arkema are available, but often not with the certifications and approvals for long-term use in the body. Evonik now has an FDM quality that is especially suitable for implants.
Due to the suitability of the material for this purpose and the legal liability, polymer companies are reluctant to allow the use of polymers in the body in the long term. DowCorning, a huge joint venture, went bankrupt over liability for breast implants, which “never made up more than 1 percent of our business,” yet forced the company to raise $ 2.35 billion for applicants. Many polymer companies therefore consider potential revenues from medical implant polymers to be insufficient for a possible headshot for their company.
In this case, Evonik has done its homework on its ASTM F2026-compliant PEEK filament. The business case is clear: with FDM, you only print the material you use (plus any additional support possible). This means that you end up using a lot less material per part than if you were to fill a full SLS machine. Especially with larger implants, FDM has an advantage in terms of time in the machine and time to separation. Besides Kumovis and Vshaper, only a few medical part-specific high-temperature printers have been developed for FDM. I think this can be a fantastically profitable niche that would be difficult to displace a reliable supplier from. The introduction of this FDM material by Evonik can serve as an impetus for the development of high-temperature FDM printers with higher media performance that are required for the use of the filament.
With a surgical implant PEEK material, the VESTAKEEP i4 3DF, 1.75 mm, on 250 or 500 gram spools is based on VESTAKEEP i4 G with good “biocompatibility, biostability, X-ray transparency and easy handling”. X-ray transparency is a great benefit of medical polymer implants as it allows clinicians to verify that the implant is properly placed after implantation and to perform CT scans, especially those with contrast, after or even during implantation or scans they leave appropriate can see the progress of bone or tissue healing. In CTs and MRIs, metal implants cause artifacts on some scans or can prevent surgeons from seeing important details through shadows or opacity. Magnetic implants and MRIs aren’t a great combination either.
Marc Knebel from Evonik Medical Devices & Systems,
“For modern medical technology, the development of our first 3D printable implant material opens up new possibilities for the adaptation of patient treatments. Orthopedics and maxillofacial surgery are examples of areas where this could be applied. Innovative high-performance materials such as Evonik’s VESTAKEEP PEEK, together with highly complex hardware and software and the perfect match between materials and machines, form the basis for a sustainable 3D printing revolution in medical technology. We will therefore gradually expand our product portfolio of 3D printable biomaterials. “
Evonik has released a test grade to make you less shy when you take the plunge for PEEK.
“The term refers to a material class with exactly the same product properties as the implant quality, but without the documentation that is required for approval in medical technology applications. This offers a cost-effective way of adapting the processing properties of the high-performance plastic to a specific 3D printer. “
This is a great idea other companies should look into as it would make research and product development of high performance polymers much cheaper.
