Polyetheretherketone (PEEK)

PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. The processing conditions used to mold PEEK can influence the crystallinity and hence the mechanical properties. 

PEEK melts at a relatively high temperature (343 °C / 649.4 °F) compared to most other thermoplastics. In the range of its melting temperature it can be processed using injection moulding or extrusion methods. It is technically feasible to process granular PEEK into filament form and 3D printing parts from the filament material using fused deposition modeling – FDM (or fused filament fabrication – FFF) technology.

PEEK filaments have been demonstrated for producing medical devices up to class IIa. With this new filament, it is possible to use the FFF method for different medical applications like dentures.

In its solid state PEEK is readily machinable, for example, by (CNC) milling machines and is commonly used to produce high-quality plastic parts that are thermostable and both electrically and thermally insulating. Filled grades of PEEK can also be CNC machined, but special care must be taken to properly manage stresses in the material.

PEEK is considered a high-performance polymer, that is to say, its high price restricts its use to the most demanding applications only.