Parts made from these PAEK filaments, a family of materials that includes PEEK and PEKK, remain strong in high temperatures and hold up to wear from repeated use. They don’t degrade when exposed to most chemicals, so they’re often used to print parts for demanding chemical processing applications. Print these filaments on a fused filament fabrication (FFF) 3D printer. Because of their high melting point, you'll need an all-metal extruder and heated printer bed to reach their minimum printing temperature. Without the heated printer bed, parts will cool too quickly and warp.

Fiberglass-filled PEEK filaments make stronger parts that are less likely to warp and shrink than unfilled PEEK filaments. Since they’re abrasive, you should only use them with an abrasion-resistant nozzle.

Tensile strength is the best measure of a filament's overall strength. Similar to the stress applied on a rope during a game of tug-of-war, it's the amount of pulling force a material can handle before breaking. A higher rating means a stronger filament. A tensile strength of 5,000 psi and above is considered good; 12,000 psi and above is excellent.

Maximum exposure temperature is the point at which a printed part will begin to deform. Above this temperature, your printed parts will start to lose structural integrity.

Annealing is the process of heating prints to a specific annealing temperature and then slowly allowing them to cool. This makes the finished print harder, stronger, and better at resisting heat. Maximum temperature after annealing replaces the maximum exposure temperature once this process has been completed.