Often used to make parts that will be used near ovens, engines, and other hot machinery, these PEI filaments remain strong and rigid in temperatures that would soften most plastic. They’re a lightweight alternative to machined metal parts. Print these filaments on a fused filament fabrication (FFF) 3D printer. Because of their high melting points, 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.

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 part will start to lose structural integrity.