PEEK and PEI (Ultem) for 3D printing: industrial polymers

What PEEK and PEI are

PEEK (polyether ether ketone) and PEI (polyetherimide, known under the brand Ultem) are among the highest-performing plastics there are. They withstand continuous temperatures above 150 °C, resist chemicals and sterilisation, and have high strength. They are used in aviation, medicine and industry in place of metal.

PEEK is semi-crystalline and resists chemicals better. PEI is amorphous and a little easier to print.

Why you will not find them on ordinary printers

• A nozzle at 370 to 400 °C, a bed at 120 to 160 °C and a heated chamber. An ordinary hotend cannot manage that.
• Shrinkage and warping are large without a controlled temperature environment.
• The filament is many times more expensive than PLA.

So this is industrial printing and not part of the usual range of print services.

PEI as a bed: do not confuse them

PEI turns up on printers in another way too. The surface of most modern build plates is a thin PEI sheet, on which filament sticks well when hot and releases once cool, see PEI build plate. It has nothing to do with printing in PEI.

With us, we print on such a plate with PLA (€8 per kg) and PETG (€9 per kg), which is the material share of the price. We do not print PEEK or PEI. If you need a part for high temperature, write to jakub.novak@boostello.com. The closest alternative we print is PETG, which softens at around 70 to 80 °C, so it is not enough for real heat. We do not promise PEEK printing.

How to tell whether you really need PEEK

Write down your requirements: what maximum temperature the part will see, which chemicals and what load. Many briefs with a figure above 100 °C turn out on analysis to be needlessly strict, because the part never gets that hot. But if the temperature really approaches 150 °C, neither PETG nor PLA will help and you need a specialist manufacturer.

You will find the prices for PLA and PETG in the calculator right after uploading a model. They are worked out from the real grams, print time and the number of pieces on the plate.