Polypropylene (PP) for 3D printing: durable but hard to print

What makes polypropylene interesting

Polypropylene is one of the most common plastics in the world. It is light, resists most chemicals and, above all, survives thousands of bends without cracking. That is why it is used for hinged lids, hinges, containers, bags and pipes.

In 3D printing it is tempting because it could be used for living hinges and durable lids. Mind that its properties are not what you would expect from TPU: PP is semi-rigid rather than rubbery.

Why it is hard in FDM

• Poor adhesion. PP is slippery and sticks badly to any surface, so it usually needs a special bed or tape.
• Shrinkage and warping. It shrinks a lot as it cools.
• Poor bonding with glue. You practically cannot glue it, and it is held only by welding or a mechanical joint.

Polypropylene and our range

We do not print PP. We offer PLA (€8 per kg) and PETG (€9 per kg), which is only the material share of the price. If you need a part resistant to chemicals or water, PETG is a better choice than PLA, because it resists moisture and many cleaning products. For a living hinge, try PETG at a thickness of a few tenths of a millimetre, but expect it to survive fewer bends than PP.

That suits lids, boxes for components and brackets. It does not suit constant movement and food. Write to jakub.novak@boostello.com describing the use and we will recommend what to choose. We do not promise PP printing.

Example: a lid with a hinge

If you want to print a lid that flexes, design the hinge as a very thin surface and leave enough room around it. In PETG it lasts dozens of openings, not thousands. If you need thousands of bends, you need PP or TPU and a different manufacturer. More under living hinge.

If the part is meant for contact with food, do not treat a 3D print as food safe, as there are tiny gaps between the layers. See food safety.