ABS, ASA and TPU: when PLA and PETG are not enough

PLA and PETG, the materials in the quote calculator, cover most everyday parts. This article is a reference guide so you can recognise when your project needs something else, and so that you can describe it clearly if you write to us. If you think your part needs one of these materials, send us a message with your model and what the part has to do, and we will tell you what we recommend.

For most everyday parts, PLA and PETG are enough. The cases below are the exceptions.

PLA and PETG have limits that show up in a few typical situations:

• Heat. PLA softens around 55 to 60 °C and PETG from about 70 °C. A part near an engine, a heater or a hot lamp needs more.
• Sun and weather over years. Both plastics age outdoors, especially in strong sun.
• Flexibility. Neither makes a soft, rubbery part such as a seal, a bumper or a grip.
• Special demands. Chemical resistance, post-processing or particular regulations can call for another material.

ABS is the plastic behind many everyday objects, from toy bricks to appliance housings. In a 3D print it handles higher temperatures than PETG, typically in the region of 85 to 100 °C before it softens, and it is tough and fairly stiff.

It also brings difficulties. ABS shrinks as it cools, so large flat parts tend to warp unless the printer is enclosed and warm. It gives off a noticeable smell while printing and needs good ventilation. It can be smoothed with acetone vapour, which is a practical advantage for some projects but a hazardous process that should be done with care. In strong sun, ABS can yellow and become brittle over time.

Good for: car interior parts, brackets near heat, housings for electronics, parts that will be smoothed or glued with solvents.

ASA is similar to ABS in strength and heat resistance, and it is designed to hold up better to sunlight and weather. Colours stay stable for longer and the surface ages more slowly than ABS. It prints with the same difficulties as ABS: it warps, it needs warmth around the print and it smells during printing.

Good for: parts on cars, bikes and boats, garden equipment, enclosures and outdoor brackets that sit in the sun for years.

TPU is a flexible, rubber-like plastic. The 95A in the name refers to its hardness on the Shore A scale. At 95A it is firm but still flexible: it bends, compresses and returns to shape. That makes it useful where a rigid plastic would crack or transmit vibration.

TPU prints slowly and the settings are demanding, because the soft filament can stretch and tangle. Fine details and long unsupported bridges are harder. Parts print with a slightly rough look and are not as sharp as PLA.

Good for: seals and gaskets, bumpers, feet for equipment, protective covers, grips, vibration damping and flexible hinges.

Sometimes. Before you move to a harder material, ask whether the design could change:

• If heat is the issue, can the part sit farther from the source, or can a metal part take the hot section?
• If you need a little flexibility, a thin PETG wall can act as a light spring.
• If you need weather resistance, a PETG part in shade can be enough, and a replacement every few years may be acceptable.

If the answer to all of these is no, you probably do need one of the materials above.

A good request makes it faster for everyone. Include the model file or a description, the size, the number of pieces, where and how the part will be used, the highest temperature it will meet, whether it will be outdoors, and whether it has to flex. With that, we can say whether PLA or PETG will do, or whether it needs something else.

We would rather tell you plainly that a material is not suited to a part than print something that fails. No price or promise is made until we have looked at your request.