PLA, PETG, ABS, ASA: deciding in five questions

Question 1 — does the part live outdoors?

If so, it is settled: ASA. The sun is merciless with printing plastics: PLA turns brittle within months, PETG dulls, ABS yellows. ASA is formulated for it, and the premium over PETG is a few euros a kilo.

The same holds for a part behind exposed glass, an object on a terrace, a bike accessory that sleeps outside, outdoor signage. We regularly refuse to print such parts in PLA, even when the customer insists: they come back broken.

Question 2 — does the part get hot?

Above 55 °C, PLA is out. Above 70 °C, so is PETG. ABS holds to about 90 °C, and beyond that you move to polycarbonate.

Watch for hidden temperatures: car interiors, closed enclosures containing electronics, proximity to a radiator or an oven. In those cases the ambient air temperature says nothing about the part.

Question 3 — does the part take any load?

For ordinary use — a handle that gets pulled, a bracket that carries, a clip that flexes at every fitting — PETG is the right choice. It has a quality PLA lacks: it bends before it breaks. A PLA clip snaps clean at the first load; a PETG clip takes it.

For genuinely mechanical loads, with permanent stress or vibration, you move to PA6-CF. That is another price bracket, and it is rarely justified for an everyday object.

Question 4 — does appearance matter more than anything?

PLA gives the best detail, the widest colour choice and the cleanest surfaces. For a model, a display stand, a decorative object, a figure, it is the one.

It is also the easiest to print, so the cheapest in machine time. When a part lives indoors and takes nothing, there is no reason to pay more.

Question 5 — does the part have to flex?

Then none of the four fits: it is TPU. Seals, dampers, impact protection, non-slip pads. It prints slowly, so it costs more in machine time, but nothing else does the job.

TPU comes in several hardnesses. Tell us whether you want something that squashes like a rubber or something that flexes just a little.

The table, in one line

Outdoors → ASA. Hot → ABS. Under load → PETG. Good-looking and unstressed → PLA. Has to flex → TPU.

And if two answers conflict — a part outdoors that gets hot and takes load — write to us. That is exactly the kind of trade-off where advice earns its keep, and it is included in the quote.

Also worth reading

• Flexible TPU parts – seals, dampers, protections
• PA6-CF technical parts – carbon-fibre-filled nylon
• Spare part copied from your broken one