Most 3D printed parts are made from one of four plastics: PLA, PETG, ASA and TPU. Picking the right one is the difference between a part that lasts for years and one that warps on the first hot day. Here's what each is good at, where it falls short, and a quick way to choose.
The quick answer
| Material | Best for | Heat | Outdoors | Flex |
|---|---|---|---|---|
| PLA | Models, prototypes, signs, gifts, indoor parts | Low | No | Stiff |
| PETG | Functional parts, clips, brackets, containers | Medium | Some | Slight |
| ASA | Car parts, outdoor fixtures, anything in the sun | High | Yes | Slight |
| TPU | Gaskets, bumpers, grips, cases | Medium | Yes | Rubbery |
PLA: the detail king
PLA is the most common 3D printing plastic. It prints crisp details, comes in nearly every color, and is great for anything that mostly needs to look right.
Good for: display models, prototypes for shape and fit, name signs, ornaments, cosplay pieces and indoor covers.
Watch out for: heat. PLA starts to soften at around 55 to 60°C (130 to 140°F). That's easily reached on a car dashboard or in a sunny window. It's also stiff, so thin parts can snap instead of bending.
PETG: the everyday workhorse
PETG is a close cousin of the plastic used in water bottles. It's tougher than PLA, bends a little before it breaks, and handles more heat.
Good for: functional parts like clips, brackets, mounts, latches, enclosures and containers. It's our default for most replacement parts.
Watch out for: fine detail and glossy surfaces are a little less crisp than PLA. It's fine in shade outdoors, but long-term direct sun is better handled by ASA.
ASA: built for the outdoors
ASA is similar to ABS, the plastic many factory parts are molded from, but it's made to resist UV light. It holds its shape at higher temperatures and doesn't turn brittle and chalky in the sun.
Good for: car interior and exterior trim, outdoor mounts and enclosures, garden and pool parts, and anything near heat.
Watch out for: it's harder to print well, so it can cost a bit more. For indoor parts, PETG is usually the better value.
TPU: the flexible one
TPU is rubber-like. It squishes, stretches and springs back, and it's very hard to wear out.
Good for: bumpers, feet, gaskets, seals, grips, cable strain reliefs, phone cases and protective covers.
Watch out for: it's not for anything that needs to hold its shape under load. Use it where flexing is the point.
How to choose in 3 questions
- Will it get hot or sit in the sun? If yes, choose ASA.
- Does it need to bend or be soft? If yes, choose TPU.
- Does it carry a load, clip in place or get handled a lot? If yes, choose PETG. If not, and looks matter most, choose PLA.
It's not just the plastic
How a part is printed matters almost as much as what it's printed in. 3D printed parts are built in layers, and they're strongest along the layers and weakest between them. Orienting the part so loads run along the layers, adding more solid walls, and increasing the fill inside can make the same plastic dramatically stronger.
That's why it helps to tell the printer what a part does and where it goes, not just what it looks like.
What about food, chemicals and high heat?
For parts that touch food, sit in strong chemicals, or get close to engines and heating elements, ask before you print. Those jobs may need a specialty material, a coating, or a different manufacturing method entirely.
Bottom line
PLA for looks, PETG for everyday function, ASA for heat and sun, TPU for flex. When in doubt, describe the job and let the shop choose. At Print Pros 3D, every quote includes a material recommendation. Get a free quote.