Yes, PLA can soften and warp in a hot car. PLA starts to soften around 55 to 60 °C, and a parked car's interior, especially the dashboard, can get hotter than that on a sunny summer day. For car parts, use ASA, which holds up to roughly 95 to 100 °C and resists sunlight.
Heat limits of common printing plastics
| Plastic | Starts to soften around | OK in a hot car? |
|---|---|---|
| PLA | 55 to 60 °C | No |
| PETG | 75 to 80 °C | Inside, out of direct sun, usually |
| ABS | About 100 °C | Yes, but it yellows in sun |
| ASA | 95 to 100 °C | Yes, best choice, UV resistant |
| Nylon (SLS) | Higher still for most grades | Yes |
So how strong are 3D printed parts?
Strong enough for most brackets, clips, knobs, mounts and housings, as long as the part is designed and printed with strength in mind. Three things decide it:
- Material. PETG and ASA bend before they break. PLA is stiff but snaps. TPU flexes.
- Print orientation. FDM parts are weakest between layers. A part that's loaded across its layers can split, so we orient the part so the load runs along the layers.
- Walls and infill. More perimeter walls add more strength than more infill. Functional parts get thicker walls.
When a printed part isn't enough
Anything safety critical, under heavy constant load, or near an engine or exhaust should stay metal. See CNC vs 3D printing.
Need a car interior part? Tell us where it goes and we'll print it in ASA. Describe your part or compare materials.