Material Creep
Dimensional stability of common 3D-printing plastics under load and heat
TL;DR: For functional parts exposed to load and warmth, PC showed the best creep resistance in the cited study, ABS/ASA were usable for moderate conditions, Nylon elongated significantly but didn’t rupture within the test window, and PLA fared worst for creep. Choose materials based on expected load and temperature, not just printability.
What is “creep” and why it matters
Material creep is the tendency of a material to deform gradually under sustained stress, often accelerated by temperature. It’s typically discussed in terms of strain (elongation) over time. For 3D-printed functional parts—hinges, clips, fixtures, brackets—creep shows up as parts that “relax,” sag, or drift out of tolerance under a constant load or in a warm environment.
The study (in plain English)
A recent paper by Oguz Doğan et al. examined creep behaviour of common FFF materials (PLA, ABS, ASA/TPLA/CPE/Nylon/PC) under different loads and temperatures, using ASTM D2990-17 procedures for specimen prep and measurement. The headline trends:
- Higher load and/or higher temperature increased elongation (strain) for all tested plastics.
- Load was generally a stronger driver of elongation than temperature.
- PLA had the poorest creep resistance → best reserved for room-temp, lightly loaded applications.
- ABS/ASA were reasonable choices for moderate loads/temperatures, but not for severe conditions.
- Nylon elongated substantially with load/heat yet did not rupture under the test conditions.
- PC showed the highest resistance to creep among those tested → suitable for higher loads/temperatures.
| Material (FFF) | Relative creep resistance (study summary) | Typical use guidance |
|---|---|---|
| PLA | Low | Models, jigs away from heat, light duty |
| ABS / ASA | Medium | Moderate load, moderate temp; ASA for outdoor UV |
| Nylon | Medium–low (high elongation, no rupture) | Tough parts where some drift is acceptable |
| PC | High | Functional parts in warm/service-load environments |
Design implications & recommendations
- Match material to service conditions: choose PC (or PC-blend) for warm, loaded parts; ABS/ASA for general fixtures; keep PLA for display or low-load room-temp parts.
- Reduce sustained stress: shorten unsupported spans, use ribs/fillets, and spread load over larger contact area (lower stress = less creep).
- Mind temperature: keep functional parts away from heat sources; enclosures can trap warmth and accelerate creep.
- Orient for strength: align layer lines with the principal load where possible to reduce through-layer deformation.
- Test a coupon: for critical uses, print a small test bar and hang a representative load for 24–72 h; measure drift before committing.
Applying this in real projects
Understanding creep helps you choose the right material and geometry before you print. At Ryan Dynamics, we apply these findings when producing functional parts in ASA, ABS, and PC — balancing strength, temperature resistance, and dimensional accuracy. If you need help selecting materials or designing around creep, our Design and Drafting service can refine your model for stability and fit, or get in touch.
Source
Full text (open access): Strojniški vestnik – Journal of Mechanical Engineering.
FAQ
Which filament resists creep best?
In the cited study, PC showed the highest resistance to creep
under load and temperature.
Is PLA good for functional parts in warm environments?
PLA exhibited poor creep resistance; keep
it for light-load, room-temperature uses.
Does Nylon fail under creep?
Nylon elongated significantly but did not rupture within the test
window—it can drift dimensionally under sustained load/heat.