Material choice is the most important decision in the 3D printing process – and at the same time the one most often made incorrectly. PLA is cheap and easy to print. But a PLA part in an engine bay, in the sun, or under continuous mechanical load is a part with an expiration date.
This article shows which material is designed for which requirement – and where the limits lie.
Material Classes at a Glance
PLA – For Prototypes and Display Models
PLA (polylactide) is the most-printed material worldwide. It’s easy to process, affordable and produces good surfaces.
Heat deflection: ~55–60 °C (Vicat A). A PLA part in a vehicle interior in summer is a risk.
Use: display models, assembly prototypes without load application, brackets in climate-controlled interiors.
Not suitable for: UV exposure, temperatures above 50 °C, continuous mechanical load, contact with oils.
PETG-HF – The Reliable All-Rounder
PETG-HF is the material most often underestimated in technical practice. It’s not “better PLA” – it’s a standalone technical material.
Heat deflection: ~75–80 °C (Vicat B) Tensile strength: ~50 MPa Chemical resistance: good against oils, greases, dilute acids and bases
Use: machine parts, jigs & fixtures, mechanical engineering brackets, fixtures, indoor fluid-carrying parts.
Not suitable for: outdoor use with UV exposure (yellows), temperatures above 75 °C.
ASA – Outdoor Use Without Compromise
ASA (acrylonitrile styrene acrylate) is the standard material for anything used permanently outdoors.
Heat deflection: ~95–100 °C (Vicat B) UV resistance: excellent – no yellowing, no embrittlement Impact resistance: good, even at low temperatures
Use: outdoor housings, automotive add-on parts, façade brackets, signage, anything with direct sun exposure.
Not suitable for: parts with very high continuous mechanical loads (here PETG-HF or PA is better).
PA (Nylon) – High Performance Under Load
Polyamide (PA, nylon) is the preferred material for mechanically highly stressed parts. High toughness, good sliding and abrasion resistance, resistance to fuels and lubricants.
Heat deflection: ~80–110 °C depending on type Tensile strength: ~50–70 MPa Water absorption: PA absorbs moisture – this affects dimensional accuracy and must be considered during storage
Use: gears, bearings, slide guides, impact-loaded housings, structural parts.
Not suitable for: moisture-sensitive precision applications without surface protection.
PA-CF – Carbon-Fiber-Reinforced Nylon for Extreme Requirements
PA-CF combines the toughness of polyamide with the stiffness of carbon fibers. The result: the stiffest and strongest material achievable in FDM printing for plastic parts.
Tensile strength: up to ~100 MPa (XY direction) Stiffness: significantly higher than unreinforced PA Heat deflection: ~110–120 °C Weight: light despite high strength – cheaper than aluminum at comparable stiffness in many applications
Special note: PA-CF requires a steel nozzle – the material is highly abrasive. Correct printing isn’t possible without the corresponding machine setup.
Use: structural parts under high static load, robotics applications, automotive and mechanical engineering prototypes, parts intended to replace aluminum.
Comparison Matrix
| Property | PLA | PETG-HF | ASA | PA | PA-CF |
|---|---|---|---|---|---|
| Heat deflection (°C) | 55–60 | 75–80 | 95–100 | 80–110 | 110–120 |
| Tensile strength | Medium | Medium | Medium | High | Very high |
| UV resistance | No | No | Very good | Medium | Medium |
| Chemicals | Poor | Good | Good | Very good | Very good |
| Printability | Easy | Easy | Medium | Demanding | Expert |
| Cost | Low | Medium | Medium | High | Very high |
Practical Examples: The Right Material for the Case
Orthopedic aids / medical device prototypes: No PLA. Body heat (~37 °C), contact with disinfectants and occasional sterilization require at least ASA or PA. PLA would soften or stain.
Gearbox housing in the engine bay: Temperatures of 80–120 °C, contact with oil and fuel, mechanical vibration – this is PA-CF territory. PETG would soften at the first summer heat.
Bracket for outdoor camera / sensor: UV, rain, temperature swings from –20 to +70 °C → ASA. PETG would yellow and become brittle after one season.
Jigs & fixtures in manufacturing: PETG-HF. Dimensionally accurate, chemical-resistant, reprintable – and cheaper than PA when no extreme temperatures occur.
Structural part in robotics: PA-CF. The weight of an aluminum solution with nearly the same stiffness at a fraction of the manufacturing time.
What We Recommend
Tell us in your inquiry:
- Operating environment (indoor/outdoor, temperature, media)
- Load type (static, dynamic, impact, continuous)
- Quantity and whether reprints are planned
We then recommend the economically sensible material – not the most expensive one. Sometimes PETG-HF is enough where others would sell you PA-CF.