“Strongest filament” depends on what kind of strength you need. A part that has to hold a heavy load, survive a drop, flex without snapping, or keep its shape near a hot motor each needs something different. Here’s how the common options compare, and how to choose.
First: what does “strong” mean?
- Tensile strength: how much pulling force the material takes before it breaks.
- Stiffness (Young’s modulus): how much it resists bending. Stiff parts hold their shape under load.
- Toughness / impact resistance: how much energy it absorbs before cracking, for example in a drop or a knock.
- Layer adhesion (Z-strength): how well the layers bond together. This is usually where FDM prints actually fail.
- Heat resistance: whether it keeps its strength when warm.
How the common filaments compare
These are general characteristics. Exact figures vary a lot by brand and print settings.
| Filament | Strength | Stiffness | Toughness | Ease of printing | Notes |
|---|---|---|---|---|---|
| PLA | Good | High | Low (brittle) | Very easy | Softens around 55–60°C |
| PLA+ / tough PLA | Good | Medium–high | Better than PLA | Very easy | Additives improve impact resistance |
| PETG | Good | Medium | Good | Easy | Bit stringy, more heat resistant than PLA |
| ABS / ASA | Moderate | Medium | Good | Harder (needs an enclosure) | Heat resistant, fumes |
| Nylon | High | Low–medium | Excellent | Hard (absorbs moisture) | Very tough, flexible |
| Polycarbonate | High | Medium | Excellent | Hard (high temperatures) | One of the strongest, but demanding |
| Carbon fibre-filled | Good | Very high | Often lower | Medium | Abrasive, needs a hardened nozzle |
| Graphene-enhanced PLA | Higher than PLA | Higher than PLA | Better Z-strength | Very easy | No special nozzle, adds thermal conductivity |
So which is strongest?
- For the absolute strongest parts, polycarbonate and nylon (often fibre-filled) top the charts. They also need high temperatures, enclosures and dry storage, and can be tricky to print.
- For stiffness, carbon fibre-filled filaments are excellent, but they’re abrasive and can wear brass nozzles quickly.
- For the best strength you can get with PLA-level ease, graphene-enhanced PLA is hard to beat.
Why graphene PLA is the practical choice for most people
Most people want stronger parts without changing their printer setup, buying a hardened nozzle or fighting with warping. That’s where Graphene SuperTough PLA fits. Compared with standard PLA it offers:
- 25% higher tensile strength
- 35% higher stiffness (Young’s modulus)
- 45% higher strain to failure in the Z-direction, which strengthens the weak point of most prints
- 3x thermal conductivity
- The same print settings as PLA: standard nozzle, no enclosure
Full figures are on the data sheet. Wondering how it compares with carbon fibre? Read Graphene vs Carbon Fibre Filament.
5 tips to make any print stronger
- Orient the part so the load runs along the layers, not across them.
- Add walls (perimeters) before you add infill. Three or four walls often helps more than extra infill.
- Print a little hotter within the recommended range to improve layer bonding.
- Reduce cooling slightly on functional parts. Too much fan can weaken layer adhesion.
- Keep filament dry. Moist filament prints weaker parts.
Buy strong 3D printing filament in the UK
SuperTough PLA 1.75mm · SuperTough PLA 2.85mm
UK stock, dispatched within 24 working hours.
FAQ
Is PLA strong enough for functional parts?
For light-duty parts, often yes. It’s stiff but brittle, and it softens at low temperatures. Graphene-enhanced PLA improves strength and Z-axis toughness while printing just as easily.
Is PETG stronger than PLA?
PETG is tougher and more heat resistant, but PLA is usually stiffer and can have similar or higher tensile strength. It depends on the job.
What’s the strongest filament for a Bambu Lab or Prusa?
Both can print engineering materials. For strong parts with no hardware changes, a graphene-enhanced PLA in 1.75mm is the simplest upgrade.