What is the Strongest 3D Printer Filament?

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Do you need to 3D print really tough parts? If you want to know which is the strongest 3D printer filament, we’ll show you the top candidates for the toughest 3D printer filaments out there.

3D printers are incredibly useful but in order to get the toughest 3D printed parts possible, not only do you have to configure infill and shells, you also have to make sure you are using the right filament for your end-use.

By using strong filaments, you can make some really tough parts that can withstand lots of use and abuse.

Of course, not all printers can handle all filaments, so we’ll also mention that as we get to each filament.

Before getting into the details of tough filaments, it’s important to understand what we mean by strength.

What makes a “strong” 3D printer filament?

Strength can mean many things. As far as 3D printers go, it’s most common to understand strength to mean tensile strength. This is how much stress the material can come under before it breaks.

Tensile strength is measured in PSI, or pounds per square inch. This is how much force it can withstand before it breaks.

Take these numbers with a grain of salt, though: even though raw tensile strength is a good indicator for filament strength, the strength of your final part will also depend on how it was designed and printed.

The simplest example of this is a hook: when printed flat on the bed, it will be much stronger than if printed standing up. This is because there are far fewer layer lines in a flat print than a standing print.

Strongest 3D printer filaments

Polycarbonate

Polycarbonate is one of the strongest materials that you can 3D print with. Polycarbonate(also known as PC) can be printed with an all-metal hot end as it requires considerably high temperatures. You will also need a 3D printer enclosure to retain heat during the print.

Many folks have done tests on polycarbonate filament. Airwolf 3D were able to hang 685 pounds on a polycarbonate hook, and their tests showed that PC had a tensile strength of 9,800 PSI.

The same part when printed in PLA was only able to withstand half that load.

Thomas Sanlanderer, who is one of the pioneers of 3D printing on Youtube, has also given PC filaments a thumbs up for strength:

How to print polycarbonate

Polycarbonate filament is challenging to print. However, once printed, it is incredibly strong and has great thermal and impact resistance.

You’ll need an all-metal hot end that can handle temperatures up to 300 degrees C. You’ll also need to modify your firmware to allow the printer to raise the temperature of the hot end that far!

Pros

  • Easily the strongest filament out there

Cons

  • Very difficult to print: no fine details or overhangs
  • Requires very high temperatures
  • Limited color choice

Nylon

Nylon comes at a comfortable second place in the strong filaments race. It’s comparatively easier to print, as is much stronger than PLA and ABS.

Tests performed revealed that a clip printed in nylon was able to withstand almost a 500 pound load.

The tensile strength of a nylon hook was around 7,000 PSI. Compare that to the same part in ABS, which could only withstand 4,700 PSI.

Many folks have performed tests on nylon filament and have found similar results:

How to print Nylon

Nylon is more forgiving than polycarbonate, but not quite as much of a breeze as PLA. Nylon must be stored in extremely dry conditions(check out some filament dryers here).

Additionally, you will need an all-metal hot end as you’ll be printing between 250 to 270 degrees C. Some nylon filaments have special chemical compositions that allow them to be printed much cooler at 220 degrees C. If you can get your hands on such a filament, you can use a stock hot end as well.

Pros

  • Very strong and heat-resistant
  • Great for printing parts that come under friction like gears
  • Easier to print than polycarbonate

Cons

  • Highly hygroscopic
  • Prone to warping

Composite filament

The last pick on our list of tough filaments is not one filament, but a family of materials called composites. Composite filaments are mixtures of filaments and additives that alter the properties of the material.

Since there is no one type of composite filament, it’s difficult to compare composite materials to nylon and polycarbonate.

One of the toughest types of composite filaments is carbon-fiber-filled filament. Glass-filled filaments are also very strong.

Tests of these two filaments showed load capacities of 349 pounds for carbon fiber and 268 pounds for glass fiber filaments. Most carbon fiber and glass fiber filaments are composites of nylon, so you can be assured of their strength.

How to print composites

The settings for composite filaments will vary greatly depending on their main material. PLA composites will print much like PLA, and nylon composites will print much like nylon.

Pros

  • Good strength thanks to a combination of multiple materials

Cons

  • Expensive
  • May not print well on stock printers

What about the strength of PLA and ABS?

ABS is an incredibly versatile material and is used almost universally. Everywhere you find plastic, you’ll find some ABS. Computers, cars, and everything in between contains some form of ABS.

Of course, that’s injection-molded ABS rather than 3D printed ABS, but it’s the same material.

ABS is extremely versatile as you can do a lot of post-processing. Prusa Research’s MKS line are all made of ABS, and they have entire print farms that churn out printer after printer.

Interestingly enough, according to Airwolf 3D, when they applied a 285 pound load to a hook made of ABS and a hook made of PLA, the ABS hook snapped(ABS has less PSI tolerance than PLA)!

1:1, ABS is weaker than PLA. However, when designed correctly and with the right reinforcements, ABS is much more reliable for strength than PLA.

How to make PLA stronger

You can greatly increase the strength of your PLA parts through a process called annealing. This involves gradually heating your PLA parts to about 70-80 degrees C. At this point, you’ve hit the glass transition temperature, where the molecules are in flow again. When the part cools again, they will form a stronger bond with one another.

The only disadvantage of annealing is that it slightly alters the shape and dimensions of your parts.

Conclusion

The strongest 3D printer filament is polycarbonate, followed by nylon. For really tough prints, these are the filaments that you should be using. However, they are quite challenging to print, so you’ll need to upgrade your printer with an all-metal hot end and an enclosure to get successful prints.

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