Manufacturers and hobbyists who use 3D printing processes need to understand the capabilities and limitations of the materials they use. When defining a particular material’s strength, several aspects of strength may come into play.

Types of Strength

Tensile strength is the ability of a substance to resist fracture when it is stretched, like when you pull two ends of it away from each other. Think of the rope in a game of tug of war.

But there are other characteristics that might fall under a maker’s definition of strength. Impact resistance, for example, is the degree to which a material can absorb energy upon impact before breaking, as when struck by an object or force. Meanwhile, chemical or heat resistance is the ability to retain shape and structural integrity when exposed to high temperatures or corrosive substances.

Flexural strength, or more commonly, flexibility, describes how stiff and strong a material is during bending before breaking. Some filaments are made for flexibility, while others create more rigid parts.

A rubber ball has far less tensile strength than a ceramic cup but much greater impact resistance. The cup will shatter if you drop it, whereas the rubber band will just bounce or land unscathed.

Those who use 3D printing devices must be aware of each of these properties and which is the most important for their purpose. Now, let’s look at some of the strongest 3D printing materials.

Polycarbonate

Polycarbonate, or PC for short, has excellent tensile strength and impact resistance. It endures high temperatures, but that means it must be printed at very high temperatures. It creates transparent prints.

Even with the printing challenges it presents, PC is the material of choice for things like safety helmets, transparent protective cases, and even bulletproof shields. This is because of its combination of tensile strength and impact resistance.

ABS

Acrylonitrile butadiene styrene (ABS) is popular for auto parts and home applications. It’s known to be durable, water- and heat-resistant, and able to tolerate mechanical stress. Another benefit of ABS filaments is that, even though they produce a smooth finish, products printed with ABS can be sanded for additional smoothness or painted.

Nylon

Nylon’s tensile strength is lower than polycarbonate. It makes up for this with heat and chemical resistance, impact resistance, and low friction. This makes nylon filament a great choice for moving parts like gears and hinges.

Nylon filament comes in different types that offer varying levels of flexibility. The downside of nylon is that it absorbs moisture easily, so it must be stored carefully to maintain its printability. Like PC, nylon requires high temperatures for printing but produces parts that are heat-resistant. It is prone to warping, but with the right print bed and adhesive, it produces durable parts that stand up to wear.

Composites

Carbon fiber and fiberglass can be added to 3D filament to increase strength without requiring big changes in the printing process. Check to see if the composite filament you are considering uses long or short fibers that are randomly scattered throughout the material. The former will be stronger as they are more likely to align themselves during printing.

The strongest 3D printing materials vary in tensile strength, with polycarbonate at the top of the list. ABS and nylon are impact- and fatigue-resistant with lower tensile strength. When selecting 3D printing filaments, determine the quality that is most important for your final product—do you need something that will be flexible, shatter-resistant, heat tolerant, or low in friction? Your goals for your print will help you determine which filament to use.