These are some of the strongest 3D printer filaments for durable parts

When it comes to choosing 3D printer filaments for durable parts, the stronger the filament doesn't always guarantee a stronger print. The type of material can impact how well the part can handle bending, flexing, or rough treatment. Two of the strongest practical materials for filament-based 3D printers accessible to average makers are carbon-fiber-reinforced nylon (PA-CF) and polycarbonate (PC).

Carbon-fiber-reinforced nylon (PA-CF) is created by combining nylon with short carbon fibers. This combination makes the finished material stiffer and more resistant to bending under load. Bambu Lab's dry-state test shows that PA6-CF has a bending strength of 151 megapascals (MPa) and a heat-deflection temperature of 186 degrees Celsius.

This makes it ideal for brackets, fixtures, and other working parts rather than decorative items. However, carbon fibers inside PA-CF are abrasive, so brass nozzles may not last long and require specialized nozzle material and temperature settings for optimal use.

Polycarbonate (PC), on the other hand, is a stiff engineering plastic with good heat resistance, suitable for parts subjected to more than light use. It exhibits tensile strength of 69.1 MPa across printed layers and 52.8 MPa between them. However, PC is more sensitive to temperature and requires specific nozzle and bed temperatures, as well as an enclosed printer to prevent warping. Unlike carbon-fiber composites, PC creates strong parts without chopped fibers.

When comparing PA-CF and PC, the former has a higher bending strength but also comes at a higher price point. A 1kg spool of Polymaker's Fiberon PA6-CF20 costs $52.99, while Polymaker's PolyLite PC is priced at $29.99 for the same quantity. Ultimately, the choice between these two materials depends on the specific requirements of your project, considering factors like strength, flexibility, cost, and the capabilities of your 3D printer.