Application challenges and breakthroughs of carbon fiber reinforced composite materials in 3D printing

Technical routes for carbon fiber reinforcement

There are three main routes for carbon fiber reinforced 3D printing materials: continuous fiber composite wire (CF-CRF), chopped fiber filler wire and metal-based carbon fiber sintering. Among them, CF-CRF technology synchronously extrudes carbon fiber bundles and nylon or PEEK matrix to form a continuous fiber-reinforced structure, and the mechanical properties can be improved by two to three times. The chopped fiber route can be realized using a common FDM printer on the market with a special nozzle. The cost is lower but the enhancement range is between 30 and 50 percent.

Special manifestations of anisotropy

The strength and modulus of carbon fiber-reinforced composite materials in the fiber direction far exceed those in the non-fiber direction, which is in sharp contrast to the isotropy of traditional metal materials. When designing parts, it is necessary to align the fiber direction with the main stress direction. This is achieved by setting the fiber arrangement angle in the slicing software. When loads come from multiple directions, approximately isotropic mechanical behavior can be achieved by alternating fiber layers.

Equipment adaptation and cost challenges

Continuous fiber printing requires a dedicated multi-channel extruder and a high-precision fiber guiding mechanism. The equipment cost is three to five times that of ordinary FDM printers. Carbon fiber abrasives are extremely abrasive to nozzles. Brass nozzles have a service life of only a few hours. It is recommended to use hardened steel or ruby ​​nozzles. The control of fiber arrangement consistency in mass production still requires a process verification cycle as a guarantee.