3D printed carbon fiber is probably the second most sought after additive manufacturing technology after metal. Thanks to the latest developments in the field of additive manufacturing, people have finally realized the reality of being able to print with a variety of elusive materials. However, not all carbon fiber 3D printers are the same-some machines use microscopic chopped fibers to reinforce traditional thermoplastics, while others use continuous fibers laid inside a thermoplastic matrix (usually filled with chopped fibers) to A "skeleton" is created inside the part.
Carbon fiber consists of aligned carbon atom chains and has extremely high tensile strength. They are not particularly useful on their own-their thin and brittle nature makes them easy to break in any practical application. However, when the fibers are grouped and bonded together using an adhesive, the fibers distribute the load smoothly and form a very strong, lightweight composite. These carbon fiber composites come in the form of sheets, tubes, or custom formed features and are used in industries such as aerospace and automotive, where strength to weight ratios are dominant. Generally, a thermosetting resin is used as an adhesive. At present, the carbon fiber 3D printer has been included in the WeChat applet "Global 3D Printing Product Library". You can search for "carbon fiber" to find the global carbon fiber 3D printer.
Recent developments in 3D printing technology have enabled companies to print using carbon fiber, although the bonding materials used are different from standard carbon fiber processes. The resin does not melt and therefore cannot be extruded through a nozzle-to solve this problem, 3D printers replace the resin with an easy-to-print thermoplastic. Although these parts are not as heat-resistant as resin-based carbon fiber composites, they do benefit from the strength of the fibers.
There are currently two carbon fiber printing methods: chopped carbon fiber filled thermoplastics and continuous carbon fiber reinforced materials. Chopped carbon fiber-filled thermoplastics are printed by standard FFF (FDM) printers and consist of thermoplastics (PLA, ABS or nylon). This thermoplastic is reinforced with tiny chopped strands, namely carbon fibers. Continuous carbon fiber manufacturing, on the other hand, is a unique printing process that lays continuous carbon fiber bundles into a standard FFF (FDM) thermoplastic substrate.
Chopped carbon fiber-filled plastic and continuous fiber manufacturing, although they also use carbon fiber, have huge differences. Understanding how each method works and its ideal application will help you make informed decisions about what to do in your additive manufacturing work.
3D printed carbon fiber made of chopped carbon fiber filled thermoplastic. Source: Markforged
Chopped carbon fiber is basically a reinforcement of standard thermoplastics. It allows companies to print generally weaker materials at higher intensity. This material is then mixed with a thermoplastic and the resulting mixture is extruded into a spool for fused filament manufacturing (FFF) technology. For composite materials using the FFF method, the material is a mixture of chopped fibers (usually carbon fibers) and traditional thermoplastics such as nylon, ABS, or polylactic acid. Although the FFF process remains the same, chopped fibers increase the strength and stiffness of the model, and improve dimensional stability, surface finish, and accuracy.
This approach is not always flawless. Some chopped fiber-reinforced filaments emphasize strength by adjusting the supersaturation of the material with the fibers. This can adversely affect the overall quality of the workpiece, thereby reducing surface quality and part accuracy. Prototype and end-use parts can be made from chopped carbon fiber because it provides the strength and appearance required for internal testing or customer-facing parts.
Carbon fiber 3D printing is reinforced with continuous fibers. Source: markforged
Continuous carbon fiber is the real advantage. This is a cost-effective solution that can replace traditional metal parts with 3D printed composite parts because it can achieve similar strength using only a small part of the weight. It can use continuous filament manufacturing (CFF) technology to embed the material in a thermoplastic. Printers using this method lay a continuous high-strength fiber (such as carbon fiber, glass fiber or Kevlar) through a second printing nozzle inside a thermoplastic extruded through FFF during printing. Reinforcement fibers form the "backbone" of the printed part, producing a hard, strong and durable effect.
Continuous carbon fibers not only increase strength, but also provide users with the option to reinforce in areas where higher durability is required. Due to the FFF nature of the core process, you can choose to strengthen it layer by layer. In each layer, there are two methods of reinforcement: concentric shaft reinforcement and isotropic reinforcement. Concentric fills strengthen the outer boundaries of each layer (inside and outside) and extend into the part with a user-defined number of cycles. Isotropic filling forms a unidirectional composite reinforcement on each layer, and carbon fiber weaving can be simulated by changing the direction of reinforcement on the layer. These enhancement strategies enable industries such as aerospace, automotive, and manufacturing to integrate composite materials into their workflows in new ways. Printed parts can be used as tools and fixtures (these require continuous carbon fiber to effectively simulate metal properties), such as tools at the ends of arms, soft jaws, and CMM fixtures.
Today, the field of additive manufacturing has exploded, and some printers offer the capability of carbon fiber printing. However, you'd better pay attention to the composite materials you purchase and the applications for which each fiber is already open. Unless it indicates that it is continuous carbon fiber, this material is almost certainly composed of chopped carbon fiber-reinforced filaments. Although both provide independent value, being able to print both is the best way to meet all your application needs.