3D printed carbon fiber is 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.
Explain the role of carbon fiber in 3D printing
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.
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.
At present, the application of 3D printing additive manufacturing technology to carbon fiber reinforced plastics and composite materials (SCFT, LCFRT, CFRP, and CFRTP) has become a rapidly developing digital, intelligent and automated high-tech new technology for the preparation of carbon fiber composite materials at home and abroad. technology. Compared with the traditional carbon fiber composite material forming and preparation process, it has simple process, low processing cost, high raw material utilization rate, green and environmentally friendly production technology, reduces the manufacturing cost of the part, and simultaneously realizes the structural design and manufacturing of composite parts Complete integration, no need to open mold manufacturing, repeated digital mold repair and print parts verification, which can speed up the development cycle, save development costs, and can be an effective technical solution for low-cost rapid prototyping manufacturing. Carbon fiber reinforced plastics and composite materials can be used in aerospace and military industries to use 3D printing technology to produce lighter and stronger industrial-grade lightweight composite materials with complex structural components. The high cost of carbon fiber (CF), the complex preparation process conditions and control, the lack of special processing and molding equipment and the lack of professional engineering and technical personnel make it less developed and applied in the 3D printing industry, but in the future in various industries at home and abroad The application development potential is huge, especially in aerospace, new energy electric vehicle research and development has a broad application prospects and development.
Printing carbon fibers through FDM melt extrusion requires carbon fiber composite materials to be printed with hot-melt plastics. For example, hot-melt plastics such as PETG are used. PETG is a material that has good ductility and can withstand more High CF load while maintaining certain ductility and impact resistance. It adheres well to a variety of construction platforms, and also has excellent layer adhesion. The addition of carbon fibers can also increase its rigidity and dimensional stability. The XT-CF20 printing material of the Dutch colorFabb company contains Eastman PETG material and 20% carbon fiber material. 3DXTECH also uses Eastman PETG material combined with high modulus carbon fiber to make composite materials. Another company, Proto-pasta's carbon fiber reinforcement PLA, is a synthesis of corn starch-derived plastic and carbon fiber composites.
Carbon fiber 3D printing method
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.
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.
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.
Carbon fiber 3D printing technology
Laser sintering technology
Material characteristics: Short fiber reinforced nylon, PEEK, TPU and other powder materials
Process characteristics: Mix chopped carbon fiber and nylon material at a certain ratio, and realize integral molding by laser sintering.
2. Multi-jet melting technology
Material characteristics: Short fiber reinforced nylon, PEEK, TPU and other powder materials
Process characteristics: Through the heating of the lamp tube, under the action of the co-solvent, the cross-section of the part gathers enough heat to achieve melting molding.
3. FDM technology
Material characteristics: filaments reinforced with PLA, nylon, PEEK and other wires
Process characteristics: FDM technology is used to fill long fibers into conventional silk to enhance it.
Carbon fiber 3D printing company
1.Oxford Performance Materials
OXFAB mainly produces carbon fiber reinforced PEEK material, and the applicable 3D printing equipment type is SLS. Currently in the field of aerospace, Oxford Performance Materials (OPM) has been selected to provide 3D printed structural parts for the Boeing CST-100 rocket ship and has begun to ship parts printed with OXFAB materials. In 2016, composites giant Hexcel also completed its strategic investment in the OPM of Oxford Performance Materials.
OXFAB is highly chemical and heat resistant, which is critical for high performance aerospace and industrial components. Extensive mechanical test data proves that OXFAB can be used for 3D printing with complete and ready-to-use parts. OPM is fulfilling some key development contracts with customers in the aerospace and industrial sectors for 3D printed parts for commercial and military aircraft, space, and industrial applications, which can significantly reduce weight and save costs.
Hexcel has multiple factories around the world, producing a series of advanced materials-including carbon fiber, reinforced fabrics, prepregs (or "prepregs"), honeycombs, mold materials, and aircraft structural parts. The integration of OPM with He's investment in the application side is more favorable.
2.Stratasys
Stratasys mainly produces carbon fiber reinforced nylon materials, suitable for 3D printing equipment type FDM. Expert in the field of additive manufacturing technology Stratasys uses nylon 12CF material for FDM 3D printing technology, which contains up to 35% carbon fiber, so it has excellent properties such as a final tensile strength of 76 MPa (MPA). The elongation modulus is 7529 MPa, and the flexural strength is 142 MPa, which is enough to replace metal in many applications and is very suitable for automotive, aerospace and other industries. This carbon fiber reinforced thermoplastic material is used to produce high-performance prototypes. It can withstand the rigorous testing of production parts during the design verification process. It meets the demanding requirements of the production environment and can be applied to fixture manufacturing on the production line.
Stratasys has established a partnership with McLaren. Substantial progress has been made in this partnership, including some 3D printed parts already installed on McLaren's Formula 1.
3.ArevoLabs, Silicon Valley, USA
The company is from the well-known Silicon Valley in the United States. Its main business includes the provision of industrial-grade carbon fiber 3D printers, new carbon fiber and carbon nanotube (CNT) enhanced high-performance materials for 3D printing, and the use of unique 3D printing technology and special A software algorithm that uses existing filament fusion 3D printers on the market to make super-strong polymer parts at the product level. The company launched its first robotic arm 3D printing platform (RAM) in late 2015. The platform is composed of ABBRobotics' commercial 6-axis robot system, FDM3D printing components, terminal effector hardware, and a comprehensive set of software, which can 3D print complex composite parts using high-performance carbon fiber thermoplastics. The RAM is equipped with ABB's smallest robot arm, IRB120, but the scalable software used can match and support larger models. Depending on the model, the minimum construction volume is 1000 cubic millimeters, and the maximum Up to 8000 cubic millimeters. The end-effector hardware includes a thermal management deposition head for processing high-performance carbon fiber-reinforced thermoplastics. Arevo's software suite converts computer-aided design models into a set of instructions to the robot to perform additive manufacturing. The software provides six degrees of freedom and multi-axis tool paths, and the robotic arm has a variable orientation on a three-dimensional surface. An accurate kinematic simulation explains material deposition instructions to verify and optimize the printing process.
4.EnvisionTEC
EnvisionTEC launched the SLCOM1 industrial-grade composite 3D printer in mid-2016 to process carbon fiber fabrics or other varieties of reinforced aramid fiber fabrics. Nylon 6, nylon 11, nylon 12, polyetheretherketone, polyetherketone can be selected. Ketones, polycarbonates, and many other materials are reinforced. Suitable for customization of high-quality 3D printed parts in aerospace, automotive, sporting goods and medical fields. The tailor-made product fully reflects the extraordinary toughness, weather resistance, shock absorption performance, high wear resistance and high strength-to-weight ratio of carbon fiber.
5.Electroimpact
The company's flagship equipment is the automatic fiber placement equipment (AFP). It uses ultra-thin carbon fiber prepreg tape or prepreg automatic laying technology to achieve very fine print quality. The device has a 6.4m robotic arm with 16 head-like devices on the head of the old sewing machine. The entire arm is mounted on a 12m-long track, which can quickly move around the model and print at the same time. Significantly reduce production time and costs for parts and prototypes. The basic principle of AFP is similar to that of conventional FDM printers. It can print parts up to nearly 8m in length, and on uneven and complicated surfaces, the printing speed can reach an amazing 5Om / min. Some well-known institutions and enterprises have purchased AFP equipment and products. For example, NASA's Marshall Aerospace purchased AFP prints as parts for manufacturing spacecraft, and Boeing also purchased multiple Electroimpact AFP equipment. , Hope to be used to make composite material structures on technological wings
6.ImpossibleObjects
The company's patented Composite Materials 3D Printing Process (CBAM) process enables specific materials to be stacked in layers and fused together using a built-in heat source. After printing, you can remove unnecessary materials. ImpossibleObjects uses higher-strength materials for 3D printing technology, such as carbon fiber, Kevlar, and glass fiber. After printing, the parts are 2-10 times stronger than the parts printed with traditional thermoplastic 3D printing. Due to its unique composite material composition, users can also customize it for a variety of applications, including thermal and chemically aggressive environments. Robert Swartz, founder of Impossible Objects, believes that being able to print carbon fiber parts will make 3D printing technology more useful in many areas. At present, the performance of 3D printed plastic parts is not good, and to improve performance, better materials are needed. ImpossibleObjects has developed a new process. The new process avoids printing carbon fiber and starts with carbon fiber cloth. Above the carbon fiber cloth, the printer accurately sprays the cleaning liquid according to the digital instructions, and then adds the resin according to the design; the carbon fiber cloth is stacked and heated to melt the resin and combine with the carbon fiber; finally, the carbon fiber that is not combined with the resin is removed. Impossible0bjects has made equipment available for sale based on the new process. The current business model is to provide customers with printing services for high-strength plastic products. They are commercializing their CBAM technology equipment, and the next step is to sell the equipment directly.
7.MarkForged
The company launched MarkOne, the world's first desktop 3D printer capable of printing composite materials, two years ago. The forming size of this equipment is 305mm × 160mm × 160mm, which can use carbon fiber and other composite materials to directly produce “continuous fiber reinforced” plastic parts that are mechanically comparable to metal parts. This machine has 2 print heads, one will use nylon material, the other will use carbon fiber, glass fiber and other high-strength fiber materials, and then jointly produce super-strong components that can match or even exceed aluminum products. Mark Forged's CEO GregMark believes that an important reason for the high price of carbon fiber is its manufacturing process: complex, time-consuming, and labor-intensive. Mark believes that the new technology developed by his company is as simple as designing the parts in the computer, clicking the button, and the parts come out within a few hours. As the equipment is widely used and practical, the company achieved 400% of revenue in 2015.
8.GermanRepRap
GermanRepRap, headquartered in Munich, Germany, is well known for its high-quality 3D printers and 3D printed wires. As the industry continues to grow, on July 20, 2015, the company announced the launch of a new 3D printed carbon fiber wire, Carbon20. According to the company, this is a wire that can be used for 3D printing functional parts. Carbon20 wire contains 20% carbon fiber, which is also the origin of its name. It is very suitable for 3D printing of industrial parts that need to have reliable rigidity and hardness.
9.Tokyo University of Science
Matsuzaki Ryosuke's team successfully developed a 3D printer capable of 3D printing carbon fiber composite materials. Immerse the filament carbon fiber in a thermoplastic resin to print a three-dimensional shape. Tested with a test piece, its tensile strength is 6 times higher than that of a thermoplastic resin. In the future, the density of carbon fibers will be further increased, and composite materials with higher strength will be printed. The results of the Ministry of Economy, Trade and Industry's strategic basic technology business, which is composed of Super Resin Industry (Inagi City, Tokyo), Nihon University, Tokyo Institute of Technology, and Aerospace Research and Development Agency (JAXA) A 3D print head is made by mixing carbon fiber and a thermoplastic resin, and then the resin is supplied with carbon fiber soaked in the print head. Before printing, carbon fibers need to be heated to make it easier for the resin to penetrate and diffuse between fibers. The extruded resin can be continuously supplied to the carbon fibers for 3D printing. The mixing ratio of fiber and resin can be adjusted according to printing needs.
When the carbon fiber and the thermoplastic resin polylactic acid are used in combination, the occupation rate of the volume fiber is 6.6%, and the tensile strength reaches 200 MPa, which is a 6-fold increase. The modulus of elasticity reached 20 GMPa, a four-fold increase. At this stage, the team has completed the production of the print head and can successfully perform 3D printing. In the future, they aim to increase the carbon fiber density by about 10 times to further improve printing accuracy.
Today, the field of additive manufacturing has exploded, and some printers offer the capability of carbon fiber printing. If the 3D printing industry wants to gain more share of the 100 billion US dollars manufacturing market, 3D printing technology needs to work hard in both equipment technology and materials. The various advantages of carbon fiber reflect the possibility of this goal becoming a reality. To be sure, to compete with traditional manufacturing, composite materials will be one of the driving forces behind 3D printing becoming a mainstream technology.