What Do We Mean by Carbon Fiber 3D Printing?
To be precise, carbon fiber 3D printing typically refers to the use of materials reinforced with chopped carbon fiber.
Less commonly, the term may refer to carbon fiber 3D printing, a process that combines polymer printing with the co-extrusion of continuous fiber strands. In such cases, the carbon fiber is usually laid as a core and encased in another material. This method is significantly more expensive and less widespread, and it often requires modifications to part geometry to accommodate the fiber paths. Carbon fiber-reinforced materials are most commonly used in FDM (Fused Deposition Modeling) technology, but they are also available in SLS (Selective Laser Sintering) processes—typically with carbon-filled polyamide powders.
What Are the Benefits of Carbon Fiber Reinforcement?
Contrary to popular belief, carbon fiber does not significantly increase the material’s overall strength.
Strength is commonly understood as tensile strength — the force required to pull a part apart in relation to its cross-sectional area. Chopped carbon fiber primarily increases stiffness, not tensile strength. In many cases, it also slightly raises the Heat Deflection Temperature (HDT) — the temperature at which the material deforms under load. It’s also important to note that carbon fiber–filled materials are generally abrasive, which can be critical in certain applications. For instance, using a carbon fiber–reinforced gear meshing with a part made from soft metal or plastic may lead to accelerated wear. Finally, one of the most notable advantages of carbon fiber additives lies in surface finish.
One of the main drawbacks of 3D-printed parts is their often rough and layered appearance. The addition of chopped carbon fibers helps to minimize this issue. Prints have a uniform, rough texture with a deep matte finish, which many of our clients find significantly more appealing than parts made from unfilled polymers.
Which Base Polymers Are Most Commonly Blended with Carbon Fiber?
The most commonly used carbon fiber–reinforced material is Nylon CF, with “CF” naturally standing for Carbon Fiber.
This composite offers excellent thermal resistance and high tensile strength. However, base nylon is relatively soft — a drawback effectively mitigated by the addition of chopped carbon fibers. As previously mentioned, this reinforcement also enhances the material’s dimensional stability and stiffness. Depending on the nylon type, heat resistance typically ranges from 140°C to 205°C.
That said, it’s important to keep in mind that nylons are highly hygroscopic — they tend to absorb moisture from the environment. In practice, this moisture absorption can significantly reduce the material’s stiffness when fully saturated.
What Temperatures Can Carbon Fiber–Reinforced Prints Withstand?
Based on our internal testing, copolyesters show the lowest heat resistance among carbon fiber–reinforced materials.
This refers specifically to synthetic polymers such as PCTG and PET-G with carbon fiber additives. These materials begin to soften at around 80°C, which is still higher than their unfilled counterparts. The next group includes nylons. Both carbon fiber–reinforced PA6 and PA12 exhibit heat resistance in the range of 120°C to 155°C, depending on the specific formulation. The highest heat deflection temperatures — among the materials we use in our printing processes — were observed in PPS (Polyphenylene Sulfide). PPS prints are typically used in applications that require continuous operation at temperatures above 200°C. You can read more about the full range of materials we offer on our dedicated materials page.
Other Advantages of Carbon Fiber–Reinforced 3D Printed Parts
In addition to the advantages mentioned above, carbon fiber reinforcement also helps reduce processing shrinkage.
As a result, parts printed with carbon fiber–filled materials are less prone to warping and deformation during the cooling phase. This characteristic also translates into improved dimensional accuracy. That said, it’s important to note that dimensional tolerances in additive manufacturing are generally relatively coarse compared to traditional methods. Most carbon fiber–reinforced filaments should ideally be printed using a actively heated build chamber. Rapid cooling can significantly degrade mechanical properties — especially in the Z-axis, where strength between layers is most critical. To confirm this, we conducted a series of internal tests using PA-CF, a carbon fiber–reinforced PA12-based nylon. Parts printed on a machine with a controlled chamber temperature showed up to 60% better interlayer adhesion compared to those printed without chamber heating.
