What is Carbon Fiber 3D Printing Filament

What is carbon fiber? Dive into our complete guide to CF 3D printing filament to understand its physical properties, chemical behavior, and manufacturing process. Get started learning everything you need to know about carbon fiber, making it the perfect resource for mastering this versatile material.

What is Carbon Fiber 3D Printing Filament?

Carbon fiber, abbreviated as CF, is a new type of fiber material with a carbon content of more than 95%. It is a high-strength, high-modulus fiber made of organic fibers such as flaky graphite microcrystals aligned along the fiber axis, which become microcrystalline graphite material after carbonization and graphitization treatment.

Carbon Fiber Features

Carbon fiber combines the soft exterior with a rigid interior. It is lighter than aluminum yet stronger than steel, featuring excellent corrosion resistance and high modulus properties. As an essential material in both defense, military, and civilian applications, it not only retains the intrinsic characteristics of carbon materials but also possesses the softness and processability of textile fibers, making it a new generation of reinforcing fiber.

Carbon fiber exhibits numerous superior properties. Its axial strength and modulus are high, with low density and superior specific properties, no creep, and outstanding high-temperature resistance in non-oxidizing environments, good fatigue resistance, thermal conductivity, and electrical conductivity between non-metals and metals. It has a low thermal expansion coefficient with anisotropic properties, excellent corrosion resistance, and good X-ray transmittance. Its electrical conductivity and thermal conductivity are beneficial for electromagnetic shielding.

Compared to traditional glass fiber, carbon fiber’s Young’s modulus is more than three times greater; compared to Kevlar fiber, its modulus is about twice as high. It is insoluble and non-swelling in organic solvents, acids, and alkalis, demonstrating exceptional corrosion resistance.

Carbon Fiber Physical Properties

Carbon fiber is a new material with excellent mechanical properties, characterized by the combined features of carbon materials’ strong tensile strength and the soft, processable nature of fibers. Its tensile strength ranges from 2 to 7 GPa, and the tensile modulus ranges from 200 to 700 GPa. The density is approximately 1.5 to 2.0 grams per cubic centimeter, which is mainly determined by the carbonization temperature. Typically, after graphitization treatment at high temperatures of around 3000°C, the density can reach 2.0 grams per cubic centimeter. Furthermore, its lightweight nature and specific strength, which is 20 times that of steel, make it a material with outstanding physical properties compared to metals such as titanium, steel, and aluminum.

Carbon Fiber Chemical Behavior

Chemically similar to carbon, carbon fiber is inert towards alkalis and can be oxidized by strong oxidizing agents. It begins to oxidize at temperatures above 400°C in the air, producing CO and CO2. Carbon fiber exhibits excellent resistance to corrosion from organic solvents, acids, and alkalis; it does not dissolve or swell, thereby eliminating the issue of rusting. Despite its poor impact resistance and susceptibility to oxidation in strong acids, carbon fiber has positive electrochemical potential, which can lead to metal carburation and electrochemical corrosion when used in combination with aluminum alloys. Therefore, surface treatment is necessary before using carbon fiber. It also has resistance to oil, radiation, and toxic gas absorption, and it can slow down neutrons.

Manufacturing Process

Carbon fiber can be produced from polyacrylonitrile (PAN) fiber, pitch fiber, rayon, or phenolic fiber through carbonization. PAN-based carbon fiber and pitch-based carbon fiber are the most commonly used. The manufacturing process includes fiber spinning, stabilization (pre-oxidation), carbonization, and graphitization, with accompanying chemical changes such as dehydrogenation, cyclization, pre-oxidation, oxidation, and deoxygenation.

High mechanical performance carbon fibers derived from rayon require high-temperature stretching and graphitization, making the process technically challenging and complex. Pitch-based carbon fibers, though derived from abundant raw materials with high carbonization yield, have not seen large-scale development due to the complexity of raw material preparation and lower product performance. PAN-based carbon fibers, capable of achieving high performance, have seen good development in the carbon fiber industry since the 1960s due to their relatively simple production process and excellent mechanical properties.

The production of PAN-based carbon fiber primarily involves the production of the precursor fibers and their subsequent carbonization, including polymerization, degassing, metering, spinning, drawing, washing, oiling, drying, and winding for the precursor production. The carbonization process includes releasing, pre-oxidation, low-temperature carbonization, high-temperature carbonization, surface treatment, sizing, drying, and winding.

Creality Carbon Fiber 3D Printing Filament

Since its establishment in 2014, Creality, a premier brand in consumer 3D printers, has embraced the mission of being a “3D printing evangelist.” Committed to innovating, applying, and popularizing 3D printing technology worldwide.

Know more about details PLA & PLA-CF mechanical properties comparison below:

Performance PLA Hyper PLA-CF
Toughness lmpact Strength -XY 7kJ/m² 4.1kJ/m²
Strength Bending Strength-XY 69MPa 103MPa
Stiffness Bending Modulus -XY 2694 MPa 3552 MPa
Saturated Water Absorption Rate 25C, 55% RH 61.5°C 55°C
Print speed <100mm/s <300mm/s