【3D Printing Knowledge】Carbon Fiber Filament Starter Guide: The Ultimate Comparison of PLA-CF, PAHT-CF, PET-CF, and PETG-CF
When it comes to 3D printing materials, we typically evaluate them based on their printability and mechanical properties. Printability is a crucial factor, determining if a material is suitable for 3D printing and influencing the final appearance and dimensional accuracy of the printed object. Mechanical properties are often overlooked, but they play a critical role in determining if a material is suitable for a specific application.
If you are printing drones, racing cars, or mechanical parts, the product will require basic mechanical properties such as stiffness (resistance to deformation), strength (resistance to damage), toughness (resistance to impact fracture), and high-temperature resistance (ability not to deform under high temperatures). The mechanical properties of these printing materials are crucial and can largely determine the lifespan of the printed product in specific environments. The better the mechanical properties, the more the product can meet a wider range of demanding application scenarios. Materials with excellent mechanical properties are called high-performance materials.
Due to the limited price and capabilities of 3D printers on the market, high-performance materials have received less attention. The Bambu Lab X1 series offers a better solution, perfectly supporting common high-performance materials. At the same time, Bambu Lab aims to provide multi-dimensional system solutions, including printers, printing materials, and printing parameters, to ensure users can enjoy the unique experience brought by 3D printing.
If you are printing drones, racing cars, or mechanical parts, the product will require basic mechanical properties such as stiffness (resistance to deformation), strength (resistance to damage), toughness (resistance to impact fracture), and high-temperature resistance (ability not to deform under high temperatures). The mechanical properties of these printing materials are crucial and can largely determine the lifespan of the printed product in specific environments. The better the mechanical properties, the more the product can meet a wider range of demanding application scenarios. Materials with excellent mechanical properties are called high-performance materials.
Due to the limited price and capabilities of 3D printers on the market, high-performance materials have received less attention. The Bambu Lab X1 series offers a better solution, perfectly supporting common high-performance materials. At the same time, Bambu Lab aims to provide multi-dimensional system solutions, including printers, printing materials, and printing parameters, to ensure users can enjoy the unique experience brought by 3D printing.
What is Carbon Fiber?
A common solution for producing high-performance materials is to inject fibers into a polymer base. Imagine it like adding rebar to concrete. Without rebar, concrete has poor mechanical properties and is prone to cracking under external forces. After adding high-strength rebar, concrete becomes a structure that can resist external forces. The same principle applies to enhancing the mechanical properties of 3D printing materials through fiber reinforcement, where high-strength fibers are encapsulated within the base material.
Carbon fiber is one of the most popular reinforcing fibers, alongside glass fiber and Kevlar. Carbon fiber is a carbon material with a very fine diameter, possessing excellent mechanical properties such as high stiffness, strength, low weight, chemical corrosion resistance, and high-temperature resistance. These characteristics make it very popular in fields such as aerospace, military, racing, and competitive sports. However, production difficulties and high costs limit its large-scale application.
Imagine if 3D printing materials had some of the mechanical properties of carbon fiber; that would be a game-changer for many industries! Current industry practice involves chopping carbon fiber and extruding it with a 3D printing substrate to create the final 3D printing material.
Composed of a 3D printing substrate and carbon fiber, what are the advantages and disadvantages of this hybrid 3D printing material? Advantages include better mechanical properties (stiffness, strength, etc.), higher temperature resistance, higher dimensional accuracy, and the aesthetic texture of carbon fiber. However, it should be clear that the improvement in these aspects varies completely when carbon fiber is added to different substrates. Some aspects can be greatly improved, while others may see little improvement. This difference is directly related to the substrate itself. Carbon fiber materials with significantly enhanced mechanical properties are called high-performance carbon fiber materials. Otherwise, they are considered entry-level carbon fiber materials.
Composed of a 3D printing substrate and carbon fiber, what are the advantages and disadvantages of this hybrid 3D printing material? Advantages include better mechanical properties (stiffness, strength, etc.), higher temperature resistance, higher dimensional accuracy, and the aesthetic texture of carbon fiber. However, it should be clear that the improvement in these aspects varies completely when carbon fiber is added to different substrates. Some aspects can be greatly improved, while others may see little improvement. This difference is directly related to the substrate itself. Carbon fiber materials with significantly enhanced mechanical properties are called high-performance carbon fiber materials. Otherwise, they are considered entry-level carbon fiber materials.
Disadvantages to Consider
1. High-performance carbon fiber materials place higher demands on the printer. An enclosed printing chamber is required to ensure a higher and more uniform chamber temperature. It also requires a nozzle with a higher printing temperature, and the nozzle material must be made of hardened steel, tungsten carbide, ruby, or other ultra-wear-resistant materials. Furthermore, high-performance carbon fiber materials generally have greater rigidity, meaning they are more difficult to bend during printing and may cause more wear on the print path.
2. Since carbon fibers still retain a certain length (about 0.05-0.2mm) in the material and do not melt at the material's printing temperature, they are more prone to clogging during printing.
Bambu Lab printers currently meet the basic needs for using carbon fiber, overcoming the first disadvantage, which was one of the initial design intentions of Bambu Lab printers. The Bambu Lab X1-Carbon features a fully enclosed printing chamber, a hardened steel nozzle, a nozzle temperature up to 300℃, and a bed temperature of 110℃.
For the second disadvantage, Bambu Lab has optimized printing materials and printing parameters to provide a better printing experience. On one hand, the formulation of Bambu carbon fiber materials has been optimized and improved to reduce the likelihood of clogging during printing.
On the other hand, printing parameters have also been matched and optimized. It is recommended to use lower printing speeds and larger nozzle sizes when printing carbon fiber materials.
Common Carbon Fiber Materials
Until now, carbon fiber 3D printing materials might have been considered materials that can improve appearance and mechanical properties but are not easy to print. However, when carbon fiber is added to substrates like PLA, PETG, and PA, the degree of improvement varies. Based on their characteristics and performance, Bambu Lab has different classifications, mainly dividing them into high-performance and entry-level carbon fiber materials. Let Bambu Lab start with two high-performance carbon fiber materials.
- High-Performance Carbon Fiber Materials -
PA-CF
PA-CF is a nylon-based carbon fiber material. Nylon is one of the most common engineering plastics, possessing good comprehensive mechanical properties. It is widely used in industrial applications such as gears and automotive parts through injection molding. When carbon fiber is added to this material, its mechanical properties are significantly enhanced.
Fortunately, PA-CF is also suitable for 3D printing, and the comprehensive performance of its printed parts far exceeds that of ordinary PLA printed parts, making it one of the most common 3D printing high-performance materials. However, nylon materials have a major drawback - high water absorption, making them very sensitive to moisture during the 3D printing process. When nylon materials absorb water, defects such as stringing and oozing are prone to occur, which can lead to clogging and print failure. Additionally, when nylon printed parts absorb water, their strength and stiffness decrease, but their toughness increases. This disadvantage requires Bambu Lab to adequately dry and store the material in a sealed environment when printing with it.
In fact, there are many types of PA (polyamide) materials, with significant differences in performance. In 3D printing, the most commonly used PA types include PA6, PA12, and some special nylon materials. PA6 has strong mechanical properties, but its main disadvantage is that its water absorption rate (about 3%) is much higher than that of PA12 (about 0.3%). However, under dry conditions, the mechanical properties of PA12 cannot compete with PA6, and there is also a significant cost difference between them. In short, an excellent PA-CF (carbon fiber reinforced polyamide) formulation needs to achieve a comprehensive balance in mechanical properties, water absorption rate, cost, and other aspects.
Bambu Lab has launched a specially formulated PA-CF filament, designed to achieve lower water absorption and higher heat resistance. Bambu Lab has also optimized its stiffness in the design to ensure that it can be smoothly printed through the AMS (Automatic Material System) (Related article: 【3D Printing News】Detailed Explanation of Bambu Lab AMS! The Secret to Multicolor Printing!), making it suitable for printing support materials. Bambu Lab names it Bambu PAHT-CF.
In summary, Bambu PAHT-CF is suitable for AMS, boasts the most comprehensive mechanical properties, low water absorption, and high-temperature resistance. It is a versatile high-performance carbon fiber material that can be used in industrial fixtures, jigs, automotive parts, drone parts, and other fields. It can easily meet various demanding application requirements in daily life.
PET-CF
Bambu Lab aims to introduce a carbon fiber material with higher stiffness than PAHT-CF to meet the needs of users who require extremely high stiffness in certain working conditions, which is Bambu PET-CF.
Bambu PET-CF is mainly composed of PET (Polyethylene Terephthalate) and CF (Carbon Fiber). PET is a crystalline plastic widely used in industries such as plastic bottles and automotive parts. It features high mechanical properties, temperature resistance, chemical resistance, and other characteristics. When carbon fiber is added to PET, its mechanical properties, especially stiffness, can be significantly enhanced. Additionally, PET-CF has a significant advantage over nylon carbon fiber, which is its extremely low water absorption rate (approximately 0.3%), allowing printed parts to maintain almost identical mechanical properties even when exposed to moisture. This makes it suitable for humid environments.
The drawback of PET-CF lies in its relative brittleness and poor interlayer adhesion. To address this issue, Bambu Lab has adjusted the formulation of Bambu PET-CF, with its Z-axis impact strength reaching approximately 4.5 kJ/m² (other PET-CFs on the market typically range from 2-3 kJ/m²). With reasonable printing processes and usage conditions, the deficiencies of this material can also be avoided. For example, when using PET-CF structural components, it is best to avoid applying force in the direction of interlayer adhesion and avoid excessive impact or collision to maximize its advantages and minimize its weaknesses.
In summary, Bambu PET-CF offers higher stiffness, ultra-low water absorption, but has weaker interlayer adhesion and is relatively brittle. Depending on the specific application, you can flexibly choose between these two high-performance materials. If you need a filament for AMS, PAHT-CF is the best choice, as PET-CF is not compatible with AMS. A performance comparison between Bambu PET-CF and Bambu PAHT-CF is shown in the figure below.
PAHT-CF and PET-CF Comparison
- Entry-Level Carbon Fiber Filaments -
In the next section, Bambu Lab will introduce two entry-level carbon fiber materials, Bambu PLA-CF and Bambu PETG-CF, to meet the carbon fiber printing needs of more users. The addition of carbon fiber does not significantly improve the performance of PLA and PETG substrates. However, compared to ordinary PLA and PETG, you can consider the addition of carbon fiber as making them slightly stronger and stiffer, while still being easy to print and aesthetically pleasing. Both PLA-CF and PETG-CF can be used for AMS printing.
PLA-CF
Bambu PLA-CF is a filament with a matte carbon fiber texture, which can greatly enhance the aesthetic appearance of products while maintaining printing performance comparable to PLA. To further optimize its printing experience, Bambu Lab has reduced the carbon fiber content to ensure no clogging risk even at higher printing speeds. Although the carbon fiber content is not as high as in high-performance carbon fiber materials, its stiffness still increases by more than 30% compared to ordinary PLA. In addition, carbon fiber can inhibit shrinkage deformation during printing, thereby improving printing accuracy. The disadvantage of PLA-CF is that these carbon fibers may affect the interlayer adhesion strength. But from another perspective, support structures printed with this filament may be easier to remove.
In summary, Bambu PLA-CF has higher stiffness and dimensional accuracy than PLA, features a matte carbon fiber texture, and is easy to print. It is mainly suitable for printing gadgets, functional prototypes, structural components requiring rigidity, and other daily life applications. Its performance compared to ordinary PLA is as follows:
PLA and PLA-CF Comparison
PETG-CF
Another entry-level carbon fiber material is Bambu PETG-CF, which is primarily composed of PETG and CF, featuring a shiny carbon fiber texture. Its mechanical properties cannot reach the level of PET-CF. The key difference in PETG is that "G" stands for glycol. PETG is a glycol-modified version of PET, containing a small amount of glycol as a comonomer. The addition of glycol reduces the crystallinity of PETG, making it more transparent but also reducing its strength and stiffness.
When carbon fiber is added to PETG, it can only slightly improve its strength and stiffness. Compared to PLA-CF, its stiffness is not as high, which means it has better toughness. Additionally, its interlayer adhesion strength is better. In some special cases, the high stiffness of PLA-CF might lead to printing failures, but PETG-CF does not have this risk. In terms of printing experience, it might be slightly superior to PLA-CF. PETG-CF also has good water resistance, UV resistance, and weather resistance, making it potentially more durable when exposed to outdoor elements, less prone to degradation and aging.
In summary, Bambu PETG-CF offers higher toughness, better interlayer adhesion strength, and improved heat resistance. It is suitable for outdoor use, features a shiny carbon fiber texture, and is easy to print. If your prints require better toughness and interlayer adhesion strength, consider using Bambu PETG-CF. If higher stiffness is needed, Bambu PLA-CF is the choice.
PETG, PETG-CF, and PLA-CF Comparison
When people think of carbon fiber materials, they usually associate them with a black appearance. For entry-level carbon fiber materials like PLA-CF and PETG-CF, Bambu Lab offers more color options, making their uses more diverse.
For more detailed parameters, please refer to the Filament Guide and the specific TDS and MSDS documents for each filament.
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