Fused deposition modeling (FDM) is a method of 3D printing that uses extruders. In FDM 3D printing, an extruder feeds, melts, and deposits a thermoplastic filament in a prescribed path to build parts layer-by-layer. 3D printer extruders differ based on the placement of the “cold end” and “hot end.” The cold end is the portion of the extruder where the filament is fed into the system. The hot end is where the filament is melted and then extruded by the nozzle. In some printers, the cold and hot ends are near (direct extruder) while in other printers, the ends can be far separated (Bowden extruder).
There are many different types and brands of 3D printer extruders on the market, including the E3D Hemera, the E3D Titan, and the Bondtech BMG. With so many choices, it can be overwhelming to determine which one is best for your project. When purchasing a 3D printer extruder, consider whether print speed or print accuracy is more important for your application. The placement of the cold and hot ends will have a large impact on those two parameters. This article will review the five best 3D printer extruders on the market today.
1. E3D Hemera (Best Direct Extruder)
The E3D Hemera features a dual-drive, hardened stainless steel drive train. This provides a tremendous boost in grip strength (up to 10 kg of force) on 1.75 mm diameter filaments. This leads to a more constrained filament path since the filament has less of a tendency to bend or buckle while being fed into the hot end of the extruder. Additionally, this enables the printing of highly-flexible filaments. The Hemera costs about $124-140 and has a total weight of 388 g as a direct system (the cold and hot-ends are assembled adjacently) and 327 g as a Bowden system (cold and hot-ends are assembled separately).
2. BIQU H2
The BIQU H2 is a direct extruder that uses 1.75 mm diameter filaments, has a weight of 211 g, and has a gear ratio of 7:1. Extruder can exert up to 7.5 kg of extrusion force, depending on the filament material which enables better print accuracy. It costs $70-$100. Because the BIQU H2 sits right above the print head, the overall print head system is heavier than some of the other extruders and hence, print speeds will be slower.
3. Bondtech BMG (Lightest Extruder)
The Bondtech BMG extruder uses 1.75 mm diameter filaments and has a gear ratio of 3:1. Its gear ratio enables it to feed filaments faster and hence, print parts faster compared to the BIQU H2. Additionally, it has an astounding light weight of only 75 g. It can be used either as a direct or Bowden extruder with a suitable adaptor. Coming in at $80-$100, the Bondtech BMG’s dual drive allows for uninterrupted filament feeding. While Bondtech BMG excels at being able to print parts fast due to its lightweight, its dual drive also enables great print accuracy.
4. Micro Swiss Direct Drive Extruder
The Micro Swiss Direct Drive Extruder is a direct-drive extruder. These types of extruders are different from direct extruders in that a toothed gear to feed filaments is directly mounted onto the driveshaft of a stepper motor. What constitutes a direct extruder typically relates to the placement of the cold and hot ends. This particular extruder costs about $100 and uses 1.75 mm diameter filaments. It requires no modifications to existing 3D-printer systems and can simply be plugged in to be used. Being both a direct and a direct drive, Micro Swiss exerts great grip force on filaments – enabling both fast and accurate prints.
5. E3D Titan (Best Geared Extruder)
The E3D Titan is a geared extruder with a 3:1 gear ratio. Geared extruders use a transmission ratio that reduces the rotational speed of the gears that feed the filament. This results in a steady and more powerful flow of print material as opposed to direct-drive extruders like the Micro Swiss that allow fast material flow but can’t control the consistency of the flow. The Titan can be used with 1.75 mm or 2.85 mm diameter filaments. At about $35-54, this is one of the cheapest and most effective extruders on the market today.
What is 3D Printer Extruder?
A 3D printer extruder is the assembly of parts that feeds and processes filaments for printing. A 3D printer extruder has two main sections: the hot end and the cold end. The cold end of the extruder is where filaments are fed from a spool into the system. A sufficient amount of force must be exerted by the extruder’s gears onto the filament to ensure rigidity in the filament during printing. The hot end of the extruder is where the filaments are melted. In passing from the cold end into the hot end, the filament is fed through a “heat break” (a tube that allows filaments to flow freely into the nozzle) and is encapsulated by the “heat block” where it first encounters heightened temperatures. As the filament passes through the heat break and melts, it is finally extruded out of the nozzle to build parts.
For more information, see our 3D printing guide.
Where is the Extruder on a 3D Printer?
The location of the extruder on a 3D printer depends on the type of extruder: direct or Bowden. In direct extruders, the cold and hot ends are immediately adjacent to each other, and the cold end is mounted on top of the hot end. The cold and hot ends are located directly on top of the print head. In Bowden extruders, there is a noticeable distance between the cold and hot ends. The type of extruder has a large impact on the print accuracy and print speed of a job. Direct extruders are generally more accurate, but slower at printing while Bowden extruders are faster at printing but less accurate.
For more information, see our guide on 3D Printer Parts.
How to Select the Best 3D Printer Extruder
Below is a list of steps you can take to select the best 3D printer extruder for your project:
- Consider whether print speed or print accuracy is more important for your project.
- Determine what type of material will be used for your parts (some extruders are only compatible with certain materials and certain sizes of filaments).
- Consider the size of your part and pick an appropriate extruder (Bowden extruders are better for smaller parts).
- Determine your budget for a 3D printer extruder (direct extruders are typically more expensive).
- Choose a 3D printer extruder that is both easy to use and compatible with your 3D printer.
What are the Types of 3D Printer Extruder?
Table 1 below shows an overview of the two types of 3D printer extruders:
Hot and cold ends are assembled together and mounted onto the print head.
- Short distance between the filament grip point and heat break leads to less filament bending and buckling
- Lower print accuracy compared to Bowden extruders
- Has a wider range of potential filament materials compared to Bowden extruders
Separate hot and cold ends are connected by a PTFE tube through which the filament is fed.
- Reduced weight on the print head allows for faster and more accurate print jobs
- Requires more fine tuning to filament feed speed due to increased distance between hot and cold ends.
- Smaller print heads on Bowden systems can enable larger parts to be printed.
How Many Extruders Can a 3D Printer Have?
While most 3D printers only have a single extruder, there are several dual-extruder and even triple-extruder 3D printers on the market. Additional extruders enable both quicker print times and printing in multiple colors. Multiple extruders (dual, triple, or more) allow automatic switching between filaments. Depending on the system, these multiple extruders can even mix filaments together to create unique colors.
What is the Lifespan of a 3D Printer Extruder?
The lifespan of a 3D printer extruder depends on the filament material used, the frequency of usage, and the quality of the nozzle. Generally, 3D printer extruders can last anywhere between 3-6 months. To ensure maximum life, refer to the extruder’s user manual for proper cleaning and maintenance instructions.
What is the Difference Between Direct and Bowden Extruders?
The difference between direct and Bowden extruders is the placement of the cold and hot ends of the system. In direct extruders, the cold and hot ends are right next to each other. This minimizes the distance between the pinch point of the filament (where it meets the gears of the extruder) and the heated components of the hot end. The short distance reduces the tendency of a filament to bend or buckle as a result of forces experienced during feeding. However, it results in slower print speeds. Bowden extruders, on the other hand, have the cold and hot ends separated. Without a heavy assembly on the print head, 3D printers with Bowden extruders can print much faster than direct extruder printers but will require fine-tuning to minimize the potential movement of the filament.
This article presented the five best 3D printer extruders, explained what they are, and discussed each of their features to consider when purchasing. To learn more about 3D printer extruders, contact a Xometry representative.
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