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As these are the two most commonly used extruder systems in FDM printers, I would like to know what is the difference between them. What are the advantages and disadvantages of using each of them?

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A Bowden extruder and a direct drive extruder are two different types of extruder systems used in FDM 3D printers. Both feed filament into the hotend, but differ in the way the filament is pushed into it. The main difference is the location of the extruder motor relative to the hotend, which results in some pros and cons in the usage of both of them.



Bowden extruder

A Bowden extruder has the motor located remotely from the hotend, usually on the printer's frame. Filament is fed from the motor to the hotend through a Bowden tube. This setup is typically used in 3D printers that require high speeds and accelerations, as the reduced weight of the hotend allows for faster and more accurate movement.

Visualization of the Bowden extruder system

The main advantage of a Bowden extruder is that it reduces the weight of the printhead. It can improve print speed and accuracy, especially for faster print speeds. It also reduces the amount of space required in the printhead, allowing for larger hotends or additional features to be added.

However, Bowden extruders can suffer from problems with filament control, such as oozing or stringing of the filament. The friction in the Bowden tube and distance between the extruder and the hotend causes the reaction time of each motor movement to be extended.



Direct drive extruder

A direct drive extruder has the motor located directly above or beside the hotend, which eliminates the need for a Bowden tube. The Bowden tube is typically very short or totally absent. This setup is used in printers that require precise filament control and are capable of printing with a wide range of materials.

Visualization of the direct drive extruder system

The main advantage of a direct drive extruder system is that it minimizes the distance between the extruder and the hotend. It allows for better control of the filament and reduces friction due to a shorter distance between the extruder and the hotend. This allows to use smaller values of retraction settings, which can reduce stringing and oozing. It results in better control of demanding filaments. Direct drive extruders can handle flexible and soft filaments more effectively.

However, the added weight of the extruder motor can result in slower printing speeds and reduced accuracy during high-speed printing. A heavier printhead can also cause artifacts and ringing on the surface of the prints.



In summary, Bowden extruders are better suited for high-speed printing and have a lower risk of filament contamination, while Direct Drive extruders are better suited for more precise printing and more demanding materials. The choice between these two systems ultimately depends on the specific requirements of the printer and the printing application. Costs also have to be taken into account, because direct drive extruders are relatively more expensive than Bowden extruders.

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    $\begingroup$ Nice Q and A for the knowledge base! I added the tag to the question. Maybe you can add some words on flexible filament (TPU) in relation to these types of extruders? I upvoted anyways, keep them coming! $\endgroup$
    – 0scar
    Commented Apr 10, 2023 at 10:21
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    $\begingroup$ Thanks. Yes, something about TPU can be useful. I'll add it in the future. $\endgroup$
    – kosteklvp
    Commented Apr 10, 2023 at 11:17
  • $\begingroup$ It should be mentioned with "Bowden extruders can suffer from problems with filament control" that you hit these problems hard at speeds far below the point where Bowden becomes an advantage over DD due to lower mass. $\endgroup$ Commented Apr 11, 2023 at 12:52
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    $\begingroup$ To extend this - are there any other configurations for FDM or are these the only two basic designs ? $\endgroup$
    – Criggie
    Commented Apr 12, 2023 at 1:12
  • $\begingroup$ I only heard about a hybrid one. It's called Zesty Nimble. Here is a Teaching Tech's video about it. $\endgroup$
    – kosteklvp
    Commented Apr 12, 2023 at 6:27

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