The long PTFE tube that the filament travels through as the extrusion takes place, known as the Bowden tube, is usually the first thing that comes to mind when we think of extruders, as this type of extruder assembly, known as the Bowden extruder, is extremely common, with popular printers such as the Ender 3 utilizing it.
On the other hand, it’s entirely possible for an extruder to not have this PTFE tube at all, as there is an alternative to the Bowden extruder, known as a direct-drive extruder, where the extruder assembly and the hotend assembly reside in the same area, eliminating the need for the tube.
In today’s article, we will be talking about configuring the retraction settings specifically for direct drive extruders, which is one of the essential steps to take when switching to a direct drive extruder for the first time due to the retraction requirements of a direct drive extruder being different than a Bowden extruder’s retraction requirements.
So, how can you configure retraction settings specifically for direct drive extruders?
When configuring retraction settings specifically for direct drive extruders, the only modification you will need to make is to decrease the Retraction Distance value by a considerable amount, as the distance between the extruder and the nozzle is much smaller compared to a Bowden extruder.
In the upcoming sections, we will be discussing configuring retraction settings for direct drive extruders in more detail, find out why direct drive extruders require different retraction settings than Bowden extruders, and finally, go through what would happen in cases where Bowden-suitable retraction settings are used for a direct drive extruder.
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How to Configure Retraction Settings for Direct Drive Extruders?
While direct drive extruders indeed require retraction settings to be configured differently compared to Bowden extruders, the differences are pretty straightforward and do not involve any technical complexity that would make the configuration process challenging.
In essence, correctly configuring retraction settings for a direct drive extruder is as straightforward as decreasing the Retraction Distance to a much lower value than what is standard for a Bowden extruder.
While Bowden extruders often require at least 5 millimeters of distance for a successful retraction, with the optimal value falling in the range of 5 mm to 10 mm in most cases, direct drive extruders can operate with a Retraction Distance value as low as 0.5 millimeters, with 0.5 mm to 2 mm considered a fairly standard range.
As the rest of the retraction settings are not related to the distance between the extruder and the nozzle, you can use the values you already have at hand for these parameters regardless of the type of extruder you’re utilizing.
Why Do Direct Drive Extruders Require Distinct Retraction Settings?
Since the distance that the filament travels with a direct drive extruder is much shorter than the distance it needs to travel with a Bowden extruder, it’s actually entirely natural for direct drive extruders to require retraction to be configured separately.
Considering that the Retraction Distance parameter determines how far back the filament will be pulled from the nozzle when a retraction takes place, the distance between the extruder and the nozzle is one of the primary factors to keep in mind when tuning this value.
In the case of a Bowden extruder, this distance is a considerably long one due to the hotend and the extruder being two separate components connected with the PTFE tube, which requires the Retraction Distance value to be significant for the retraction to have the intended effect.
On the other hand, in the case of a direct drive extruder, the extruder and the nozzle are practically right next to each other, meaning the usage of a smaller Retraction Distance value is enough for the retraction to achieve the intended effect of pulling the filament away from the hotend.
As the purpose of retraction is to pull just the right amount of filament to prevent oozing from taking place, reducing the Retraction Distance value when utilizing a direct drive extruder is an essential optimization that needs to be performed.
What Happens If You Use Bowden Retraction Settings for a Direct Drive Extruder?
Since using retraction settings that are suitable for a Bowden extruder with a direct drive extruder essentially means that you are misconfiguring the retraction, your 3D prints will suffer from the same standard issues that would take place when you misconfigure the retraction due to any other reason.
If you use a Retraction Distance value optimized for a Bowden extruder when using a direct drive extruder, you will practically be using a Retraction Distance value that is way too high and, as a result, experience the standard set of issues that come with it.
While the most common problem that using a higher-than-optimal Retraction Distance value would create is under-extrusion due to the filament not making its way back to the nozzle on time, it’s also possible for issues such as filament grinding or even an extruder jam to take place in more severe cases.
It’s also worth mentioning that the usage of a too high Retraction Distance value is not a direct drive extruder-specific issue by any means, meaning the problems we have discussed above can affect both types of extruders in the case of a misconfiguration.
As there is practically nothing complicated about configuring the retraction settings specifically for a direct drive extruder, once you know that it requires a different configuration, you should be able to perform the necessary adjustments within a few minutes and get back to enjoying your 3D printer.
To quickly recap, when adjusting the retraction settings to make them compatible with a direct drive extruder, the only modification you will need to make is to reduce the Retraction Distance to a value that falls between the range of 0.5 mm to 2 mm, as opposed to the 5 mm to 10 mm range you would use with a Bowden extruder.
As the distance between the hotend and the extruder is much shorter in the case of a direct drive extruder, when compared to a Bowden extruder, the optimal length of filament that should be retracted is also much smaller as a result.
Mike started his 3D printing journey with the Anet A8 when it first came out back in 2017, and has been obsessed with 3D printers ever since. Nowadays, he primarily uses his Ender 3 to print functional parts that make his life more convenient whenever possible.