Retraction is one of the most useful slicer settings for a 3D printer. It controls how much filament is pulled back after a travel move, and it’s the #1 setting for eliminating retraction and over-extrusion on 3D prints.
There are a few different retraction settings worth taking a look at in your 3D slicer. The two most important ones are the retraction distance and retraction speed, which I suggest setting to 5 mm and 45 mm/s, respectively. I also strongly suggest activating the Z Hop When Retracted feature in your slicer program.
That said, you should also check out the minimum extrusion distance window, maximum retraction count, Combing Mode, and nozzle temperature settings as both also heavily affect the frequency of stringing on 3D printed models.
Want to learn about other best retraction settings?
Table of Contents
What is Retraction?
If you’ve never heard the term “retraction”, it’s a process on 3D printers that involves the extruder pulling back filament from the hot end.
This is done to relieve the hot end of built-up pressure that happens due to the continuous flow of filament. This pressure can cause the melted filament to flow out the nozzle even when the extruder isn’t active, leaving marks of over-extrusion on your prints (e.g. stringing).
Retraction prevents this from happening by equalizing the hot end pressure through retracting (sucking back) filament from the hot end.
Retraction moves are the specific instances where the extruder pulls back the filament. These usually happen at each layer change and when the printhead is moving from one side of a print to another, like if you were 3D printing two models on the same print bed.
Why Use Retraction?
You should use retraction to prevent over-extrusion, especially in the form of stringing, from popping up on your prints.
For reference, over-extrusion, as the name suggests, is a printing problem where too much filament is extruded. Stringing is one way over extrusion can take its shape on a 3D printer, and this specific problem occurs when small whisps (“strings”) of melted filament attach to the exterior of your printed model. It makes your 3D print not only look bad but also a lot less dimensionally accurate.
Check out our article on how to fix stringing issues in your 3D printer here.
Additionally, using retraction in your 3D slicer settings helps prevent other forms of over-extrusion, such as zits and blobs, which can appear on the exterior of your prints.
Now that you know what retraction is and why you should use it, you’re probably wondering how you can control this feature for your 3D printer. In the mini sections below, I’ve gone over the most important slicer settings related to retraction, and I provided recommendations for each setting too!
The most important setting for retraction is the retraction distance. This setting controls how much filament is pulled back for each retraction move.
The higher this value, the more effective each retraction move will be. However, too long of a retraction distance can also cause a hot end jam, so be careful.
For Bowden extruder printers, such as the Ender 3 (Pro/V2), I suggest going with a retraction distance of 5 mm, adjusting in increments of 0.2 mm until you hit 3 or 6 mm. If you’ve reached these values and still are having issues, then it might be time to try using another setting.
And, for direct drive printers, a retraction distance between 1.5 and 2.5 mm should work perfectly. You can also adjust it in increments of 0.2 mm.
The second most important retraction setting is the retraction speed, which controls how fast the extruder moves for each retraction move.
Similar to the distance, the higher the value of the retraction speed settings, the more effective each retraction move. However, going too high might cause issues like jamming.
I suggest using a retraction speed of 40-50 mm/s. I like to use a retraction speed set to the same value as my print speed, as this is considered best practice for the extruder motor (it won’t overheat).
Maximum Retraction Count
The Maximum Retraction Count is the maximum number of retractions that your 3D printer will allow to occur in the Minimum Extrusion Distance Window, which we’ll get to next. A value of 100 should work great, but you can increase it for 3D printing miniatures.
Minimum Extrusion Distance Window
The Minimum Extrusion Distance Window is a setting that controls the space in which the Maximum Retraction Count is enforced. In other words, if this value is set to 10 mm and the Max Retraction Count is set to 5, then a total of 5 retraction moves will be allowed to occur for every 10 mm of filament extruded.
I suggest setting this value to the same as your Retraction Distance. So, in my case, that would be 5.2 mm.
Z Hop When Retracted
Finally, we have the Z Hop When Retracted setting, which is a boolean feature, meaning it can either be turned on or turned off (no numeric value).
When Z Hop When Retracted is activated, the printer will move the nozzle (printhead) up along the Z-axis every time a retraction occurs. This can make the retractions more effective because the nozzle will physically separate from the layer it’s printing before moving. I suggest turning this setting on!
Other Important Settings
There are also a few other settings that are indirectly related to stringing and are worth taking a look at. I’ve briefly gone over three in the sections below.
The combing mode is a slicer setting (in Cura) that defines the rules for how the printhead should move. There are a few options, each with different movement rules.
I suggest setting the combing mode to either “Within Infill” or “Not In Skin”. These modes make the printhead move inside the printing perimeter to prevent stringing and other forms of over-extrusion from occurring on the exterior of your 3D print.
The nozzle temperature is also heavily correlated with over-extrusion and stringing on prints. The higher the temperature of the nozzle, the faster filament will melt and the more easily it will flow out of the nozzle. As such, high nozzle temps can lead to over-extrusion, so consider lowering yours on top of adjusting some retraction settings if you’re dealing with stringing.
The travel speed in your slicer is a setting that controls how fast the printhead moves when it’s not extruding filament (traveling). A higher travel speed will give the filament less time to melt and flow out of the nozzle, thus reducing stringing. As such, I suggest increasing your travel speed if you’re having issues.
How to Test Retraction Settings
You can test your refraction settings by printing a test model specific for stringing, such as the following:
Printing these models will give you a good visual idea of how effective your retraction settings are. And from there, you can evaluate the model and adjust the retraction settings accordingly.
Overall, retraction is a supercritical element of the 3D printing process. If turned off, your prints will likely look hideous as they’ll be full of stringing and other forms of over-extrusion.
It’s a good idea to go into your slicer settings and, first, make sure that you enable retraction. Once it’s turned on, you should adjust some of your retraction settings if you’re having problems with stringing.
The two most important ones are the retraction distance setting and the retraction speed, which I suggest setting to 5 mm and 45 mm/s, respectively. I also strongly suggest activating the Z Hop When Retracted feature in your slicer program.
Finally, you might also want to check the Combing Mode and nozzle temperature settings as both also heavily affect the frequency of stringing on 3D printed models.