There are many settings that we can adjust and improve on our 3D printers, one of them being retraction settings. It took me a while to figure out how important they were, and once I did, my 3D printing experience changed for the better.
Many people don’t realize how important retraction can be until they are troubleshooting poor print quality in certain models.
Retraction settings are related to the speed and length at which your filament is pulled back within your extrusion path, so the melted filament at the nozzle doesn’t leak out while moving. Retraction can improve overall print quality and stop print imperfections such as blobs and zits.
What is Retraction in 3D Printing?
When you hear that rotating noise backwards and see filament actually getting pulled back, that is retraction occurring. It is a setting which you’ll find in your slicer software, but it isn’t always enabled.
After you have understood the basics of printing speed, temperature settings, layer heights and widths, then you start to get into the more nuance settings like retraction.
We can be specific on telling our 3D printer how exactly to retract, whether that be the length of retraction, or the speed at which the filament is retracted.
Accurate retraction length and distance can reduce the chances of different problems mainly the stringing and oozing.
Now that you have a basic understanding of retraction in 3D printing, let’s explain the basic retraction terms, retraction length and retraction distance.
1. Retraction Length
Retraction distance or retraction length specifies the length of the filament that will be extruded from the nozzle. The retraction distance should be adjusted accurately because both too low and too high retraction distance can cause printing problems.
The distance will tell the nozzle to pull back the amount of filament according to the specified length.
According to the experts, the retraction distance should be between the 2mm to 7mm distance for Bowden extruders and should not be more than the length of the printing nozzle. The default retraction distance on Cura is 5mm.
For Direct Drive extruders, retraction distance is on the lower end, of around 1mm to 3mm.
While adjusting the retraction distance, increase or decrease it in small increments to get the best suitable length because it varies depending on the type of filament you are using.
2. Retraction Speed
Retraction speed is the rate at which the filament will retract from the nozzle while printing. Just like the retraction distance, setting the most suitable retraction speed is necessary to get better results.
Retraction speed should not be too low because the filament will begin to ooze from the nozzle before it reaches the exact point.
It should not be too fast because the extruder motor will reach the next location quickly and the filament will extrude from the nozzle after a short delay. A distance too long can cause a decline in print quality because of that delay.
It can also result in the filament getting ground and chewed up when the speed generates too much biting pressure and rotation.
Most of the time the retraction speed works perfectly at its default range but you may need to adjust it while switching from one filament material to another.
How to Get the Best Retraction Length & Speed Settings?
To get the best retraction settings you can adopt one of the different ways. Implementing these processes will surely help you to get the best retraction settings and print the object just as you expected.
Notice that the retraction settings will be different depending on the fact that whether you have a Bowden setup or a Direct Drive setup.
Trial and Error
Trial and error is one of the best techniques to get the best retraction settings. You can print a basic retraction test from Thingiverse which doesn’t take very long.
Based on the results, you can then start to adjust your retraction speed and retraction distance little by little to see if you get improvements.
Changes Between Materials
The retraction settings are usually different for every filament material being used. You have to calibrate the retraction settings accordingly every time you use a new filament material such as PLA, ABS, etc.
Cura has actually released a new method to dial in your retraction settings directly within the software.
The video below by CHEP explains it really well so check it out. There are specific objects that you can put on your build plate within Cura, along with a custom script that automatically changes retraction settings during the print so you can compare within the same model.
Cura Retraction Settings on Ender 3
The Cura retraction settings on Ender 3 printers usually include different settings and the ideal and expert choice for these settings will be as follows:
- Retraction Enabling: First, go to the ‘Travel’ settings and check the ‘Enable Retraction’ box to enable it
- Retraction Speed: It is recommended to test a print at the default 45mm/s and if you notice any issues in the filament, try decreasing the speed by 10mm and stop when you notice improvements.
- Retraction Distance: On Ender 3, the retraction distance should be within 2mm to 7mm. Begin at 5mm and then adjust it until the nozzle stops oozing.
The best thing you can do on your Ender 3 is implement a retraction tower to calibrate the best retraction settings. How this works is you can set your Ender 3 to use increments of each setting per ‘tower’ or block to see which gives the best quality.
So, you would do a retraction tower to start with a retraction distance of 2mm, to move up in 1mm increments to 3mm, 4mm, 5mm, up to 6mm and see which retraction setting gives the best results.
What 3D Printing Problems Do Retraction Settings Fix?
As mentioned above, stringing or oozing is the major and most common problem that occurs just because of wrong retraction settings.
It is essential that the retraction settings should be calibrated accurately to get a well-crafted, high-quality print.
Stringing is referred to as a problem in which the print has some strands or threads of filament between two printing points. These strands occur in an open space and can mess up the beauty and charm of your 3D prints.
When the retraction speed or retraction distance isn’t calibrated, the filament can drop or ooze from the nozzle, and this oozing results in stringing.
Most of the 3D printer experts and manufacturers suggest adjusting the retraction settings to avoid the oozing and stringing problems effectively. Calibrate retraction settings according to the filament you are using and the object you are printing.
How to Avoid Stringing in Flexible Filament (TPU, TPE)
Flexible filaments such as TPU or TPE are used for 3D printing because of their amazing non-slip and impact resistance properties. Keep this fact in mind that flexible filaments are more prone to oozing and stringing but the problem can be stopped by taking care of printing settings.
- The first and most important thing is to enable retraction settings every time you are using flexible filament.
- Set up a perfect temperature because high temperatures can cause the problem as the filament will melt quickly and may start dropping.
- Flexible filaments are soft, do a test print by adjusting retraction speed and retraction distance because a bit of difference can cause stringing.
- Adjust the cooling fan according to the printing speed.
- Focus on the flow rate of the filament from the nozzle, usually flexible filaments work well at 100% flow rate.
How to Fix Too Much Retraction in 3D Prints
It’s definitely possible to have retraction settings that are too high, leading to printing issues. One issue would be a high retraction distance, which would cause filament to retract too far back, leading to filament being closer to the hotend.
Another issue would be a high retraction speed which might reduce the grip and not actually retract properly.
To fix retractions that are too high, turn your retraction distance and speed down to a lower value to see if it fixes retraction issues. You can find some standard retraction settings for your extruder and 3D printer in places like user forums.