3D printer retraction speed

How to Get the Best Retraction Length & Speed Settings – 3D Printerly

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.


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

It is the best technique to get the best suitable retraction settings. Print a small object just for retraction tests that can be printed in a short period.

Start the printing process by changing the retraction speed and retraction distance step by step and see where the printer is performing well. Start printing the actual object when you are completely satisfied with the retraction tests print.

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.

If you are facing any problem even after changing the retraction setting, try to use filament materials that are comparatively flexible because these types of filament will work properly on the low retraction speed as well.

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 from within Cura where you can also insert scripts to best test retraction settings, one at a time.

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 50mm/s and if you notice any issues in the filament, try decreasing the speed by 10 mm and stop when you notice improvements.
  • Retraction Distance: On Ender 3, the retraction distance should be within 2mm to 8mm. Begin at 5mm and then adjust it until the nozzle stops oozing.
  • Max Retraction Cont: “10” is considered as the ideal choice, only change this count if you feel any issue in the printing process.

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, then have 3mm, 4mm, 5mm, up to 8mm and see which retraction setting gives the best results.

What 3D Printing Problems Do Retraction Settings Fix?

As it is 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 by keeping every aspect in mind 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 completely destroy the beauty and charm of your 3D print.

When the retraction speed or retraction length cannot match, the filament will drop or ooze from the nozzle, and these 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.

Stringing or Oozing

Stringing or Oozing

Stringing (otherwise known as oozing, whiskers, or “hairy” prints) occurs when small strings of plastic are left behind on a 3D printed model. This is typically due to plastic oozing out of the nozzle while the extruder is moving to a new location. Thankfully, there are several settings within Simplify3D that can help with this issue. The most common setting that is used to combat excessive stringing is something that is known as retraction. If retraction is enabled, when the extruder is done printing one section of your model, the filament will be pulled backwards into the nozzle to act as a countermeasure against oozing. When it is time to begin printing again, the filament will be pushed back into the nozzle so that plastic once again begins extruding from the tip. To ensure retraction is enabled, click “Edit Process Settings” and click on the Extruder tab. Ensure that the retraction option is enabled for each of your extruders. In the sections below, we will discuss the important retraction settings as well as several other settings that can be used to combat stringing, such as the extruder temperature settings.

Common Solutions

Retraction distance

The most important retraction setting is the retraction distance. This determines how much plastic is pulled out of the nozzle. In general, the more plastic that is retracted from the nozzle, the less likely the nozzle is to ooze while moving. Most direct-drive extruders only require a retraction distance of 0. 5-2.0mm, while some Bowden extruders may require a retraction distance as high as 15mm due to the longer distance between the extruder drive gear and the heated nozzle. If you encounter stringing with your prints, try increasing the retraction distance by 1mm and test again to see if the performance improves.

Retraction speed

The next retraction setting that you should check is the retraction speed. This determines how fast the filament is retracted from the nozzle. If you retract too slowly, the plastic will slowly ooze down through the nozzle and may start leaking before the extruder is done moving to its new destination. If you retract too quickly, the filament may separate from the hot plastic inside the nozzle, or the quick movement of the drive gear may even grind away pieces of your filament. There is usually a sweet spot somewhere between 1200-6000 mm/min (20-100 mm/s) where retraction performs best. Thankfully, Simplify3D has already provided many pre-configured profiles that can give you a starting point for what retraction speed works best, but the ideal value can vary depending on the material that you are using, so you may want to experiment to see if different speeds decrease the amount of stringing that you see.

Temperature is too high

Once you have checked your retraction settings, the next most common cause for excessive stringing is the extruder temperature. If the temperature is too high, the plastic inside the nozzle will become less viscous and will leak out of the nozzle much more easily. However, if the temperature is too low, the plastic will still be somewhat solid and will have difficulty extruding from the nozzle. If you feel you have the correct retraction settings, but you are still encountering these issues, try decreasing your extruder temperature by 5-10 degrees. This can have a significant impact on the final print quality. You can adjust these settings by clicking “Edit Process Settings” and selecting the Temperature tab. Select your extruder from the list on the left, and then double-click on the temperature setpoint you wish to edit.

Long movements over open spaces

As we discussed above, stringing occurs when the extruder is moving between two different locations, and during that move, plastic starts to ooze out of the nozzle. The length of this movement can have a large impact on how much oozing takes place. Short moves may be quick enough that the plastic does not have time to ooze out of the nozzle. However, long movements are much more likely to create strings. Thankfully, Simplify3D includes an extremely useful feature that can help minimize the length of these movements. The software is smart enough that it can automatically adjust the travel path to make sure that nozzle has a very short distance to travel over an open space. In fact, in many cases, the software may be able to find a travel path that avoids crossing an open space all together! This means that there is no possibility to create a string, because the nozzle will always be on top of the solid plastic and will never travel outside the part. To use this feature, click on the Advanced tab and enable the “Avoid crossing outline for travel movement” option.

Movement Speed

Finally, you may also find that increasing the movement speed of your machine can also reduce the amount of time that the extruder can ooze when moving between parts. You can verify what movement speeds your machine is using by clicking on the Speeds tab of your process settings. The X/Y Axis Movement Speed represents the side-to-side travel speed, and is frequently directly related to the amount of time your extruder spends moving over open air. If your machine can handle moving at higher speeds, you may find that increasing this settings can also reduce stringing between parts.

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