Configuring Retraction Settings for PETG – Detailed Guide

As PETG is a type of filament that’s practically notorious for oozing, which can especially come as a shock if you have switched away from PLA filament for the first time, where oozing is much less of an issue, you will want to ensure that your retraction settings are dialed in perfectly for a successful print.

In this guide, we will take you through the process of optimally configuring retraction settings for printing with PETG filament, both for Direct Drive and Bowden extruder 3D printers, which should eliminate the commonly encountered oozing problem and allow you to enjoy your prints without any stringing or blobs in sight.

Additionally, you can also find the example retraction settings we recommend using with PETG filament toward the end of the article if you’re the owner of either a regular Ender 3 with a Bowden extruder or an Ender 3 S1 that comes with a Direct Drive extruder by default, which should help you get started quickly.

Configuring Retraction Settings for PETG – Detailed Guide

For this guide, we will be looking at the retraction distance, retraction speed, retraction minimum travel, maximum retraction count, minimum extrusion distance window, and retraction extra prime amount parameters in Cura, which effectively determine how a retraction will behave.

While you may not have access to every one of these parameters if you aren’t using Cura in particular, they should still give you a good idea of how to configure things.

Retraction Distance

When optimizing retraction settings for PETG, or any other filament for that matter, retraction distance is the first parameter that comes to mind, as it directly determines the length of filament that your 3D printer will pull back from the nozzle whenever a retraction occurs.

cura retraction-distance


When printing PETG filament with a Bowden extruder 3D printer, our recommendation would be to configure your retraction distance value to be in the range of 5 mm to 7 mm as a starting point, which should pull the filament far enough to prevent oozing without wearing it down too much.

On the other hand, if your 3D printer has a Direct Drive extruder, the retraction distance range we recommend using would be 1 mm to 2 mm, as Direct Drive extruders don’t require as much retraction as Bowden extruders due to the absence of the long tube (often referred to as Bowden tube or PTFE tube) that connects the extruder to the hotend in this case.

In a case where the filament distance value you’re using turns out to be higher than optimal, the primary problems you can come across are filament grinding, where the extruder gear ends up stripping the filament, leading to under-extrusion and possibly extrusion stopping altogether, and extruder jamming, where molten plastic ends up in the cold zone of the hotend and blocks the way.

If you come across such a scenario, our recommendation would be to decrease your retraction distance value by 0.5 millimeters at a time, test again, and repeat this process until you find the lowest value where the filament doesn’t ooze out of the nozzle after a retraction, which will be the optimal retraction distance point.

On the other hand, if you end up using a retraction distance value that’s way too low, the problem you will naturally experience is stringing, as the molten material will have plenty of time to make it to the tip of the nozzle and ooze out during long travel moves if your 3D printer doesn’t pull the filament back far enough.

In this case, our recommendation would be to increase your retraction distance by 0.5 millimeters at a time instead and, once again, to keep testing until you arrive at a point where stringing stops being a problem as a result of the filament getting pulled back enough to prevent it from reaching the tip of the nozzle.

With that said, as it’s a whole lot more likely for a retraction value that’s way too high to create more severe problems for the success of the print, such as filament grinding and extruder jamming, as we have mentioned earlier, our recommendation would be to always start from the lower end of the range when calibrating the retraction distance, since this will practically ensure that the worst problem you can end up having will be severe stringing, where the print can still continue.

Alternatively, if you don’t mind spending some time on setting things up initially, another path you can take when configuring your retraction distance value, which will make things more convenient once you’re past the setup process, is to print a retraction tower, which we can describe as the combination of a test 3D model that’s split into different sections to allow you to clearly see the effects of distinct retraction distance (and speed) values within a single print and a Cura post-processing script that automatically adjusts the retraction distance value accordingly for each section.

petg retraction tower 3d model example


While there are numerous ways to print a retraction tower in Cura, we have found the most convenient way to perform this task is to use the Cura Calibration Shapes plugin, which we can practically describe as a test suite that comes with all the necessary 3D models and scripts for calibrating your 3D printer in various ways, whether it’s adjusting print settings such as hotend temperature, retraction speed/distance, and fan speed, correcting the tramming of the bed, or testing support strength.

petg retract tower script distance example


To learn more about how you can use the Calibration Shapes plugin for the task, you can refer to the GitHub page of the plugin and the section regarding the retraction tower component of the plugin in specific, which will take you through the necessary setup and configuration process to get things rolling.

Retraction Speed

Another parameter that plays a vital role in how successful a retraction will be is retraction speed, which determines how quickly the extruder pulls the filament away from the nozzle (and pushes it back in, provided that you haven’t configured the retraction prime speed parameter separately).

cura retraction-distance


When printing PETG, we recommend using a retraction speed value between 20 mm/s and 35 mm/s as a starting point, as staying within this range should practically ensure that your 3D printer will complete the test print successfully without the occurrence of any issues related to the retraction speed.

Upon examining the test print, if you notice large blobs on the surface, particularly at the points where retractions take place, this would effectively signify that the retraction speed value you’re using is way too low, as the slower the speed of the retraction is, the longer time the nozzle will end up staying in the same spot as the retraction is taking place, giving the molten material more time to ooze out of the nozzle and create a blob.

In such a scenario, our recommendation would be to increase your retraction speed value by 5 mm/s, run another test print, and repeat this process until you find the highest retraction speed value where filament grinding doesn’t occur, as this will be the optimal point where the size of the blobs will be minimal and the retractions don’t take longer than they should, which in turn will reduce print times.

On the other hand, if signs of filament grinding are present, whether it’s under-extrusion in some areas of the print or stripped plastic pieces around the extruder gear that grips the filament, it would mean that the retraction speed value you’re using is way too high to the point where the force the extruder gear exerts causes it to eat into the filament.

In this case, our recommendation would be to reduce your retraction speed by 5 mm/s, test again, and repeat this process until you land at a value where filament grinding doesn’t occur anymore, which will allow you to keep the highest retraction speed value possible where filament grinding isn’t an issue anymore.

Additionally, you can also use the retraction tower 3D model and script in the Calibration Shapes plugin to configure the retraction speed the same way you have with the retraction distance, with the only difference being that you will need to select the Speed option from the Command dropdown instead of Distance to keep the retraction distance stable and make the retraction speed dynamic, which is also something to keep in mind.

petg retract tower script speed example


Retraction Minimum Travel

The retraction minimum travel value specifies the minimum length that a travel path needs to be for your 3D printer to retract the filament before moving to the destination, effectively making it a tool that allows you to control the frequency of retractions based on the distance the printhead needs to move.

retraction minimum travel


While reducing the number of retractions may seem like a bad idea at first glance, using the retraction minimum travel limit actually brings two considerable benefits to the 3D printing process, making it a critical part of retraction configuration.

The first and foremost benefit of using this feature is that it can drastically reduce the number of blobs that appear on your prints by preventing the nozzle from coming to a stop for retractions that wouldn’t be necessary at all, considering that such travel moves wouldn’t lead to stringing anyway due to the shortness of the distances, effectively meaning that retracting at such spots would do more harm than good for the quality of your prints.

While it may not be too noticeable, another benefit that the retraction minimum travel feature brings to the table is a reduction in print times, as getting rid of the unnecessary retractions that would otherwise end up wasting time will allow your 3D printer to complete the print in a lesser amount of time, which can add up to a considerable amount of time saved in the long run.

All things considered, when it comes to configuring the retraction minimum travel value, our recommendation would be to start with the Cura default of 1.5 millimeters for printing PETG for your first test print and fine-tune it based on your observations for the best results.

In the scenario where you observe stringing on your test print, particularly across short distances due to lack of retractions, our recommendation would be to decrease the retraction minimum travel value by 0.1 mm, run another test print, and repeat this process until you find the optimal value where stringing doesn’t occur anymore.

On the other hand, if you come across a high number of blobs on your prints, specifically at the points where retractions take place, we recommend increasing the retraction minimum travel by 0.1 mm instead and once again to keep testing until you find the highest value where the increase in the limit doesn’t start creating stringing problems.

Maximum Retraction Count & Minimum Extrusion Distance Window

The minimum extrusion distance window and maximum retraction count values determine the maximum number of retractions your 3D printer will trigger within a particular filament length, where the former specifies the filament length and the latter specifies the number of retractions.

minimum extrusion distance window cura


As an example, if you have your minimum extrusion distance window value set to 7 mm and your maximum retraction count value set to 35, your 3D printer will only be allowed to retract the same 7 millimeters of filament 35 times in total, effectively creating a scenario where a retraction can only take place if your 3D printer’s 35th previous retraction took place more than 7 mm back in terms of filament length.

maximum retraction count cura


This way, you can constrain the amount of contact that the extruder gear makes with each particular portion of the filament in a way that prevents the extruder gear from wearing the filament out to the point where parts of the filament end up chipping away (filament grinding), which would otherwise lead to under-extrusion and possibly extrusion stopping altogether due to the extruder gear not being able to grip the filament anymore.

When it comes to configuring the minimum extrusion distance window, Cura’s recommendation is to go with a value that’s equal or close to the retraction distance value you’re using, and with this in mind, our recommendation would be to simply set the minimum extrusion distance window value to be equal to the retraction distance to get things done quickly and easily.

As modifying either of these values will change the retraction limit, such as either increasing the maximum retraction count or decreasing the minimum extrusion distance window to permit more retractions to take place within a particular length of filament, leaving the minimum extrusion distance window tied to the retraction distance makes calculations more convenient and allows us to use the maximum retraction count value alone to control the limit.

On the other hand, when configuring the maximum retraction count, our recommendation would be to follow the formula of multiplying the minimum extrusion distance window value with 5 as a starting point, such as a maximum retraction count of 35 for a minimum extrusion distance value of 7, which will effectively allow your 3D printer to perform five retractions for each millimeter of filament.

Once you have your test print ready, you can then decrease the maximum retraction count by 5 at a time if you come across signs of filament grinding or increase it by 5 at a time if you notice stringing due to a lack of retractions and keep iterating until you find the value that works best for you.

Retraction Extra Prime Amount

The retraction extra prime amount value specifies the volume of added material your 3D printer will push after priming the filament, effectively creating a scenario where your 3D printer ends up priming more filament than it has retracted.

retraction extra prime amount


he purpose of this feature is to compensate for material lost to oozing during retractions and the following travel moves that would otherwise lead to the issue of under-extrusion after each retraction, whether you will need to configure it or not is purely situational, unlike the rest of the parameters we have talked about so far, and using this feature when it’s not necessary can easily cause your 3D printer to over-extrude after retractions.

So, in the case where you haven’t printed with PETG at all yet or haven’t observed any under-extrusion taking place after retractions and priming, the correct thing to do would be to leave the retraction extra prime amount value at its default of 0 mm^3, which will tell Cura not to apply any compensation.

On the other hand, if under-extrusion after retractions & priming seems to be a frequent problem on your prints, which would clearly indicate that your 3D printer is losing material to oozing after retractions, our recommendation would be to increase this value in small increments, such as 0.05 mm^3 at a time, and to keep testing with higher values until under-extrusion isn’t an issue anymore.

With that said, our recommendation would be to always think of the retraction extra prime amount feature as a last resort or a temporary fix rather than the primary way of preventing the occurrence of under-extrusion after retractions, as taking the necessary steps to get rid of the oozing problem itself, whether by increasing the retraction speed or the retraction distance, will be a whole lot better for the quality of your prints compared to letting the material ooze and compensating for it as a solution.

Example PETG Retraction Settings for Ender 3 (Pro & V2 & Neo)

Below, you can find the example PETG retraction settings that you can use with all Bowden extruder Ender 3 models, including the Ender 3 Pro, Ender 3 V2, Ender 3 Neo, and any combination of these models.

  • Retraction Distance: 7 mm
  • Retraction Speed: 35 mm/s
  • Retraction Extra Prime Amount: 0 mm^3
  • Retraction Minimum Travel: 1.5 mm
  • Minimum Extrusion Distance Window: 7 mm
  • Maximum Retraction Count: 35

Example PETG Retraction Settings for Ender 3 S1

Below, you can use the PETG retraction settings that you can use with an Ender 3 S1, where things are slightly different than the rest of the Ender 3 models due to it coming with a Direct Drive extruder by default.

  • Retraction Distance: 1.5 mm
  • Retraction Speed: 35 mm/s
  • Retraction Extra Prime Amount: 0 mm^3
  • Retraction Minimum Travel: 1.5 mm
  • Minimum Extrusion Distance Window: 1 mm
  • Maximum Retraction Count: 10

Conclusion

With your retraction settings now configured correctly for printing with PETG filament, plastic oozing out of the nozzle shouldn’t be a problem for your prints anymore, whether it’s the blobs that appear all over the surface and reduce the visual quality or the stringing that can be a real bother to clean when it’s severe.

That being said, it’s once again worth noting that finding the most optimal settings will always come down to rigorous testing with many different values for the retraction parameters tried, which is why we highly recommend to keep testing until you have things set up to be as close to perfect as possible before moving forward with an actual print.