The beauty of saleable 3D prints lies in their material and print quality. 3D-printed objects that appear lumpy and wavy are not products worthy of the market and subsequently can reduce commissions from sales. It is a rule of thumb that when quality is down, value goes down as well, and business is definitely at risk of collapsing.
A filament spill that occurred during the printing process is usually the most common culprit of these lumps. This happens during the process of Fused Deposition Modeling (FDM), the most popular kind of 3D printing, when the nozzle releases the melted filament to create the desired object.
To prevent this from happening, retraction is utilized. It is a technique that stops the filament from escaping the nozzle.
In this post, we will explore the importance of retraction in 3D printing, and provide tips on how to achieve the correct retraction settings.
What Is Retraction?
In 3D printing, retraction refers to the process of pulling the filament back into the extruder, or nozzle, of the 3D printer. This is typically done to prevent unwanted dripping or excessive stringing of the filament when the printer is moving to a new location on the print bed.
Retraction is controlled by the slicer software, which is used to slice the 3D model into layers and generate the G-code instructions that tell the printer how to build the model. 3D slicing software, such as Cura or PrusaSlicer, can be configured to retract the filament by a certain amount, at a certain travel speed, and after a certain distance of movement during print time.
The 3D slicing software is also sensitive to the extent that it can automatically adjust the travel path to ensure a short minimum travel distance of the nozzle over an open space and, in many cases, avoid crossing an open space all together.
Why Is Retraction Important
Retraction is essential because it allows for a smoother and more precise printing experience. It also helps reduce waste and time spent troubleshooting issues with prints. Without retraction, the filament can droop or sag, causing imperfections in the print.
Retraction is particularly important when printing models with overhangs or bridges, as the nozzle may need to travel across empty space to reach the next point where it will lay down filament.
By retracting the filament material, the nozzle can move more freely without leaving a trail of unwanted filament behind. This can help to improve the quality and appearance of the final print, as well as the overall consistency of the printing process.
Overall, retraction is an important consideration in 3D printing, as it can affect the quality and appearance of the final print. Proper retraction settings can help prevent defects and ensure that the printer produces high-quality, consistent results.
Although various 3D printers have varying retraction settings, the majority of them support the following adjustments:
- Filament distance: This setting lets you regulate how much filament is released from the nozzle.
- Recoil speed: is another name for retraction travel speed, which determines how quickly the nozzle retracts excess filament.
- Minimum displacement: As its name suggests, minimum displacement is utilized to regulate the filament’s minimum length before retraction starts.
Retraction Minimum Travel Distance
The 3D printer’s print head’s travel distance is essential for avoiding stringing problems and creating high-quality output. Depending on the type of filament being used and the speed of your print head, you may need to adjust your minimum travel distance setting.
A low setting can help reduce stringing, but it may also slow the printing process. Using a filament with a high printing temperature and a fast print head speed can lead to too much retraction, which can cause the extruder gears to grind and the nozzles to get clogged.
When setting your minimum travel distance, start by setting it at 1 millimeter. If stringing happens, try increasing the settings in increments of 0.5 millimeters until the problem is fixed. It will give your extruder enough time to move without oozing out too much molten filament.
Faster printheads may need to be slowed down to properly adhere to the build platform and prevent it from shifting or vibrating, leading to poor-quality prints. With a combination of the proper settings and the suitable filament, you can ensure that your 3D printer produces precise, detailed prints every time.
Retraction Speed Settings
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A 3D printer retraction speed is the rate at which the extruder pulls back on the filament. A fast retraction speed is preferable since it quickly releases the pressure on the molten filament.
However, if the filament is pulled back too forcefully, the direct extruder’s gears risk stripping the filament. It is a much more significant issue because you’ll likely need to open the extruder motor to remove the plastic from the gears’ teeth.
Once again, while choosing your retraction speed, keep in mind the characteristics of direct and Bowden extruders. Because of the greater distance between the extruder gear and the hot end, you’ll need to bring in the filament quicker in a Bowden setup.
Starting with a small increment, you can adjust this parameter until you discover the ideal distance for the printed item or working prototype.
We advise starting at the lowest setting and gradually increasing it by 5 mm/s until you encounter no more stringing because a lower setting is kinder to the filament.
The length of filament the extruder will pull back once retraction is activated is known as the retraction distance. Setting it too high will make it take longer for the extruder to engage the filament back towards the nozzle, while setting it too low may not be sufficient to relieve the pressure on the molten filament at the tip of the nozzle.
Even worse, pulling back too much filament can distort the extruder assembly, leading to a clogged nozzle. As a general rule, the retraction distance shouldn’t be higher than the distance between the nozzle and the extruder. It will differ between models of 3D printers and extruders.
Starting with a bit of trial and error, small incremental adjustments can be made on this parameter until you discover the ideal distance for the printed item or working prototype.
For optimal results, you should begin with the smallest retraction distance option and increase it in 1-millimeter steps until no stringing is visible. It is a sensible trade-off that enhances output quality without sacrificing print speed.
All suggested distances, travel, and speed ranges are based on gathered information, laboratory tests, and printed samples.
Watch this for more guidance:
FAQs on What Retraction Is in 3D Printing
More retraction can result in stringing when thin filament strands are left behind on the print. It happens when the extruder pulls back too quickly, and some molten filament is still pushed out before it stops moving.
Other signs of too much retraction include clogged nozzles and grinding gears due to excessive wear on the filament.
Not using retraction can lead to stringing and other print defects. Without the extruder being pulled back, the molten filament will continue to ooze out from the nozzle as it moves across non-contiguous sections of your design.
It can result in poor layer adhesion and weak and poorly defined prints.
The optimal retraction setting will vary depending on the type of filament you are using and the speed of your printhead. Generally, a low retraction distance (1 millimeter or less) is recommended to avoid stringing problems.
If needed, increase this in increments of 0.5 millimeters until you find the best setting for your printer and filament. It is also essential to ensure that the speed of your printhead is fast enough, as this can lead to overshooting or wobbling on the build platform.
Yes, you can adjust retraction settings while printing. If you notice any stringing or other print defects, you can pause the printer and change the retraction settings to see if that resolves the issue.
However, it is recommended to do some test prints first so you can dial in the optimal settings before starting a larger project.
Retraction plays an essential role in the 3D printing process, helping to improve print accuracy while reducing waste and troubleshooting time. The optimal retraction settings will vary from one material to another and from one 3D printer to another.
In addition, the creators of the 3D model give specific recommendations on the retraction speed to be applied for 3D printing their models. You should check the recommendations and try out what worked for them.
Now that we understand what retraction is and how it works, you can experiment to get the perfect finish for your 3D-printed parts.
The ultimate goal of 3D printing technology is to move away from standardization and toward customization, so you can also change the optimal settings and create your own.