Enabling retraction is the most common method used to combat 3D printer stringing. Enabling retraction means that, where the extruder has to cross an empty space, the filament will be pulled back – just a little bit – by the feeder. This prevents the molten plastic from trailing behind as the printer head moves because the “pulling back” action serves as a countermeasure against oozing. Once the extruder has arrived at the next location, the filament is pushed back out, and printing resumes from the nozzle again.
In most slicing applications, like Cura, retraction is usually enabled by default. However, it’s always a good idea to confirm that this is true, especially when you start experiencing stringing. If the retraction setting is turned on and you’re still experiencing 3D printer stringing, you may then need to go into the “nitty gritty” of the retraction settings:
Retraction distance is probably the most critical retraction setting, as it determines how far the filament travels. Generally, if your nozzle can retract further, it means you are less likely to encounter 3D printer stringing. But again, if you retract too far, the filament may be unavailable in the hot end when you need to resume printing.
The retraction distance may vary depending on the type of extruder you are using. However, a Bowden extruder will typically require a higher retraction distance, owing to the longer distance between the nozzle and the drive gear.
To determine the correct retraction distance, you may have to perform test prints. Try this retraction test print. It prints quickly and does not require too much filament.
The retraction speed determines how quickly the filament is retracted. A faster retraction speed suggests that 3D printer stringing is less likely to occur because the filament is pulled back fast enough before it starts oozing. However, when the retraction speed is too fast, it may cause the filament to disconnect with the other portion inside the nozzle. Worse, a quick movement of the drive gear may grind the molten plastic and jam the nozzle or create areas where the filament is not deposited.
Therefore, you should aim to find a sweet spot (between slow and fast), where retraction is optimal. This sweet spot may vary depending on the printing material. Perform a few test prints to determine the ideal retraction speed.
If you’re still unsure of what to do, check out Simplify3D. This program comes with pre-configured profiles that are a great place to start if you are looking for a retraction speed that works best.
What Settings Should You Use?
To determine the optimal retraction values, you must first know the extruder you will be using and the material you will be printing with.
According to Pinshape, materials like ABS and PLA will do well with a speed of 40-60 mm/s and a retraction distance of 0.5-1.0 mm on direct drive extruders. On the other hand, Bowden extruders will generally require a speed of 30-50 mm/s, with a retraction distance of around 2.0 mm. These figures are not constant and can change based on many variables.
At the end of the day, when retraction is done correctly, it is effective at ending stringing, and it will give you more control over your prints. Some slicer programs, like Simplify3D, come with ‘coast’ and ‘wipe’ parameters that are powerful tools for further dialing in your retraction values.