What Is 3D Print Stringing?

In the 3D printing process, this is just how it happens. An FDM printer nozzle runs through open space to arrive at the next point. In the process, it may occasionally ooze melted plastic, which then thickens and glues to the 3D printed pieces. That right there is 3D printer stringing. 3D printer stringing sometimes even leaves your 3D printed pieces with tiny threads of plastic residues that look like strands of hair or cobwebs.

In a normal situation, your nozzle should not leave plastic residues as it runs through open-air (also known as a travel move). Nevertheless, the molten plastic has a habit of spilling onto portions where it is not needed. This is what makes your 3D prints appear like they have whiskers on.

Spurs Of 3D Printer Stringing

The two major spurs of stringing in FDM 3D printers include:

·        Making use of wrong retraction settings

·        Putting the hot end temperature level too high.

For instance, PETG as a 3D printer type needs somewhat high-temperature levels to handle the melting process. This need is why this type of 3D printer is infamous for stringing. PLA and ABS see also familiar faces when it concerns 3D printer stringing.

If you have constantly face this problem or you are presently, then, you are in luck today! There are certain measures to prevent the occurrence of 3D printer stringing. Check them out!

Ways To Prevent 3D Printer Stringing

1.      Enable Retraction

We have chosen this as our first remedy in this section due to its popularity and effectiveness. Once you enable retraction, you have just effectively rid yourself of the hassles of 3D printer stringing. Enabling retraction implies that, instead of the extruder to move through a vacant area, the filament will be retracted slightly by the feeder.

This staves off the molten plastic from tailing the printed piece as the printer head motions forward. This is as the “retracting” effort comes in as a countermeasure to prevent oozing. As soon as the extruder reaches the next point, the filament is pushed back out. Immediately, the printing process right again, right from the nozzle point.

Just like Cura, most slicing software enables the retraction action automatically.  Still, you cannot be too sure. So ensure that you check to be sure that it has been enabled. If you haven’t, you should do so now, particularly if you are now battling with stringing issues. If you have confirmed that the retraction setting has been turned on and yet, you still have to deal with 3D printer stringing, you may at this point require to delve into the crux of the retraction settings. Dive in!

Retraction Distance

Retraction distance is perhaps the most significant retraction setting, as it defines how long the filament moves. Principally, if your nozzle can retract more, it means you have a lesser odds of experiencing 3D printer stringing. Yet again, if the retraction goes too far, the filament may be out of reach in the hot end when you are ready to continue printing.

The distance of the retraction may be different based on the kind of extruder you use. Yet, a Bowden extruder will naturally need a longer retraction distance, due to the protracted space between the drive gear and the nozzle.

To know the right retraction distance, you may need to run some initial test prints. This test print should help. It is very fast and does not need excess filament.

Retraction Speed

Another part of this setting is the retraction speed that defines how swiftly the filament gets retracted. A quicker retraction speed implies that 3D printer stringing is less probable as the filament is retracted just in time to avoid the oozing stage. But, when the retraction speed is too quick, it may result in the filament getting severed from the other part inside the nozzle. In a worse case, an abrupt motion of the drive gear may scrape the molten plastic and block the nozzle or produce points where no filament is inserted.

Thus, you should attempt to locate a good equilibrium between slow and fast, where retraction is the best. This good equilibrium may differ based on the material used to print. Conduct some test prints to deduce the appropriate retraction speed.

If you still have doubts about the steps to take, Simplify3D can help you out.

What Settings Should You Use?

To deduce the best retraction values, you should have an idea of the extruder to be used as well as the material for printing

Materials like ABS and PLA work best at a speed of 40-60 mm/s. A retraction distance of 0.5-1.0 mm on direct drive retraction is also their best retraction distance. On the flip side, Bowden extruders will typically need a retraction rate of 30-50 mm/s, and a retraction distance set at about 2.0 mm. These settings can vary relying on various variables.

Eventually, when you have been able to retract correctly, it becomes a potent tool for combating stringing issues. This situation gives you more leverage over how your printed items come out. Some slicer software, like Simplify3D, is programmed with default ‘coast’ and ‘wipe’ parameters that are influential devices for additional dialing in your retraction values.

2.     Select the Appropriate Temperature Level

 Even when you have worked well on the reaction settings, a continuous increase in the temperature level would lead to the printing material getting more liquefied. This opens up the likelihood of having it drip from the nozzle. A decreased temperature level lessens this probability. Still, you must take note so the temperature is not too low. When the temperature level is too low, the filament might not melt as well as it should, which could lead to difficulties in extrusion.

A perfect temperature hinges on the printing material used for printing and some other printing settings. Although, it is commonly advised to reduce the temperature immediately you notice a case of stringing. You can begin by decreasing the nozzle temperature level by 5-10 °C increments, but ensure it does not go below the manufacturer’s lowest specifications. These are the temperature levels that are often recommended for some of the most popular filaments:

• PET: 215-235 °C
• PLA: 180-220 °C
• TPU: 230-250 °C (60 °C print bed)
• PVA: 160-190 °C (60 °C print bed)
• TPE: 210-240 °C (20-70 °C print bed)
• ABS: 200-250 °C (90-100 °C print bed)

With the help of a temperature calibration tower test print, you can easily identify the ideal temperature for each printing material.

3.     Clean The Nozzle Thoroughly Before You Print

After you have used a 3D printer for a relatively long time, particularly if you had used it the whole time with just one kind of printing material (PETG for example), the filament can drop off a tiny row of residues inside the nozzle. This tiny bit of residue can result in 3D printer stringing. This is the case as filament strands will attempt to get attached to the body of your printed piece.

If you must prevent this type of difficulty from happening, be sure to have your nozzle cleaned thoroughly before you do any printing. That way, you can remove any dirt from the prior filaments.

4.     Ensure Your Filaments Are Free From Moisture