As the FDM printer nozzle moves through the open space to the next point, molten plastic sometimes oozes out, which then solidifies and sticks to the printed part. It is 3D printingThe “stringing” phenomenon caused by the machine will cause fine plastic lines similar to spider webs or strands of hair to appear on the 3D printed parts.
Theoretically, plastic should not settle as the nozzle moves (also called displacement) in the open air. However, melted plastic often flows onto parts where it shouldn’t, causing the print to appear “whisker-like.”
The main causes of stringing in FDM printers are incorrect shrink settings and too high hot exit temperature settings. For example, PETG requires relatively high temperatures to melt and is prone to spinning. PLA and ABS also have this problem.
This itemmagic monkey networkI will learn with you five simple methods to solve the problem of 3D printing wire drawing, and hope everyone can print perfect works.
Enable retraction
Enabling retraction is the most common way to resolve stringing issues on 3D printers. Enabling retraction means that when the extruder needs to pass through a certain gap, the filament will be pulled back (just a little) by the feeder. This prevents molten plastic from hanging around when the print head moves, as the “pull back” action acts as a countermeasure against leaks. Once the extruder reaches the next position, the filament is pushed out and printing resumes from the nozzle.
In most clipping apps, such as Cura, shrinking is usually enabled by default. However, if the retraction settings are enabled and you are still experiencing 3D printer chain pulling issues, you may want to dig deeper into the specifics of the retraction settings:
retraction distance
Retraction distance is probably the most critical retraction parameter because it determines how far the filament travels. Generally speaking, if your nozzle can be retracted further, it means you are less likely to experience strings on your 3D printer. But again, if you retract it too much, the filament may not be available at the hot end when you need to resume printing.
To determine the correct retraction distance, you may need to perform a test print.
retraction speed
The retraction speed determines how quickly the filament retracts. Faster retraction speeds indicate that the 3D printer is less likely to become stringy, as the filament is removed relatively quickly before it begins to bleed. However, retracting too quickly can cause the filament to become disconnected from the rest of the nozzle. Worse yet, the rapid movement of the drive gear can grind up the molten plastic and clog the nozzle or create areas where the filament won’t settle.
Therefore, you should aim to find a sweet spot (between slow and fast) where retraction works best. This sweet spot may vary depending on the print media. Perform several test prints to determine the ideal removal speed.
What parameters should be used?
Different shrink settings can significantly increase or decrease blobs (Source: Sennar59 via Reddit)
To determine the optimal shrinkage value, you must first understand the extruder and print material you are using.
On a direct drive extruder, materials such as ABS and PLA typically have speeds of 40 to 60 mm/s and shrink distances of 0.5 to 1.0 mm. These numbers are not set in stone and can change depending on many variables.
Some clipping programs (such as Simplify3D) come with “pan” and “wipe” settings, which are powerful tools for further adjusting the zoom value. As the name suggests, “wipe” moves the nozzle against the exterior wall to wipe away any remaining plastic, while “glide” stops the extruder at the last few millimeters of the print line to reduce pressure buildup and avoid large pieces or stains.
In Cura, the “Minimum Retract Travel” setting prevents the printhead from retracting unless the printhead is moved a certain distance. This prevents the filament from fraying. Another setting to consider is “comb mode”, which controls the movement of the printer to avoid unnecessary retraction. All retraction settings can be found in Cura’s “Move” drop-down menu.
Ultimately, if retraction is done correctly, it will prevent stringing and give you more control over your print.
Set the right temperature
This model will help you find the ideal temperature (Source: dede67 via Thingiverse)
As the temperature increases, the print material becomes more liquefied and is more likely to drip from the nozzle, even after adjusting the retraction setting. Lower nozzle temperatures reduce this possibility. Be careful, however, not to set the temperature too low. Extremely low temperatures can prevent the filament from melting and cause extrusion issues.
The ideal temperature depends on the printing material and other printing parameters. However, once the wiring is discovered, it is generally recommended to lower the temperature. You can try lowering the nozzle temperature by 5-10°C, but never lower the temperature below the manufacturer’s minimum specifications. Here are the generally recommended nozzle temperatures for some of the most popular supplies:
PLA: 180-220℃
ABS: 210-250°C (print bed 90-110°C)
PETG: 220-250℃
TPE: 210-260°C (printing bed 20-110°C)
PVA: 160-215°C (printing bed 60°C)
TPU: 210-230°C (print bed 30-60°C)
Testing your prints using a temperature calibration tower is a great way to determine the ideal temperature for each print material.
Adjust print speed
Printing speed also affects the drawing of the 3D printer filament. For example, if the nozzle moves between two points for too long, strings may occur because the molten plastic has more time to escape the nozzle. But if the extruder is moving faster, a short period of movement may be fast enough that the filament doesn’t have enough time to flow.
Increasing the speed at which the nozzle moves when it’s not printing can reduce 3D printer spinning, but if the temperature is low and the print speed is too high, you may end up with under -extrusion because the plastic does not have enough time to drain. .
Generally speaking, speeds of 190 to 200 mm/s are suitable for most print media. As a 3D printer, you should confirm the speed your printer uses before making any adjustments. For example, the moving speed on the X/Y axis represents the moving speed from side to side, which is directly related to the length of time the nozzle moves in empty space.
Clean the nozzles thoroughly before printing
You can use a brush to clean the nozzle of your 3D printer (Source: Airwolf 3D)
When you use a printer for an extended period of time, especially with a single type of material like PETG, the filament may leave a thin layer of residue inside and outside the nozzle. This layer of residue can cause the 3D printer to warp as the filaments attempt to stick to the surface of the printed part.
To avoid this problem, be sure to clean the nozzles thoroughly before printing. Start from the outside of the nozzle and wipe it with a damp cloth while it’s still warm. This will clear debris from the outside of the nozzle, but you may need to use a wire brush or small blade to remove any remaining material.
Next, you will need to work inside the nozzle to clean out any debris blocking the exit hole. The easiest way is to insert a small needle or drill into the nozzle. This breaks down the dirt and cleans the nozzle. However, if that doesn’t work, you can also try cold drawing to remove any remaining dirt from the previous wire.
If you still have problems after cleaning using the method above, you may need to replace the nozzle. Just be sure to heat the hot end to melt the material stuck inside and remove the filament feeding the extruder. Once all remaining material has been removed, the nozzle can be removed. Next, use a small metal pick to clean the hot end before installing the new nozzle.
Keep filaments away from moisture
A sealed dry box can protect your filament from moisture (Source: mcfada via Instructables)
Humidity in the air can damage the filament and cause stringing. Once moisture is present, the plastic turns to vapor when heated. This vapor can mix with plastic, increasing the risk of leaks during processes other than printing. Polylactic acid is the main culprit because it tends to absorb more moisture than ABS and other materials. However, all FDM 3D printing filaments are hygroscopic to some extent.
If heavy spinning occurs, it means your filament is wet and needs to be dried and stored.
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