Filament Grinding: Causes and Solutions
When the extruder pulls plastic from the filament instead of pushing it through the hot end, a typical issue that occurs in 3D printing is known as filament grinding. If you do this while printing with colored filament, you may hear a grinding or clicking sound from the extruder motor and see powder particles in the filament. If your 3D printer is experiencing filament grinding issues, read this article to learn how to fix it.
What Is Filament Grinding?
The extruder "grinds" the material, which can be a frustrating issue if you've never had to deal with it. This is the most common cause of filament jams when the extruder gear continues to turn. Rather, it continues operating and uses its toothed gear to remove the filament.
The filament becomes too concave for the extruder gear to handle when this occurs. Seeing chips or strips of filament in a specific area surrounding the extruder is a telltale sign of filament grinding.
We have some solutions, but we know how frustrating this situation is and how difficult it may be to fix. However, to find the right remedy, you must first determine the reason, which we will do in the following part.
What Causes Filament Grinding?
1. Inadequate Lubrication
Not using enough lubricant during the extrusion process is a major cause of filament grinding. Without proper lubrication, the filament can grind against the extruder walls due to excessive friction. Among the many potential causes of inadequate lubrication are:
Grinding can occur when the filament is either too dry or has an insufficient amount of lubricating dealers. Grinding is more likely to occur during printing with dry filament because of its increased susceptibility to friction-related issues.
When debris, grime, or other impurities accumulate inside the extruder, it can hinder the proper movement of the filament, leading to increased friction and grinding. To avoid this problem, be sure to clean and repair the extruder regularly.
2. Nozzle Having Blockages or Clogs
A partially or completely blocked nozzle is another typical cause of filament grinding. If the nozzle gets clogged, the extruder will grind to get the filament through, which will interrupt its easy drift. When dust, filth, or other particles build up on the filament, they might transfer to the nozzle and cause frequent jams. Filaments that are unsightly or poorly stored can also be a source of contaminants.
3. Extruder Calibration and Tension Issues
One major factor that might lead to filament grinding is using the wrong tension settings and incorrectly calibrating the extruder. Overly high tension or improper extruder calibration might cause the filament to grind against the extruder gear or hobbed bolt due to excessive pressure applied to it. Grinding can occur if the extruder fails to feed the filament continuously due to inaccurate SPU calibration. Properly calibrating the extruder is essential for precise filament management.
4. Wrong Printing Speed and Temperature
One factor that can lead to filament grinding is using the wrong printing speed and temperature settings. Grinding issues may arise as a result of the combined effects of these factors on filament float and its interactions with the extruder. Factors related to printing speed and temperature include:
When you print at really high rates, the extruder could pull too hard on the filament, which can grind it. The filament will shred because it can't melt and waft easily with fast movements.
Mistakes in the filament's temperature settings might cause float and irregular melting. Grinding can occur when the extruder tries to force the filament through the nozzle because it hasn't melted sufficiently due to an extremely low temperature.
How Can You Fix It?
We will get into the important solutions for filament grinding now that you know some of the causes! To put it simply, you should eliminate all potential causes of filament grinding.
1. Adjust the hot end temperature
Maybe you're worried that the filament isn't coming out fast enough. Put the hot end to the typical printing temperature and feed some filament through it by hand, being careful not to move it too quickly. As you push down on the filament, you want it to extrude at a rate close to your speed. Turn up the nozzle temperature if you see that the filament isn't melting fast enough.
2. Level the Bed
A self-leveling probe, like the BLTouch, may make short work of this task. In that case, you can use some paper to mark off specific locations on the bed to ensure that the nozzle is consistently at the same height.
3. Clean the hotend
To clean the hot end, use a wipe or a small towel to remove any residue and make sure it is completely dry. Before you assume it will jam, make sure it doesn't have anything else wrong with it. Be careful to slowly release the tension on your extruder feeder.
4. Set up extruder tension
Turn the screw or screws on your extruder to tighten or loosen the gear grip on the filament. This is a common feature of most extruders. Adjust the tension on the filament by loosening the grip of the extruder's feeder, which is the gear component.
5. Replace the Bowden tube
If the filament movement is being hindered by your Bowden tube or hot end lining, which is often a PTFE tube, it may be necessary to replace it. Check that it is not bent or twisted, though.
6. Reduce retraction
The extruder gear can slip if you retract the filament too much all at once. Then you might want to experiment with decreasing the retraction speed and distance.
7. Adjust printing speed
Alter the printing speed; too slow or too quick can cause striping. Some manufacturers suggest boosting print speed to avoid heat creep and hot end jams as a means to address the former. If you're worried about overworking the extruder, you can try printing at a slower speed for the second option.
8. Do not print at a high speed
Reducing the printing speed is the next logical step to take if filament grinding remains after increasing the temperature. Reduce the torque required of the extruder motor by extruding the filament over a longer duration. Lowering the extruder motor a few notches will stop grinding issues. Navigate to "Edit Process Settings" and select the Speeds tab to modify this value. You can adjust the extruder's active plastic extrusion speed from the "Default Printing Speed" option. Cut the print speed in half if the filament grinding is still there after reducing it from 3600 mm/min (60 mm/s), for example.
Best 3D Printing Software
There are various 3D modeling software available that you can use to create your files and prepare them for 3D printing, and a good example is SelfCAD. It works on Windows and MacOS, and the browser-based version ensures you can work anywhere, anytime. With SelfCAD, you can create files from scratch or edit the existing ones. It comes with interesting tools like freehand drawing and sketching, image to 3D model, powerful 3D sculpting brushes, and easy-to-use selection modes.
In addition to 3D modeling tools, SelfCAD also comes with an in-built online slicer that you can use to slice your designs and generate the G-code to send to your 3D printer.
Stopping Filament Grinding in Its Tracks
Filament grinding happens when the extruder gears of a 3D printer strip away or chew through the filament instead of pushing it through the nozzle. This usually results in print failures because the filament can’t feed properly anymore. If filament grinding isn’t fixed, it can lead to under-extrusion, failed prints, or even extruder damage. So, if you hear clicking noises or see filament dust near the extruder, it’s time to troubleshoot! Your chances of solving or preventing this issue will be much improved if you follow these solutions and investigate the causes. There are other potential causes as well, so be on the lookout for unusual issues.
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