How do 3D printer nozzles warm up?

Troubleshooting Feeder digs into filament

The feeder digs in

So that your 3D printer can convey the filament, it has a small drive gear that can grab the filament with its teeth to convey it to the hotend. Usually the filament is clamped between the drive gear and a ball bearing, sometimes also another gear. If this conveying process is disrupted without you noticing, the drive wheel will slip. As a result, a tiny bit of filament breaks off every time. You can recognize this by the abrasion below the feeder and a more or less clear notch in the filament.

Clogged nozzle or hot end

Perhaps the most common reason for grinding is probably a clogged nozzle or a clogged hotend. Please follow the instructions below to check the hotend and nozzle for clogging.

Clogged hotend: First remove the existing filament from your hotend. If necessary, heat the hotend manually beforehand. If your 3D printer has a Bowden system, please also remove the hose to access the hotend directly. Then cut a piece of filament about 20-30 cm long. Now heat your hotend to a temperature that is at the upper end of the processing temperature of your filament, and feed the piece of filament by hand with light pressure. With direct extruders, rotate the feeder forward manually using the printer control.

If necessary, try several forward and backward movements in a row. If no filament comes out, you can try again with the hot end fan deactivated. A piece of filament may be stuck in a place that cannot heat up sufficiently. Repeat the above steps until your hotend is completely free again. If possible, avoid inserting pointed objects into the hotend, you could damage it permanently! If the hotend cannot be exposed with the above description, you can try it last with a fine (!) Needle.

Clogged nozzle: To clean the nozzle, a method that has become known in the community as Atomic Pull has proven its worth. In this process, filament is fed in manually and then removed with jerks, so that residues in the nozzle can be removed. And this is how the Atomic Pull works: Lay out an approx. 20-30 cm long piece of white PLA filament, only this time you will not use the feeder, but feed the filament by hand. With direct extruders, you may have to expose the hotend. Take the piece of filament and heat your hotend to approx. 220-240 ° C. Now slide the filament into the hot hotend.

PLA is particularly suitable because it has suitable temperature ranges and is usually quickly to hand. White PLA because you can see the removed residues particularly well here. But it also works with other white or transparent filaments. Just note that you then have to work with other temperature values. After you have fed the filament manually, material either emerges immediately, but is initially more difficult to move, or a bubble forms and material suddenly emerges shortly afterwards, or nothing (yet) emerges or only a small one forms Bladder.

Do not be discouraged! In the second step you let the material cool down to approx. 85-90 ° C and pull it out with a quick jerk. With 1.75 mm filament, small flat-nose pliers will help to grab the material. Repeat the above steps until your nozzle is completely free again and the filament you have pulled out does not show any black or brown discoloration. Feel free to vary the temperatures mentioned as best suited for your purposes.

The hot end temperature is too low

If the hotend and nozzle are free, your temperature could be too low. Therefore, check the settings of your printing temperature and compare them with the information provided by your filament manufacturer. If necessary, increase the temperature in steps of 5 ° C and observe whether the feeder is now conveying the filament without generating abrasion. Check the temperature not only in your slicer software, but also on your 3D printer. If the values ​​do not match, recreate the gcode and try again. If different values ​​are still displayed, the temperature sensor or the temperature transmitter could be defective.

Printing speed too high

If you were able to rule out all of the aforementioned temperature-related errors, your printing speed may be too fast. Your hotend only has a limited throughput depending on temperature and printing speed. If you try to print at a printing speed that exceeds the capacity of the hotend of your 3D printer, more filament will be pushed in than can emerge at the other end. You can usually recognize this by a clicking sound when the feeder motor loses steps due to the counter pressure. If so, try lowering the print speed and see if the error has been resolved.

Aggressive retreat settings

Check the settings of your filament retraction in your slicer software. If the retraction speed is too high, or the retraction amount is too large, this can be particularly the case with soft filaments, such as. B. TPU or wood-filled filament lead to increased abrasion on the filament. If this happens too often at a certain point in the printing process, the abrasion on the filament can be so great that the feeder can no longer grab the filament. So, especially with soft filament, try a slightly gentler retraction setting and then check if that solves the problem.

Wrong contact pressure on the feeder

Usually the contact pressure of the feeder wheel is already optimally set on your 3D printer. In some cases it may still be necessary to change the contact pressure. If none of the above methods did not help, check out a piece of fed filament. You should see an even but not too strong or too weak impression of your gear. If necessary, vary the contact pressure until you can see an even conveying pattern.