Troubleshooting

Error

Cause(s)

Solution

Warping:

The print detaches from the heating bed and bends.

The print should actually lie flat on the bed, but it has become partially detached and bent. In this case, PETG was used for printing, which came loose due to the bed temperature being too low.

The filament contracts as it cools, causing the print to lose adhesion and change shape slightly.

Incorrectly leveled bed, or too large a distance between nozzle and bed.

• Reduce the distance between the bed and the nozzle
• Increase the heating bed temperature
• Clean the heating bed (especially grease residues from fingerprints can be a problem)
• Switch off the print cooling option in the slicer
• Use the printer in a well-heated room
• Change the print substrate (e.g., Blue Scotch tape)

Note: Wrapping cannot be avoided with ABS. Ideally, the room around the printer should have the same temperature as the print bed itself.

Important for newcomers: It is not enough to adjust all 4 bed level screws on a sheet of A4 paper, as all corners of the bed change their height with each adjustment. The following procedure guarantees a well-leveled bed:

1. Adjust all 4 corners in sequence (front left, front right, back right, back left; distance between nozzle and bed should be approx. one sheet of paper thick (thick printer paper, not block paper)
2. Adjust corners diagonally (front left, back right, back left, front right)
3. Check the distance in the middle of the bed; if necessary, adjust all 4 screws evenly.

The nozzle must not touch the bed when it is pulled from corner to corner. If the print bed is bent (e.g., slightly dent), the printer should be adjusted so that the distance between the nozzle and the bed at least fits in the middle. With larger prints that reach into the corners, the distance may be too large or too small. The bed must also have no play (with the Ender 3, this can be remedied by tightening the concentric nut that presses the bed rollers into the aluminum guide (do not overtighten!).

Skipped Layers:

The walls of the model are not even (omitted layers or thicker layers).

Here, the Z axis was not raised enough, and the new layer was printed into the previous one, resulting in a thicker layer and an unsightly line in the print.

The Z-axis does not always lift by the set layer thickness.

• Cleaning the Z-axis threaded rod
• Adjust the screws on the coupling between the Z-stepper motor and the threaded rod (the threaded rod must not slip in the coupling and must not be crooked)
• Check the attachment of the Z-axis motor (the motor must be firmly attached to the frame and must not be crooked)
• Oil/grease the rod

Note: on some printers (e.g. Ender 3) there are two screws on the suspension, which runs in the threaded rod, which regulate the pressure on the threaded rod. These should be neither too tight nor too loose and must be adjusted by feel. An omitted layer can also be an indication of under-extrusion, see below.

Stringing:

The print head pulls threads when it makes an empty run.

The filament in the nozzle continues to expand due to the heating and thus pulls threads even if the extruder does not feed new filament.

• activate the Retraction option in the slicer (retracts the filament before an empty run)
• increase the retraction distance (4-5mm)
• Reduce the print temperature slightly (~5°C), but do not go below the prescribed print temperature!
• Activate Z-Hop (the print head is lifted before an empty run)
• Activate print cooling
• Activate Coasting (possibly only available in CURA, filament flow is stopped shortly before travel but still in the actual print path and thus the last section is printed with filament swelling out)

Note: If the filament has become damp or is of poor quality, this can lead to heavy stringing, which can hardly be avoided.

Under-Extrusion:

Print material is missing in the walls of the print or no material is ejected at all.

(Left: Print with slipping extruder gear, Right: Print with new stainless steel extruder gear, nothing was changed except the extruder gear)

Here the filament supply was disturbed during printing by small particles clogging the nose. However, the problem resolved itself due to the built-up pressure and the heat. This can be avoided with a filament filter.

The printer is unable to consistently dispense the correct amount of filament. This can have several causes such as a clogged nozzle, poorly wound filament or a dirty extruder gear.

Note: one of our Ender 3 was delivered with a blunt extruder gear which had to be replaced by a stainless steel extruder gear from Amazon. When purchasing, make sure that the new gear has the correct dimensions (inner & outer diameter) and also has 2 grub screws (one engages in the groove of the stepper motor shaft and the other serves to secure against vibrations)

Caution when printing with FLEX/TPU filament: Due to the bendability/compressibility of the filament, a loop may form directly after the extruder gear or the filament may be stretched or crushed and no further filament is fed into the hotend.Bowden extruder systems are particularly affected by this.

• Check that the filament is unwinding smoothly
• Clean the extruder gear wheel if it slips on the filament thread, blunt extruder gear wheels must be replaced!
• Clean the printer nose: if small dust particles accumulate in the nozzle and block the flow, there are two ways to clean them:
  
  1. Coldpull: The nozzle is only heated until the filament in the nozzle becomes viscous (100°C for PLA, 120°C for ABS). Now the filament is pulled out of the printer with a strong jerk (make sure that you operate the device for changing the filament and do not damage the printer). There should be small particles of dirt at the end of the filament that has been pulled out. Now cut off the dirty piece and insert the filament back into the printer as normal (heat the nozzle to filament temperature!). Now the nozzle can be cooled down again. This process should be repeated 2-3 times.
  2. Needle: Many printers are supplied with a thin needle to clean the nozzle. Before cleaning, make sure that the nozzle is preheated to filament temperature and that the needle tip is clean.
• In case of problems with FLEX/TPU: Switch off retraction completely, reduce print speed (~30mm/s), switch off print cooling, clean extruder gear, for printers with Direct Drive there are special extruders for FLEX/TPU. Avoid empty run/travel

Note: to prevent clogging of the nozzle, there are filament filters on Thingiverse which can be printed out and use a small sponge to clean the filament of dirt particles as it is drawn into the printer.

Ghosting:

Unwanted patterns or spongy edges and corners can be found in the walls of the print.

The wave-like pattern was created by a high printing speed. The printer vibrates when changing direction and this vibration is projected onto the subsequent walls.

The printer may start to vibrate due to jerky changes in direction and therefore no longer print clear lines. This may be due to a loose base, loose frame screws or poorly tensioned tension belts, for example.

• Check the printer for stability, the printer must not move if you wiggle it, this also applies to its base (e.g., shelf or table)
• Check the tension rubber bands of the X and Y axis for tightness
• Check the ease of movement of the bed and the print head
• Reduce print speed and print acceleration (in the slicer)
• Check printer frame for play and tighten screws if necessary

Note: FDM printers can never print completely vibration-free due to the nature of their materials, but vibrations can be reduced to such an extent that they are no longer perceptible to the eye.