What Is It?
Layer shifting is one of the most undesirable problems in 3D printing, and there's no way to recover your prints from this issue. A layer shift is unpredictable, not easy to diagnose, and leads to a print failure. Layer shifts are more likely to occur during long printing jobs due to the continuous strain on the printer's mechanical and electrical components.
The best way to prevent layer shifting is to perform periodic maintenance of your printer and ensure that each component performs optimally.
Alternatively, if your prints fail due to the layer shifts, you can use Obico to quickly catch the failed prints and stop it. The Obico software offers you complete remote control of your 3D printer, and helps you save on filament and printing time.
What to Check?
- Print speed
- Belt tightness
- Mechanical assembly
- Stepper motor temperature
How to Fix It?
Lower the Print Speed
When printing at high speeds, the stepper motor, and your printer's controller work overtime to execute the gcode commands. A low-end controller or a stepper motor increases the chances of missing a step, thereby resulting in a layer shift.
It's not always the case, but it is one of the probable reasons behind layer shifting. Moreover, high printing speeds cause your stepper motors to heat and affect the print quality. Therefore, it's better to print at relatively slow speeds of around 60-80 mm/s (depending on your particular printer) than to have fast printing speeds, which might result in a print failure.
Adjust the Belt tension
An improperly tensioned belt is one of the most common reasons behind layer shifts. If your belt is too loose, there's more slack in the belts, causing the print head and bed to move freely. In contrast, if the belts are too tight, they might temporarily slip from the pulleys, disturbing the printer's movement but resulting in a layer shift.
It's challenging to set the belt tension perfectly for every printer. Usually, you should set the belt's tension to be similar to a guitar string. A properly tensioned carriage will have a smooth movement, and you should be able to move freely without noticing any bumps or jerks in its motion. You can also install a belt tensioner on your printer, manually adjust your belt tension and ensure it's always at the right setting.
Calibrate the Stepper Motor Driver Current
If you're noticing frequent layer shifts or your stepper motor is too hot to touch, you might have an improperly calibrated stepper motor driver. A high current value will cause your motor to run hot but also increase the motor's torque. In contrast, if your supplied current is too low, it will result in a cool stepper motor but with less torque.
Yet, you need an optimally calibrated stepper motor that doesn't run too hot but has enough torque to carry your print head and the bed. It's quite an elaborate process to calibrate and set an ideal stepper motor current for your 3D printer. You can refer to a detailed guide from Teaching Tech on this issue and set the suitable stepper motor current for your printer.
You can use a stepper motor heat sink to keep your motors within their optimal temperature range during long 3D prints. It might also help to reduce the whining noise of your stepper motors to a certain degree.
Lines on your Print's Surface
What Is It?
Any vertical or horizontal lines on your prints' outer surface are collectively called as Z-line artifacts. These lines include any irregularities visible on your entire print surface in the Z-direction. Ringing or Ghosting and Z-banding or Z-wobble are the common types of artifacts that occur on the print's surface. These affect the print quality and appearance and can lead to interference issues with mating parts.
The primary reasons for ringing and Z-banding printing are the lead screw on the Z-axis. But, sometimes, high printing speed and improper extrusion settings can lead to these issues.
What to Check?
- Lead Screw straightness
- Z-axis assembly
- Printing speeds (for ringing and ghosting)
- Printing Temp and Bed Temp
- Layer height settings (Magic numbers)
- Filament quality
How to Fix It?
Fix the Z-axis assembly
The Z-axis is often incorrectly assembled in budget 3D printers or with printers that require manual assembly. Sometimes the lead screw might not be straight, while the coupling might be broken other times.
In any case, you need to ensure that the Z-axis is perfectly parallel to the printer's vertical components and there are no broken parts in the assembly. The lead screw should be correctly inserted in the Z-motor coupling, and you must ensure it's adequately tight and does not move on its own.
Occasionally, you can lube the Z-axis to ensure there's less friction between the Z-nut and the lead screw, and it moves freely. But, if the lead screw is damaged, it's best to replace it entirely and buy a new Z-axis rod.
Ensure Consistent Printing Temperatures (PID Settings)
Fluctuating temperatures of the hot end and the print bed result in inconsistent extrusions, causing Z-bands on your print's surface. It's crucial to verify the printing temperature range and their periodic fluctuations.
If you notice vast fluctuations in the printing temperatures within a short period, it indicates an issue with your printer's PID calibrations. PID is a kind of control method your printer uses to control and sustain your printing temperatures.
It's relatively easy to calibrate the hot end and print the bed's PID settings, and Teaching Tech has explained the entire process neatly in their detailed PID auto-tune guide.
You should tune your PID settings whenever you change your hot end, cooling fan, bed surface, or other components directly related to the printer's heated components.
Use Correct Layer Heights
The layer height you use with your printer should correspond to your lead screw's pitch. The optimal layer height for your printer is called the Magic Number in 3D printing terminology and can be different for every 3D printer.
There's plenty of debate whether these 'Magic Number' layer heights result in Z-banding issues. But, it's safe to err on the side of caution and fix the issue to rule out any possible factors causing Z-bands in your 3D prints.
Prusa's layer height calculator informs you about the layer heights suitable for your prints based on your printer's lead screw. It's helpful to quickly check the layer heights and adjust them in your slicer settings.
Additionally, you can refer to CHEP's YouTube video, which discusses this issue in detail. It'll help you understand Magic Numbers' concept in 3D printing and apply it in your 3D prints.
Calibrate your Extrusion Settings
Incorrect extrusion settings can lead to inconsistencies in your print's layers and cause Z-bands on your print's surface. Under extrusion can occur due to a clogged nozzle or low print temperature. At the same time, a high filament flow rate and printing temperature are the common reasons behind over extrusion in 3D prints.
There's a helpful guide by Teaching Tech on calibrating your filament flow in slicer settings and ensuring that the hot end has an accurate and even filament flow.
Configure Acceleration and Speed Settings (For ringing and ghosting)
Ringing is caused due to the vibrations that your printer creates when it suddenly changes direction or speed. The vibrations lead to minor imperfect but periodic impressions on your print's surface and are prominent on large, vertical surfaces.
It would be best to print at slightly slower speeds and reduce your printer's acceleration settings. This change will ensure that the print head's direction changes are gradual and slow. It might lead to slightly longer print times, but a slow print speed will help you achieve better print quality.