Layer Shifting

Most 3D printers operate using an open-loop control system. Essentially, this means they don’t have feedback on the actual position of the toolhead. The printer sends instructions to move the tool head to a specific location and assumes it reaches that point. In most cases, this works well because the stepper motors that control the movement are quite powerful, and there’s little resistance. However, the printer can’t detect an issue if something goes wrong. For instance, if the printer is accidentally bumped while printing, the tool head might shift to a different position. Since the machine doesn't have feedback to recognise this, it will continue printing as if everything is normal. If you notice misaligned layers in your print, it’s often due to one of the following causes. Unfortunately, once this error occurs, the printer can’t detect or fix it, so we’ll cover ways to prevent and resolve these issues below.

Common Causes and Solutions:

Toolhead Moving Too Fast

The motors may struggle to keep up if the printer moves too quickly. When the printer moves faster than the motors can handle, you’ll often hear a clicking noise, which is the motor failing to reach the intended position. This results in misaligned layers for the rest of the print. If you suspect the printer is moving too fast, try reducing the speed by 50% to see if it helps. You’ll want to modify the “Default Printing Speed” and the “X/Y Axis Movement Speed.” The default printing speed controls movements when the extruder is actively printing, while the X/Y axis movement speed governs rapid movements where no plastic is being extruded. If either speed is too high, layer shifting can occur. For those familiar with advanced settings, you may also consider lowering the acceleration settings in your printer's firmware to allow for smoother starts and stops.

Mechanical or Electrical Issues

If reducing the print speed doesn’t solve the problem, it may be caused by mechanical or electrical issues. Many 3D printers use belts to control the position of the toolhead. These belts, often made of rubber and reinforced with fibres, can stretch over time, affecting their tension. If the belt is too loose, it may slip on the drive pulley, meaning the motor turns, but the belt doesn’t move. Conversely, if the belt is too tight, it can create excessive friction in the bearings, preventing the motors from rotating properly. Check that your belts are neither loose nor tight and adjust as needed. Consult your printer’s manual for guidance on adjusting belt tension if required.

Another common mechanical issue involves set screws (also called grub screws) that attach pulleys to the stepper motor shafts. If a set screw loosens, the pulley will no longer spin with the motor, even though the motor itself is rotating. This prevents the toolhead from reaching its intended position, causing layer misalignment. If layer shifting occurs frequently, ensure that all motor fasteners are securely tightened.

On the electrical side, insufficient current to the motors can also cause them to lose their position. If the motor driver electronics overheat, the motors may temporarily stop until the electronics cool down, leading to misalignment. This highlights the importance of monitoring both mechanical and electrical components when troubleshooting persistent layer shifting.