Very often, the X axis rods come loose during shipping. This can create problems with layer alignment as the rods slide back and forth during printing.
- Turn the printer around so you have access to the back of the printer.
- Raise the X gantry all the way to the top by manually turning both Z axis lead screws.
- Remove one of the screws holding the belt on to release the belt tension.
- Loosen the set screws holding the X axis rods on each side (use the smallest hex wrench that came with the printer).
- Center the X axis rods so an equal amount extends through the block on each side. Tighten the set screws as tight as you can without stripping the head of the set screws. [TIP: You can replace the small set screws with standard M3 screws with larger heads that are less likely to strip when tightened.]
- Re-attach the belt. Ensure the extruder travels smoothly from side to side and the X axis rods are solidly locked in place.
- Power on the printer, home, and re-level the bed.