Leaning:
A leaning print is usually caused by friction causing the print head to move a shorter distance than expected. Make sure that the short belts that connect the stepper motors to the axes do not rub up against the main body of the printer. Similarly make sure that the pulleys on the stepper motors that the belts ride over are not touching the side of the printer. If they are you must move the pulley closer to the stepper motor.
It is difficult to reach the set screws that secure the pulley to the motor and you will therefore have to remove the white cover plates that the motors sit behind. These panels are held in place with a single screw on the side of the machine if you have a slightly older printer. On the newer ones there are two screws, one on the back and one on the side. Remove the screw and then lift the covers off by tilting the cover slightly towards the front and them lifting them out. The only thing holding them in place is a small metal tab at the bottom of the cover that sticks down into the bottom of the printer.
On the Go there are no screws to remove. Instead the covers are held in place with small tabs that stick into the walls of the printer and into the bottom. These covers require a little bit of brute force to remove. Try pushing in the areas marked in the picture below and then pull the cover to the left. You'll likely have to wiggle the cover around a bit to get it loose. As you might imagine getting the covers back on can be a bit of a challenge but with some patience and finesse they'll snap back into place.
Now you will be able to reach the set screws of the pulleys. If you can't reach the screws easily simply move the head around so that they rotate into view. Undo the screw a turn or so and then push the pulley closer to the stepper motor. The pulley should be as close as possible without touching the stepper motor. Don't forget to re-tighten the screws when you are done and make sure they are very tight so that the pulleys cannot slip.
Shifted layers:
If the printer suddenly shifts the layers it is most likely that one or more pulleys are not secured properly to the axis/axes. To confirm that this is the case you can use a black marker and put marks on the pulleys and a matching mark on the axes. After printing a test print and seeing a layer shift you can then inspect your marks and see which pulley(s) have moved. It is likely that the pulley(s) that need tightening are those connected to the short belts. Tighten the set screws that hold the pulleys in place very tightly, probably a bit tighter than you expect. The small allen key that came with your printer will flex as you tighten the screws. Don't forget to check the pullies that are attached directly to the motor shaft, you can read about those in the section above.
Try to move the head around manually with the power turned off. The head should move around quite easily and there should be similar resistance in both the X and Y direction. If the head is moving stiffly it is probably a good idea to give the rods a drop of light machine oil each (such as sewing machine oil).
Another cause for stiff movement can be misalignment of the rods so that they are not perfectly square. Check this by moving the head to the left/right side of the machine and checking that the distance between the sliding blocks and the pulleys are equal on both sides and then repeat for the front/back of the printer. If you notice that the axes aren't square you can fix this by loosening the set screws on the two pulleys of one rod so that the sliding block on that side can move without affecting the opposing block. Nudge the block the needed amount and then re-tighten the set screws.
It could also be that the part you are printing detached from the platform during the print. This should be fairly easy to see as the part will have shifted position from where it was originally.
Make sure that your glass plate is held firmly in place. If the clips aren't gripping the plate firmly enough it might shift slightly during the print. If they are too loose you can use a pair of pliers to gently squeeze the clips together.
In rare cases there could be an issue with end stops triggering unexpectedly due to cross talk between wires. Re-routing the cables can help with this. But again, this is a very rare occurrence.
Yet another, even more rare, cause can be overheating stepper drivers. A design change of the traces on the mainboard can lead to more current than expected to get to the stepper drivers. This causes the stepper motor to overheat which in turn kicks in the overheating protection in the driver. As the stepper overheats it shuts off for a fraction of a section to cool down and this is when the shift occurs.
You can check/fix this issue by lowering the amount of current for the x/Y steppers in the settings of the printer. Go to Maintenance -> Advanced -> Motion settings -> Current X-Y and set it to 1200mA and then attempt a new print.
Tag:
3D Printers User Guide
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