Y offsets while printing.  

RE: Y offsets while printing.

Check your pulley grub screw on that axis isn’t loose. It’s the usual cause of small layer shifts. They have to be done precisely according to instructions or they will loosen over time. 

RE: Y offsets while printing.

Hi John, 
Typically, if a printer offsets in a particular direction, and then resets, in a fairly random manner, by the same amount, it is usually due to the  Motor pulley on the relevant axis motor spindle, not being secured properly. 

there are two Grub screws on the motor pulley, 

One screw should be tightly fastened against the flat on the motor spindle, the other should be fastened tightly against the curved part of the motor shaft. 

If these screws are a little loose, the motor shaft turns within the pulley, until it jams the loose grub screw against the flat on the motor spindle, off centre... 
the motor  shaft will generally remain jammed, until there is a higher than normal resistance to movement, in the opposite direction at which point the motor shaft will rotate inside the pulley, until the grub screw jams at the other side of the flat on the motor spindle. 

this action will produce relatively uniform offsets because the total travel is restricted by the degree of slackness in the grub screw... 

another issue can be collisions caused by poorly lubricated bearings (jamming and not resetting to the virtual endstop properly), but this tends to cause less regular offsets. 

regards Joan

RE: Y offsets while printing.

Thanks I'll try that. I bought it pre assembled so Ive got to do some investigating. thanks john