X Axis slips after first layer prusia I3 pro

My I3 starts to jump on the X Axis always after the first layer, I have checked and changed belt tensions, put a new stepper motor and fixed a fan to the motor to keep it cool. I have noticed that when the belt is moving it looks like it loosens when it starts to move, but it does that even if the belt is tight, even with the belt at its tightest and forcing the motor for a short while it tents to slip. I don't know if an XAXIS jumping has anything to do with the Z Axis, it comes to mind coz it's as I said always after the first layer..thanks for any help its been driving me mad...

Did you check that the grub screws on the pulley are tightened?

The pulley's not slipping on the motor shaft is it?

Maybe keep an eye on it while it's printing. You might find its slipping.
It might not be as apparent if the first layer is being printed slowly.

Edited 1 time(s). Last edit at 01/09/2017 03:58PM by FA-MAS.