Every time we try to print something a bit higher we get deformation in the print, in the beginning of the print everything seems perfectly fine but later on it starts to shift. Is there a solution for this problem?
this was supposed to be a mug
i think you printer is scipping steps, did you chec the voltage of your stepper motor drivers?
Yes like Aaron says. I is also possible that your voltages are to high and that the steppers overheat (because of the wrong calibration voltages larger currents will flow) - go into safe mode (skip steps) - cool down - start working again.
It is possibly the calibration voltages on the stepper drives?
Check the voltage on the stepper drivers, maybe it should be slightly increased from the standard 0.425 V.
And, since the problem occurs only after a while of printing, you should check the stepper driver’s temperature.
Thats the Allegro A4988 chip on the four small attached PCBs on the controller board.
Maybe adding a fan and/or small heatsink would help.
Tonight we will check the voltage of the stepper motors. Is it possible this has something to do with a belt?
Skipping a tooth on a belt would be much more noticeably on wouldn’t create such gradual deformations
Yesterday we did some prints, the voltage of the stepper motors are OK. I think the problem is the temperature of the drivers, they become very very hot, can’t touch them. Especially the driver of the x motor. Also the voltage increased from 0.55 to 0.58. We will mount a cooling fan on top of the board to cool.
O and the prints where still deformed after a while (probably when the drivers becomes this hot!)
Driver should not become that hot (they will be hot but should not overheat) maybe because of mechanical stiffness the motors have to push too hard. Check your build and make sure everything moves smoothly.
same problem here… I already started a post, before I noticed this one. Sorry for that.
Can you describe in more detail how hot hot is?!
My drivers become very hot too… actually I can not touch them for more than lets say 5seconds… so the temperature most be somewhat above 65 degrees.
(Compared how long I can touch the bed when it is around 50 degree).
I have no mechanical issues, the drive runs free and smooth… 
Can the movement speed of the printer be misconfigured… so that the software drives faster than the stepper can and therefore skip a step?
you can oil the smooth rods and maybe put a fan in front of the drivers
did nothing to the rods… but put a fan to the drivers… so problem since (but only 3 prints so far…)
well let U known
And do your motors still become hot? I just finished a print of more than 1 hour and my motors are just handwarm … I think really HOT motors, is not good.
It’s not the motors that get hot, it is the driver circuitry on the four small “piggy-back” boards atop the controller that gets hot.
And if it gets too hot, the driver chip shuts itself down, which in turn causes “missed steps” when the controller attempts to drive the stepper motors.
That happened once here, ok. Now without cover, no problem anymore. So your solution with the blower will indeed work.
No problems so far. 
I have to admit: I might have put the current on one motor on “the higher side” (approx 550mV) during calibration.
AND it has become quite hot here in the last week, so there was not much (cooling) ventilation.
I am right know working on a new case/cover with fan mount and also to include the PI with octoprint