Top Layer Moves out of align, Please advise

Hi
Two Of my failed prints because while printing suddenly the printer start to print approximately 1mm from the edge on the y axis plain.
The left and right side layers are aligned however the back & front edges are not aligned by about 1mm.
Its like the piece move forward but it did not move at all because the piece is firmly stuck to the bed.

I checked the Y axis belt , it seems fine.

Can you give me an indication where I can fault find.

Thanks

Check your acceleration and jerk settings in the firmware. If they are too high it can cause that sort of shifting, especially if the bed moves in the Y axis (higher moving mass- problems show up here first).

Mine was doing that when I first started out. On the advice of others I began lowering my XY Jerk value in Configuration.h and after going from 20 all the way down to 10 it finally stopped (after many many prints it's never done that again). I also lowered the acceleration rate from 3000 to 2000 and the printer just sounds much better than when I first got it up and running. It is one of the cheap I3's from EBay and for a first printer to learn on, has served me well.

I would measure the Vref for the y-driver first. If it is still low and the stepper gets only barely warm, I would increase the Vref .

I don´t know, how the firmware interprets the acceleration value. Does it also work as deceleration before the end of a trace?
-Olaf

Yes, acceleration and deceleration. You can check it by setting it to a ridiculously low value and running the printer.

Edited 1 time(s). Last edit at 06/12/2015 10:11AM by the_digital_dentist.