Prints 'Slide' on the Y-Axis (Front-Back)

[darthrith 0]

Hi guys! Just got my Ultimaker about 2 weeks ago, made good progress tweaking and getting it running, now it prints decent stuff!

However there is just ONE problem plaguing me, and has been for a week. I'll let 2 photos show you what it is.

As you can see the X-Axis (Left-Right) is nice and straight, while....

The Y-Axis is slanting and simply doesn't stay straight! This is the most recent test, it was previously slanting towards the front, and now slants to the back after some tweaking.

I've already tried :

1) Adding tension to both Y-Axis belts using a belt tensioner

2) Checking pulleys for any sliding

3) Lubricating all the axes

Also, is this what they call a backlash? Are there any other ways I can fix this?

[Daid 306]

Did you check the small belt tension?

[mr_seeker 0]

Try loosening the motors, then put pressure on them while retightening the bolts. This should tighten the small belts and keep tension on them.

[joergen 2]

small belt tension is important... my Y motor screws cam loose, and the print looked real raggedy... tightened the belt while printing :-)

But I had replaced my steppers last year, and never adjusted the pots on the stepper driver to the larger motors, and the current for the Y was a bit too low, which added to some tiny Y misalignments... adjusting the pot too much (1/16 of a turn) was letting the motor run too hot, and it jumped/offset 10mm in Y... I would see how hot you stepper is... if it's just luke warm, adjust the current up, if it's warmer than unbearably hot after 15 sec testing with your finger (about 65-70C in my case), turn down the pot a hair. that solved the misalignments in my case.

[darthrith 0]

Thanks guys, the advice absolutely helped. Fortunately I didn't have to mess with the pots!

So to sum it up,

If your prints are getting misaligned/slanting towards a certain direction (left-right/front-back) check the respective motors for the following :

1) Pulley connected to the motor must not be grinding against each other, mine even has some residue due to the 2 surfaces grinding. Not good. Loosen the pulley, leave a gap between the pulley and the motor, re-tighten the pulley.

2) Loosen the motor, apply some pressure to push it downwards and re-tighten the screws. This gives the short timing belt more tension.

Thanks again for your input guys, much appreciated.