Lopsided/Skewed Prints

[djproductdesign 0]

Hi guys, I have been trying to print a number of objects on the Ultimaker and have been running into some lopsided and skewed print problems. They are always in the negative x direction. (see pics below)

The first two images show how the print tilts to one side. The third image shows how the layers have been shifted over by about 1mm. These I believe are two separate problems that don't appear to occur at the same time.

I have updated the firmware and calibrated the machine several times. Some of the prints come out fine but the majority have been problematic.

The files are fine, there are no issues I can see on Cura, even when I check the tool path, everything looks great.

If anyone has a solution or is experiencing something similar it would be great to chat and/or hear about how this can be resolved.

If you need any more info please let me know.

Thank you.

 

[illuminarti 18]

This is probably due to a pulley that is slipping slightly in your X drive system. Check that all of the pulleys are really tightly screwed to their axes. You may want to use a permanent marker to make a mark on each pulley and its shaft, and make sure those marks are still lined up at the end of the print.

I believe that UM ships spare screws for the pulleys, in case the ones that are in already prove to be defective - so if you have problems getting a pulley to stay in place, you may want to swap out the screw.

Most likely the problem is the pulley on the motor itself, or the one on the other end of the short belt, as those are the ones that experience the greatest forces.

Also check that the short belts aren't rubbing on the frame.

 

[gr5 2,004]

Illuminarti speaks truth. This is a very common problem with a new UM.

 

Also check that the short belts aren't rubbing on the frame.

 

This is easy to diagnose because as it is printing you can see the belt twisting one way then the other. Fix this by adding washers under the plastic standoffs and possibly (if necessary) move the pulley even closer to the motor. It should be as close as possible without touching the stepper. Around 1/2 mm is good.

It's either this or loose set screws. Tighten all 6 (if you only found 4 keep looking!) on the X axis. Tighten the hell out of them.

 

[djproductdesign 0]

Thank you so much for your input Illuminarti and gr5. This solved the problem, I've tightened the screws as there were none other to replace them with. I have marked the shaft and pulley so that I can see any slippage in future.

And again, many thanks!

Dan

 

[mygoal 0]

I read the post “Lopsided/Skewed Prints” by djproductdesign because I have the same kind of problem.

So again I tightened every screw I could find and checked that the short belts aren't rubbing on the frame, just like Illuminarti and gr5 suggested.

But without any possitive results.

The problem appeared all of a sudden and first look to have been gone but now it's even worse.

The firts models where perfect.

– For the firsttime it's slightly visable at the Owls but I didn't took a note of that because after that I printed some blocks which where okay.

– Than the Mont Saint-Michel became like a dream-print.

It looks like it came back to it's original point, which I think is a bit different that djproductdesign had.

After this I printed again some blocks (10x10x10mm) and again these looked fine.

– So I imported a drawing with some more geometrie but this went terrible wrong.

– From that moment everything is printed skewed; the blocks, the Ultimaker-logo-robot...

check http://umforum.ultimaker.com/index.php?/gallery/album/152-problems-skewed-prints/ for pictures

 

[mygoal 0]

I just checked everything again...

Reassembled parts, losen every screw and tightened it again...

And now everything looks doing well...

Hope it was the same problem!

 

[gr5 2,004]

I recommend you mark the pulleys with a sharpie (permanent marker) so you can tell if something is slipping.

I hope you realize if only one axis is slipping then you only have to fix one axis (X or Y).

 

[uq6 0]

Thanks!  This post reminded me to check the physical stuff, not just the many layers of configuration.  Sure  enough, the X stepper motor itself was lose.  Prints are much better now!  (In my case, the skewing only occurred late in prints.  There must be more resistance on the nozzle once the model is higher.)

[kmanstudios 1,120]

37 minutes ago, uq6 said:

Thanks!  This post reminded me to check the physical stuff, not just the many layers of configuration.  Sure  enough, the X stepper motor itself was lose.  Prints are much better now!  (In my case, the skewing only occurred late in prints.  There must be more resistance on the nozzle once the model is higher.)

Repositories are nice, eh?