[BUG REPORT] Uneven vertical prints

Support for UP mini. To report a bug, post with a title [BUG REPORT]. To request a feature, post with a title [FEATURE REQUEST]
Post Reply
tacticali
Posts: 6
Joined: Mon Apr 01, 2013 5:07 am

[BUG REPORT] Uneven vertical prints

Post by tacticali » Mon Apr 01, 2013 5:42 am

My Up! Mini is printing misaligned vertical walls.
As you can see, the distortions are repeated every 9 or so layers ( about 2mm ).
The problem gets worse when printing further away from the center.

Each of the below was printed at 0.20mm layers, on fine resolution.

Links to the STL's printed:
Battery case ( white print ) : http://www.thingiverse.com/thing:68332
Dinosaur ( green :) ) http://www.thingiverse.com/thing:13538

Any help would be appreciated :)
closeup.jpg
closeup.jpg (148.54 KiB) Viewed 10685 times
small_1.jpg
small_1.jpg (168.03 KiB) Viewed 10685 times
small_2.jpg
small_2.jpg (200.95 KiB) Viewed 10685 times

marto
Posts: 87
Joined: Wed Nov 14, 2012 2:01 pm

Re: [BUG REPORT] Uneven vertical prints

Post by marto » Thu Apr 04, 2013 4:07 pm

Have a look and see if this is the same pitch as the lead screw on the Z axis. If the screw is bent it can put pressure on the plate moving it slightly left or right as it moves up layers.

This could have happened in transport. Would suggest warranty claim.

Steve

tacticali
Posts: 6
Joined: Mon Apr 01, 2013 5:07 am

Re: [BUG REPORT] Uneven vertical prints

Post by tacticali » Fri Apr 05, 2013 11:36 am

Thanks Steve, but my mini doesn't have any lead screws - it's all pulley driven.
As far as I can tell, the guide rods all seem pretty straight as well.

marto
Posts: 87
Joined: Wed Nov 14, 2012 2:01 pm

Re: [BUG REPORT] Uneven vertical prints

Post by marto » Sat Apr 06, 2013 1:33 am

Should sleep more before posting.

Mini doesn't even have lead screw. Which leads me to think of bent motor shafts.

Check that.

Steve

tacticali
Posts: 6
Joined: Mon Apr 01, 2013 5:07 am

Re: [BUG REPORT] Uneven vertical prints

Post by tacticali » Sat Apr 06, 2013 3:38 am

Thanks Steve,
I'll look into the motor shafts.

I've previously looked at the guide rods, and they all seem straight enough to me.

mr6k
Posts: 327
Joined: Tue Feb 14, 2012 11:47 am

Re: [BUG REPORT] Uneven vertical prints

Post by mr6k » Sat Apr 06, 2013 9:21 am

Looking at the dino image, difficult to tell exactly, but it looks as though the error is sizing not shift. Both the left end and right end seem to have layers "sticking out" at the the same horizontal plane. If so it would not a bent shaft but some stepper error. Looking at same image it also seems to be in both X & Y plane. If this is the case I would say that for some reason the extruder is putting out more material on some layers than others. Therefore where more is put out it squeezes across the surface more than when putting out less material. Conversely the same extruder rate is occuring but the Z axis is moving vertically at greater or lesser rates, this would have a similar effect. As it is so regular could be a stepper pulse missing, does it repeat at some multiple of x2 or x4 layers? I suppose it could be a bent Z axis stepper motor shaft.

cheers

Peter

tacticali
Posts: 6
Joined: Mon Apr 01, 2013 5:07 am

Re: [BUG REPORT] Uneven vertical prints

Post by tacticali » Wed Apr 10, 2013 11:03 am

Thanks Peter

I've looked at the motor shafts on all axes.
Given their short length, It's difficult to tell if there's any deflection, but they all seem straight, and 90 degrees to the motor face / mounting.

The pattern seems to repeat between the amplitude peaks.
8 layers, then 6, then 8, then 6 ( or there abouts ).

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: [BUG REPORT] Uneven vertical prints

Post by roller » Thu Apr 11, 2013 9:11 am

If you print at a different layer height does the deflection pattern change or does it remain the same?

User avatar
wackojacko
Posts: 667
Joined: Fri Nov 12, 2010 5:46 am
Contact:

Re: [BUG REPORT] Uneven vertical prints

Post by wackojacko » Thu Apr 11, 2013 10:05 am

What I would do is switch the z stepper motor with the x stepper and see if the issue changes axis, I just fixed one like this.
Bruce
http://www.3DPrintingSystems.com

Need help with your printer, check out our Youtube channel.
https://www.youtube.com/user/3dprinting ... /playlists

tacticali
Posts: 6
Joined: Mon Apr 01, 2013 5:07 am

Re: [BUG REPORT] Uneven vertical prints

Post by tacticali » Sun Apr 21, 2013 2:50 am

Thanks for your suggestions everyone.

I switched the z and x motors - here are some photos of resulting prints.
DSC_8105_50.jpg
closeup2
DSC_8105_50.jpg (201.16 KiB) Viewed 10452 times
DSC_8107_40.jpg
closeup1
DSC_8107_40.jpg (244.03 KiB) Viewed 10452 times

The distortion is still there, but it now resembles a saw-tooth pattern, rather then a sine wave.
It is also now quite clear to see that the entire layer is skewed, rather then a sizing issue ( suggested by mr6k ).

I've done quite a few different prints, at different z resolutions, and the issue persists regardless.

I have noticed that the skewing seems to happen towards the front right corner ( thus, away from the rear left corner ).

Aside from this, I'm very happy with the little printer - but it is starting to effect more complex, mechanical prints where accuracy is vital ( like http://www.thingiverse.com/thing:53451).

Is this something that I should take up with my vendor?

Thanks.

User avatar
wackojacko
Posts: 667
Joined: Fri Nov 12, 2010 5:46 am
Contact:

Re: [BUG REPORT] Uneven vertical prints

Post by wackojacko » Mon Apr 22, 2013 9:55 am

Can you do a side by side comparison also indicate which axis is z x y in each photo
Bruce
http://www.3DPrintingSystems.com

Need help with your printer, check out our Youtube channel.
https://www.youtube.com/user/3dprinting ... /playlists

Post Reply