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roo

Skewed/leaning Prints

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Hello,

 

I have an Ultimaker 1 that has been relatively trouble free until suddenly I'm getting skewed/leaning prints.

 

 

lean1

 

I spotted a loose pulley and tightened that up (but I think it was on an axis not relevant to this problem)... I can't see any other loose pulleys.

 

Any ideas what might be causing it?

This image shows the orientation of the lean on the Ultimaker.. X Axis?

lean3

 

Cheers

- Roo

 

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This is a common problem. When it leans like this it means it is *not* a loose pulley. It means something is rubbing. With the steppers off (for example power off is one way to do it) push the head around and see if friction is different in X versus Y.

The problem is X and most likely you won't feel any difference. Usually it's the X motor and belt in the back right corner of that picture you took. The belt is probably rubbing the wood. So lower the bed, remove the X stepper, place it on the bed (so you don't stress the wiring too much), loosen the pulley and try to slide it closer to the motor if you can - you want the tiniest possible gap but big enough that it doesn't touch the stepper.

Alternatively if this gap is well under 1mm you can instead add 1 washer under each of the 4 pastic standoffs. This will move the motor (and pulley and belt) farther from the wood.

 

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I have had this too, before. Like gr5 said, it is a rubbing/friction issue.

Be sure to oil your rods from time to time. I always have a tube of oil besides my UM.

I am a bit paranoid, but I oil the rods every 3 hours or so...

 

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Thanks a lot both I've tried some silicone spray on the rods (this OK since there is apparently a self-lubricating bearing?) and I've moved both stepper pulleys away from the frame. There was definite rubbing since there were marks where the bands had rubbed on the wooden frame. I'm just reprinting the piece posted above so I'll let you know how I get on.

Thanks again

- Roo

 

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So here's the same piece after adjusting the pulleys and although it is definitely better it's still skewed.

lean post adjustment 1

This is a shot of the belt post-adjustment. It's still close, but definitely not touching as far as I can see now.

There is one thing of note that happens to the belt during printing and I have recorded a video of it here:

 

As the motor's direction changes the belt twists, is it possible that this could be causing excess friction?

Any other suggestions?

Cheers

- Roo

 

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I can't see you video, as I only have a bad internet connection today, due to an ice storm. But, yes, it sounds liek that could be a problem. You need to make sure that all the pulleys are properly lined up, so that all the belts run smoothly, and don't twist or catch on the sides of the pulleys.

 

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As the motor's direction changes the belt twists, is it possible that this could be causing excess friction?

 

Yes! That's it exactly! I had the same problem on my UM1. Add 4 washers under the motor spacers. One washer for each spacer. Afterwards you will get both:

1) No more lean/skew

2) No more twist when changing directions.

 

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