Inexplicable X-axis belt twisting

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peter.p13

(@peter-p13)

New Member

Inexplicable X-axis belt twisting

I have observed that X-axis belt on my (kit) Prusa i3 MK2S is twisting depending on which way it is moving. The movement seems to originate in pulley on the other side of X motor, but I have no idea why. The pulley itself just rotates and does not wiggle. The belt itself is tight and there is no twisting motion on the left (motor) side.

I captured a video of this: https://gfycat.com/gifs/detail/FailingWatchfulBellsnake
Some other photos: https://imgur.com/gallery/8RjQQ

It is very possible that I assembled something wrong, but I cannot think of what that might be.

My questions are:
1. Should I be worried about this? (Perhaps it is normal and does not affect printing)
2. What initiates the belt twisting?
3. How can I fix it?

Thank you for any info.

Posted : 17/09/2017 10:15 pm

AJS

(@ajs)

Noble Member

Re: Inexplicable X-axis belt twisting

http://shop.prusa3d.com/forum/original-prusa-i3-mk2-f23/belt-rubbing-on-x-axis-t1232.html

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 17/09/2017 10:53 pm

peter.p13

(@peter-p13)

New Member

Topic starter answered:

Re: Inexplicable X-axis belt twisting

http://shop.prusa3d.com/forum/original-prusa-i3-mk2-f23/belt-rubbing-on-x-axis-t1232.html

Thanks, it does seem that the belt is touching the pulley sides, I'll try to center it somehow.

Posted : 18/09/2017 9:17 am

harryg

(@harryg)

Active Member

Re: Inexplicable X-axis belt twisting

I have modified the x-carriage on my MK2S to allow belt adjustment for the rubbing issue.
I raised the parts that hold the belt by 4mm.
Here is the link: https://www.thingiverse.com/thing:2541730

Posted : 19/09/2017 1:41 am

Iancun

(@iancun)

Eminent Member

Re: Inexplicable X-axis belt twisting

I have the exact same problem - the printer prints fine, but I get the belt twisting at the idler side. It doesn't appear to be rubbing in the place that the updated model shows, could there be another cause for this?

Posted : 26/09/2017 4:20 pm

henrik.w

(@henrik-w)

Estimable Member

Re: Inexplicable X-axis belt twisting

Could it be that the belt is ever so slightly misaligned when watching a straight line from the one side of the belt (x-stepper motor) to the other side (x-idler) compared to where the ends of the gt2 belt is anchored - see picture?

The forces (F) pulling the belt will then probably be slightly in a cross formation instead of a optimal straight line and thus the belt will be twisting.

/Henrik