UM2 timing belt question ...

[mnis 11]

Hi

I've noticed that one of the long belt for X / Y-axis is much looser than the other. The belt is, I believe, but still firm enough not to slip.

How can I tighten the timing belt, it is possible, or you need later a new one?

Has anyone had experience with it?

Thanks in advance.

Markus

[gr5 2,071]

The blocks I believe have some kind of tensioner inside but I know of no one who as opened one to see.

Consider loosening the pulley for the "bad" belt and distributing the tension to both top and bottom and then retighten the pulley.

 

[illuminarti 18]

It would be helpful if you could post a vide showing the relative tension of the top and bottom parts. As George mentions, if the tension is uneven, you can just redistribute the tension by loosening and retightening one of the pulleys. Alternatively, if the belt just seems to be too long, then maybe there is a problem with the tensioner. You could just add a UM1-style tensioner to the part of the belt that the sliding block doesn't attach to e.g., the wave tensioner:

http://www.thingiverse.com/thing:19892

Or alternatively attach a spring, like the ones used in clothes pins.

 

[mnis 11]

Great, and thank you both :smile:

It is only a small difference noticeable when it is checked with the fingers and low pressure. I think it's currently not critical. But now I know what to do if it should be worse.

I know the internal structure of the small black boxes with sliding bearings not exact. I had suspected that an adjustment possibility exists, in the interior of these boxes.

Markus

[illuminarti 18]

No, there's no way to adjust the tensioning in the sliding blocks.

 

[gr5 2,071]

The sliding blocks have a spring to keep a constant tension. So if the loose side is where the block is then you can't easily fix it but if the loose side is away from the block then you need to simply loosen a pulley set screw for one second, let it adjust then retighten.

 

[mnis 11]

Well, I'll try that. :smile:

[mnis 11]

A small improvement has given it, but it's still a tangible difference to the other three belts. Well, maybe it is a long time without problems. Should I only do something if it gets worse, or should I better do something now?

Markus