UM3 - is that belt too loose?

[rhoogenboom 3]

Hi,

I just received my new UM3 this week and I noticed when the print head moved left to right, one of the rear belts is a bit loose. Very loose compared to all the other belts on the machine.

This is the belt to the back of the machine, not the one in the front.

You can even see when the print head is on the right, that there is an imprint/form in the belt of the right wheel (exactly there where the wheel is when the head is in rest in the left rear corner)

Can some comment with an UM3 if their belt is equally loose at that location.

Please see pics for details.

[fbrc8-erin 272]

It is hanging a little loose, it's an easy fix.

If something snags your belt (like possibly the printhead shaft if you're reseating the printhead), it will pull the belt over by a tooth or two on the pulley, creating slackness in one half and tightness in the other (though the tightness isn't really visible.

Loosen one of the pulley set screws on the pulley that belt is attached to it, and it should spring back into place, then go ahead and tighten it back up. There's a short video here:

[neotko 1,417]

Nice visual explanation @fbrc8-erin

Just wondering. Isn't there a slight risk of loosing x/y square?

[fbrc8-erin 272]

Nice visual explanation  @fbrc8-erin  

Just wondering. Isn't there a slight risk of loosing x/y square?

 

Shouldn't lose the XY squaring I don't think as long as you're not moving the printhead while the screw is loose; all the other pulleys are tight and stationary.

The belt should be snapping back to it's original position on the pulley, but it may be worth moving the printhead to the side after it's tight again and checking that the distance between front and rear sliding block and the respective pulleys is equidistant before beginning printing.

[rhoogenboom 3]

Yikes

I'm not entirely sure if I'm comfortable loosening screws on a 5 days old machine. Way too many things I could screw up. I got a exchange in 14 days policy on the machine, I rather think they techie in the shop can sort that out and just get me one which is sorted.

After 3 years doing that, I'm fine (or if it had only costed like 1% of the current price) :-)

Thanks!