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x belt over tightened
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Description

Upon further investigation into the high x backlash printer @franklin brought over, I noticed the x belt parts had been cracked from over tightening. Not sure how many machines might be like this as it is not obviously broken when fully assembled.

I was looking over the x belt and saw the clamp on the right was cracked at the insert.
I then removed the interface board and saw that the part was split along the layer lines from being over tightened.

The belt tension is at 39.1 with the cracked parts meaning that the belt was tightened way above the 23-45N range prior to cracking

Event Timeline

tutley created this task.Mon, Jun 3, 10:38 AM
logan added a comment.Mon, Jun 3, 11:03 AM

I have seen the X Belt Clamp (photo right) cracked like that before, was certainly over-torqued. Currently it is spec'd to 5in*lbs at step 5 here: https://ohai.lulzbot.com/project/final-assembly/quiver/
I doubt the part cracks under that torque, but would require a little test to be sure.

The breakage at photo left is quite impressive though.

logan added a comment.Mon, Jun 3, 11:04 AM

It may have been over-tightened in trying to combat the backlash. Ideally though I think one should seek to eliminate excess drag first.

@logan yea i kind of doubt the part would crack at 5 in*lbs as well.

DaniAO added a subscriber: DaniAO.Thu, Jun 13, 11:57 AM

@logan we have only seen this on one machine or more?

For breakage I am only aware of this occurrence

Its hard to say how many there have been. could be just the one, could be a lot. The problem is you cannot see the broken part without taking the interconnect board and mount off.

DaniAO closed this task as Resolved.Fri, Jun 14, 3:08 PM
DaniAO claimed this task.

Okay, since we have only seen one for now going to close this one down. But it can always be reopened.