X-Belt Mount loose on carriage
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Description

While processing red-tagged Mini 2 today for failing the dimensional accuracy test, I had 2 machines failing in X where the belt was under tensioned. While re-tensioning the belt I found that once the post was removed, the X-belt mount was loose on the carriage.
It seems held in place whenever the post is installed. This is caused by the fastener hitting plastic behind the inserts and makes torque specs ineffective.
It was also reported on T2487 but we currently don't have a solid process that doesn't have a chance of this occurring.

logan created this task.Aug 14 2018, 2:30 PM
logan created this object with edit policy "LulzBot Hardware Products (Project)".
tutley added a subscriber: tutley.Aug 14 2018, 2:35 PM

@logan that is interesting. That sounds like the post was installed before the belt mount was mounted to the x carriage. In any case, this will become irrelevent with the new tensioner system. I think with proper assembly order of operations (ie. install the mount to the carriage before putting the post screw in) this can be alleviated until the ECO is complete

@logan i am not sure i understand the original post. can you clarify? Is the post screw preventing the belt mount screws from being tightened properly? or are you saying the bloom behind the inserts is preventing the belt mount screws from being properly tightened?

logan added a comment.Aug 15 2018, 7:36 AM

@tutley It would be the latter, additionally, T2487 explains that in addition to the plastic being pushed back from normal insert installation, the iron is creating a pool of melted plastic behind the insert so as the last few mm of insert installation is completed, plastic is flowing back into the insert. Due to space constraints I'm not sure if we can make more room behind inserts without making that part very weak. This will be better with the new tensioner system because one of the fasteners is now a through hole, but if the other insert hole isn't any deeper we might run into this still. We see the same with the M-3 inserts on the Y-axis bearing holders.

For the record, I don't understand what you were saying in your first comment. Likely due to the confusion clarified above, granted, but How could the post/fastener be installed if the mount isn't on the carriage? The insert for the post is on the carriage.... Plus it'd make belt install impossible.

DaniAO added a subscriber: DaniAO.Wed, Nov 21, 10:36 AM

@logan are we seeing this as a problem still? There hasn't been any updates since August.

@DaniAO This would be resolved if T3450 gets implemented. Other than that I think we've done all we can with coaching production to prevent this.