UM2 Back Axle Remains Flush?

[sg7019 0]

A quick question, does the back axle of your UM2 remain flush with the housing or move to one side? I have a new machine and it started off flush but is now protruding. The front axle remains flush. looking at the online assembly guide it seems there is no spacer on the left hand side so some movement is likely. Is it expected to move and find a natural 'home' position or is there something wrong? The machine appears to be printing OK (apart from under extrusion but that is under investigation) but I have some concerns about the assembly of this printer and I'm wondering if this is normal.

cheers,

Steve

[ultiarjan 1,215]

This is not ok. It needs to be flush. You probably have a loose pully in that corner. Push the rod back and tighten the pull in place.

[IRobertI 497]

Unfortunately this has been a bit of an issue lately, I've seen quite a few machines with this problem. The fix is easy enough though, push the rod back into place, make sure the belt pulleys are pushed as far as they can go towards the wall of the machine (you might have to loosen the set screw further to be able to move it) and then re-tighten the screw, hard.

Make sure you check all of the pulleys while you're at it.

[sg7019 0]

Thanks for the info, it didn't seem right.

I've looked at the assembly guide on github and as there is no spacer on the side of the double pulley I guess it does have to be pushed to the side, but there is no info on how close it should be to the bearing. I've built a Printrbot and maintained a couple of others but there is info available for those and the github manual for the UM2 is not very detailed, I don't want to damage such an investment or worse have it perform under par. Right now I'm very new to this machine, I don't even know how to get the head out of the home position so I can get access to that corner.

I've had a feeder build issue, a cracked printhead on delivery, this axle problem and in the background a significant under-extrusion issue (stepper skipping on all but the simplest of prints). I've seen great quality out of some prints I've made, surpassing my other machines, but I wonder what is next. I know better than to expect trouble free operation but I did hope that for the price the machine could at least be assembled well.