https://youtu.be/xlOz-1yFVMs
:( :( :(
Z motor untighten ?
as told in at other place, most likely a loose Z-Couple. Just try to fix the set screws.
Broken.
Looks like it has been broken for some time with the 2 wear spots. And your prints been coming out ok?
I noticed it sounding odd during the last print, which ran all night, but it finished and came out OK. When I went to run the printer the next morning the coupler was broken and the Z axis didn't work. Anyway, it's back in action now :)
Mechanically speaking, that is a common problem when the motor and shaft do not have a close alignment and they use a weak metal flexible coupling because they are afraid of backlash with a rubber centered coupling.
A “U-joint” with bearing slide axis would last a little longer, or if you can float the motor as they try to do by leaving the mounting screw loose but then you can still have a Z axis back lash issue.
A little more time spent on the engineering of the motor mounting scheme would have better MTBF (mean time between failure).
But what do I know about any of this stuff?
Nothing.
Thanks, Drew. I notice the replacement couplers are the rubber-centered type; the metal one was from my v1 machine s/n 52, which has been run heavily for over 2-1/2 years, so I'm not too upset by the life.