Near the end of the fall semester I got an email from my lab assistant who reported the Z axis of our old Meteor CNC wasn't working. 

A few day before that I'd noticed the Z axis was slipping, and traced the reason down to a loose coupler between the stepper and the drive screw. Tightened the screw with some Loctite and all seemed well, so I was surprised to get that email. 

 

For reference this Meteor lives in a room with 2 other Probotix CNCs, but has been the workhorse for flat cuts mainly furniture hardwood parts. The Nebula to its right has a 4th axis on it which gets used a few times each semester. The wide gantry allows the bit to vibrate/chatter using a 1/4" end mill in hardwoods so we haven't been using it for hardwood flat work unless the Meteor was busy.   

 

The meteor had also gotten new drive nuts on X,Y, and Z the previous semester.  When turned on the CNC steppers can't normally be turned by hand, but now the Z axis stepper CAN be rotated, so it appears it isn't getting any signal or power from the controller.  No movement on the Z at all running G-code or just jogging it with the keyboard.  LinuxCNC thinks it is moving as it updates the coordinates when jogged, but the Z stepper never moves.  

 

I'm off for the holiday break, and know either the stepper or the controller board for Z is bad. I think I'll swap the X and Z jacks and see if the flaw is still at Z or has moved to X.   Sad to have a machine down, although that Meteor has lived a tough life and been a busy machine. 

 

4D  

Edited December 23, 20205 yr by 4DThinker

Late follow up about the college Meteor....   After swapping the X and Z axis cables the Z axis stepper works and the X axis stepper doesn't.  Looking to see if a stepper driver replacement was available i found this info on the Probotix wiki page:  "DEPRECIATED: This product is no longer made nor maintained.".

So we have ordered a new controller box for it, but will have to re-wire all the steppers on the Meteor as the old controller was monopolar and the new controllers are bipolar.   BTW my personal Meteor was bought just a few months before this college Meteor, and initially had the same monopolar controller.   When mine failed Probotix replaced it for the cost of shipping and Len (owner) told me using monopolar drivers was a decision he greatly regretted.   

 

While the college Meteor was a workhorse CNC that survived 4+ years before eventually failing I suppose a lesson here when looking for a CNC is to make sure it uses bipolar controlled steppers.

4D