Not exactly a universal problem, but: I have a wells index 700 series CNC mill that when you put into traverse mode gets stuck frequently. It seems to be a timing belt issue, esp since the belt broke when trying to adjust the motor. This is a short post on replacing the belt since I couldn't find any documentation.
As a bit of background, if the documentation is correct, it weighs more than 3,500lbs. Unfortunately, when it was moved, the servos got whacked and it's been a problem getting it running when controlled by computer (manual is fine).
The Y axis drive was giving a lot of problems for a while, until a real machinist came over, moved the motor around and then it worked. Turns out it had been hit and moved slightly out of alignmnet --- this was making it slightly more difficult to turn the handle, which was causing the torque sensor to stop movement.
I started getting the same problem on the X axis so started fooling around, and making it tighter. 20+ year old belts don't like to be made tighter and this one promptly broke.
I paniced.
I then called the company and the owner hadn't had to deal w/ that before (?!) so wasn't sure what to do. He said he'd get back to me. He then said I could maybe get the table to seperate and go from there. These instructions were fairly vague to someone that don't know much about machines.
In any case, it sucks having a broken machine so sans documentation I started taking bolts off. Turns out it was actually not that hard to replace the belt, despite some initial false starts.
Here's more photos than anyone other than the one wells index owner out there would want to see :)
The handwheel for turning the milling table in the X axis, you can see the motor used by the computer as the cylinder below it: the belt in there running from the motor to the handle (to turn it) is broken:
After removing the handle, we stare at a bunch of bolts and then start removing four that seem like they might help:
Turning the X axis handle, the unit comes seperated from the table! This is great since somehow we need to get these apart to get the continuous belt in there:
We crank some more and it really seperates
Unfortunately the large screw (which controls the table movement) isn't about to come out, neither is the end unit. After staring for a while I realize (duh) that you can slip the belt over the two pulleys from the bottom if you take the servo motor off.
We remove it:
Slip the belt up:
Put the motor back and the belt into both pulleys:
And then reassemble:
I then run a few programs to move the X back and forth and everything works. No torque sensor problems. Nothing breaks. AWESOME.
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