I had a look last night and found that the motor driver for the Z axis will need to be replaced. The collet really does look like it had a hard crash, and that may have pushed the driver over the edge. It’s out of service for the moment.
To the operator: please don’t feel too bad about it! CNC machining is accident-prone even when you’re doing everything right and paying attention. I have a permanent palm-shaped mark on my forehead for this reason.
Someone please put an Out of Order sign on it. I forgot to do that before I left.
In the past we have had the Z axis driver go bad, and on digging deeper, I have an idea why. The motor drivers have a settable current limit that you adjust for your particular need. It’s set by adding a resistor between two terminals. When I pulled it apart, I realized there’s no resistor installed at all, so all axes are operating at the maximum current of 7 amps. For the motors we have, that’s probably too much anyway, and running the driver at full current all the time shortened its life.
(Side note: the Z axis driver is more susceptible to damage because the machine spends long periods of time at an unchanging Z position. X and Y move around a lot, and the transistors in those driver get a break; it’s two transistors on and two off, alternating with every little step. For a constant Z position, it’s two on for a long time, stressing them. We had previously lost two of the five motor drivers the machine came to us with. At least one, and maybe both, were used on the Z axis. Now I know why they didn’t last.)
I never noticed there’s no current resistors before because they’re installed on the bottom of a circuit board. Often the bottom of things is not visible from above, and that was the case here. I put in resistors to limit the drivers to 5A.
That made the Z axis run better, although I didn’t test it fully because it was getting late. I’ll check it out more carefully tonight.
It may be usable, but consider it marginal, and don’t waste expensive materials on it. I wouldn’t trust it for anything important.