MB18 Centurion 6 homing error

We have an MB18 with Centurion 6. When starting the mill up and homing, this morning, the Z-axis homed normally, but X seemed to accelerate toward home rather than behaving normally and slowing down as it reached the limits. Has anyone had this happen? If so, what was the issue?

Looking at the diagnostics screens, X and Z report home switch as 1 (on or off, I don't know which) at the last e-stop, and Y reports home switch as 0. That said, I've never looked at the diagnostics screens before this, so I don't know what's "normal."

Here's a short video clip showing what happened when we manually moved the bed away from home, then re-homed.

https://youtu.be/oauqw1SLGb4

After I posted this, I saw a "Similar Threads" list. The first of the similar threads I looked at was this one: https://www.cnczone.com/forums/showt...ing%20problem)

I am attaching the photos I took of the axis diagnostic pages just after the process in the video above. After about 15 minutes, I went down to take better photos, and the X axis was reporting a 0 on the home switch and 0 on the rotary clamp.

I looked at the setup parameters, and the velocity toward home is 150. We have an MB11, as well, which is running as it ought to, and the velocity toward home on that one is 100.

Finally got a hold of a Milltronics service guy. He said it sounds like the home switch is bad, and the velocity toward home is high. He told me I can manually change the velocity toward home, and that might help with homing issues until I can get the switches replaced.

It looks like the X-axis encoder is shot. When manually moving the bed, the X-axis output doesn't budge. Also, after the e-stop is released and reset, the X-axis handwheel turns counter-clockwise all by its lonesome, but the X position read-out does not change.

Ok, my partner took the X-axis motor off and found that the encoder disk had come unglued from the shaft collar. He reattached it with contact cement. The readout now shows movement for the X axis. However, when e-stop is released and drives are reset, the X-axis travels on its own, then faults with a drive error. Milltronics says the balance potentiometer may need adjusting. We'll try that, next.

We tested the home switch, and it appears to be ok.

Buy an encoder from Milltronics the glued disk will not last especially if not centered. if you cant get the following error adjustment with the balance adjustment, you encoder OR wiring to encoder is bad, My suggestion is contact Sporty Bob he will supply replacements at reasonable cost and excellent after sales tech support.

Been there done that.

Ron

Thanks, Ron. I'll check with him.

I e-mailed Bob, who called me that same day and was incredibly helpful with troubleshooting. We determined that the motor is probably what has issues. Bob suggested we try to find someone to clean and service the motor, but also said he had a new motor/encoder/cable assembly.

Long story short, we checked into getting the motor cleaned and new brushes put in, and we decided it was more cost- and time-effective to buy a new motor/encoder/cable assembly from Bob.

Thanks rl49 and sportybob!