[acncguy]

Hello -

We have a Horizontal Boring Mill with a Mitsubishi Meldas 500 series controller and out of nowhere we are getting a "Z Axis OT (overtravel)" alarm which has shut the machine down because it is stuck in feed hold and the only thing we can do is manually handle the machine in all axes. The machine will not go into auto mode. We cannot clear the alarm by turning the control off. We cannot go into MDI mode. It is just stuck with this alarm. Apparently there are no physical limit switches on the machine, they are set in the software (I don't know anything about this ... I was told this by our maintenance guy).

This is what was happening right before this alarm occurred: The machine had just tool changed and the magazine was rotating to get the next tool, the machine was positioning in the X-axis and Y-axis and the operator had just changed the wear offset by -.004 for the tool that was in the spindle (while the machine was moving, but before it was commanded to move in Z). The machine stopped a few seconds after entering the wear offset, but this is something the operator has done many times before, with no issue. The G43Z line wasn't for three more lines (the machine positions in X & Y, then takes the slop out of the B-axis by incrementally moving one degree CCW, then CW to position, then the B-axis clamps, then the G43Z line).

The machine is configured so the Z-axis is the column of the machine and the quill is the W-axis, if that matters...

Of course, we have a very hot job we are trying to get finished by the end of the month, so it's perfect timing. We are stuck and don't know what to do and is it true that Mitsubishi is out of business? Heard that from the maintenance guy as well. So, we don't know who to contact to help us with this, so if anyone has any suggestions on that as well, it would be appreciated.

Thanks for any help.

[ifixcnc]

Mits is WAY to big to fail. Mitsubishi Electric Automation Inc. - MEAU Home

[ifixcnc]

It sounds like you have had a wire or limit switch problem.

[acncguy]

Thanks for the info.

The maintenance person says there is no limit switch (I don't know enough about it to say whether this is possible or not). The machine can be handled with the micro-pulse generator in every axis, including Z, however the machine does not come out of feed hold and will not go into auto mode, or any other mode, including MDI.

We are stuck and don't know what to do at this point. I emailed Mitsubishi Electric (the website ifixcnc provided) to see if they can help....

[ifixcnc]

A call to the machine builder may be your best answer. Mits phone Techs are pretty good as well. The phone number is on the page I linked for you. They are on Chicago time.