I have a Fanuc Om controller on a Excel/Kiwa VMC. I think it is a 1991. Lately we have been having a few issues on the Y axis. There is quite a step on approach and depart. We had a part that required a finish and it seemed like it was in a different position every time it came out of an arc an into a flat. I could give mote detail on that but for now i will keep it simple and get to the problem.

Came in this morning and went to zero machine. We ended up getting a 406 and a 420 alarm. (i am hoping that those are right as i never thought to write them down). So we reset the machine and tried again. From this point onward all i get is an over travel alarm when i try to zero return.

I checked to limit switches and there doesnt seem to be anything loose or caught in them. I thought about messing with them but i figured since nothing seemed to be wrong it made no sense to create more problems till i was sure it was an issue.

Personally i think there is something more wrong here than a limit switch. There have been to many other issues with that axis in the past. I am pretty sure we actually replaced the drive on it a few years ago.


Hopefully there is someone who has an idea about this as i am at a loss...