Need Help!- Problem with threading cycles

[JerryF]

We have an old Mori ZL-250 that we typically use just for simple parts that are turned, drilled, bored, etc. We have to do a small run of a part that is OD threaded and when we try to use any of the threading cycles we get a 490 alarm which is related to the spindle. This happens in G92, G76 and G32. All other G commands work fine. Any ideas about where to look? Thanks in advnace for any help you can provide.

[Perfect Circle]

What type of Control does it have?

http://www.cncalarms.com/

[JerryF]

It's a fanuc 18i. We think it might be the spindle speed sensor causing the problem.

[Perfect Circle]

It may be an easy fix if its the spindle encoder.
Then it may not be.....
Hope Not!
Check all the connections, unplug/plug back in after cleaning.
Make sure the belt is not skipping teeth on the spindle splines or the encoder pulley, etc.....
Also do the rpm's match what you programmed on the screen?

Let me know what yall find out.

http://www.cnczone.com/forums/fanuc/...lem_-_rpm.html