After running perfectly for the past couple months after diagnosing a 401 alarm to a cracked insulator on an indicator fuse my Okuma NC4PS running a Fanuc 6T is having another issue. Over the past couple weeks I'd be able to run 4-5 hours without any problems. After that period of time, if I didn't keep the machine cycling (i.e. kept it running parts vs. sending it home while I was tweaking a new program) a 410 X Axis alarm would sound. If I shut the machine down for an hour or so I could get it to start back up. When the 410 alarm sounded, the X axis servo was quite warm. Enough so, that I couldn't hold my hand on the outer casing more than a couple seconds. I never got an overheat alarm, just the 410. For a week or so just shutting the machine down overnight and it would run another 4-5 hours the next day without any issues.
Figuring the servo was dying I got a remanufactured unit on order from Eastern CNC. However, this week I wasn't able to get the machine to start at all. The minute I turned on the control and then the hydraulics I'd get an immediate 410 alarm. Swapping out the existing servo for the new one does not eliminate the alarm. What is perplexing, though is that after hitting the reset button and so long as I am rotating the jog wheel I can move the X axis. The minute I stop using the jog wheel the machine alarms out with the 410 and I can hear the contactors in the cabinet drop out.
I did check the ball screw for any binding. It's as smooth as can be. However, I do believe the brake that keeps the turret in place when the power is off never did release. This is an electromagnetic unit that pulls in a pressure plate when power is applied. When the power is off the magnet releases and springs apply force to clamp a friction plate in place to keep the ball screw from turning and the turret from falling. I am thinking the X axis servo was constantly operating against a brake that never would release. I am planning on replacing the brake (an Ogura MNB 0.4 90V DC unit is on there now... strangely enough the machine is sending 150 VDC to it according to my meter...) but would like to solve the 410 error. Before I go down the road of replacing the drive board are there any suggestions as to what else may be worth checking??
Figuring the servo was dying I got a remanufactured unit on order from Eastern CNC. However, this week I wasn't able to get the machine to start at all. The minute I turned on the control and then the hydraulics I'd get an immediate 410 alarm. Swapping out the existing servo for the new one does not eliminate the alarm. What is perplexing, though is that after hitting the reset button and so long as I am rotating the jog wheel I can move the X axis. The minute I stop using the jog wheel the machine alarms out with the 410 and I can hear the contactors in the cabinet drop out.
I did check the ball screw for any binding. It's as smooth as can be. However, I do believe the brake that keeps the turret in place when the power is off never did release. This is an electromagnetic unit that pulls in a pressure plate when power is applied. When the power is off the magnet releases and springs apply force to clamp a friction plate in place to keep the ball screw from turning and the turret from falling. I am thinking the X axis servo was constantly operating against a brake that never would release. I am planning on replacing the brake (an Ogura MNB 0.4 90V DC unit is on there now... strangely enough the machine is sending 150 VDC to it according to my meter...) but would like to solve the 410 error. Before I go down the road of replacing the drive board are there any suggestions as to what else may be worth checking??