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NH6300 X chatter

CNC_Tech

Plastic
Joined
Apr 17, 2020
Hello everybody,

I've got an NH6300 that is giving me a bit of a hard time. When I have it running a program the X axis makes a horrible high pitch chatter sound. When we first heard it we thought it was spindle bearings but have since ruled this out. Now where this gets rather strange is it will only do it when running a program. I can manually jog the X the same speed as the program and it does not care in the slightest, within the first minute of running the program X begins to squeal. I have checked the ball screws for damage and they appear to be just fine. The noise happens when it is generally near the home position it does not matter the direction of travel. I am thinking it could be a relay or contactor but I have not yet located any that are bad, I will be going through a wiring diagram here shortly. If you guys could give me some advice on this one I would greatly appreciate it.
 
Post a video with good sound quality showing the conditions where the noise is made. Try to move the microphone (carefully!) into different areas so we can here variations in noise intensity.
 
Milland,

Thank you for the reply, I am now running into another problem. I was off for a day while I was gone somebody (Who doesn't want to talk about it) took one of the servo motors loose from the ball screw, they then for reasons beyond me attempted to home the machine which obviously threw a lot of things out of wack. I've not had any experience trying to get dual servos back in sync with each other but I suspect at this point that is the next move. I talked to DMG their answer was we want to send a tech out which to be honest right now stretches our budget pretty hard. Does anybody here have a procedure to get these two back in sync? Currently I am getting a 410 Servo Alarm : Axis Excess ERR [V]
 
Milland,

Thank you for the reply, I am now running into another problem. I was off for a day while I was gone somebody (Who doesn't want to talk about it) took one of the servo motors loose from the ball screw, they then for reasons beyond me attempted to home the machine which obviously threw a lot of things out of wack. I've not had any experience trying to get dual servos back in sync with each other but I suspect at this point that is the next move. I talked to DMG their answer was we want to send a tech out which to be honest right now stretches our budget pretty hard. Does anybody here have a procedure to get these two back in sync? Currently I am getting a 410 Servo Alarm : Axis Excess ERR [V]

I have worked with the local DMG techs to do it on NZX2000s, but I haven't done it completely myself. I am also using the Fanuc Celos, not the older style on the NHs.

There is a button you will have to switch under settings, operation panel, zero point adjustment. This allows you to move each axis individually, but there are no safeties as far as I know. Be very careful while adjusting stuff in this state. From there you will need to find the parameters for each servos offset from it's reference position. Under NC parameters it should have a label. You will notice the X1 and X2 axis will have different values. On our machines these are in encoder counts and you will have to use the NC parameter that shows the encoder counts to figure out where it is now and how far you need to move. We have done this based on the loading of the axis. So shift the misaligned screw until the loading is similar on the two axis, then reference the encoder counts to figure out how far to adjust your shift by. The move will get you close, but it's take a couple tries and back and forth movements to get it tuned nicely.

Hopefully this is helpful. It's definitely not perfect, but might get you going in the right direction when combined with your manuals. If you need to have them come resync it, I would expect about 4-6 hours. The techs I've dealt with locally have been good and answered all my questions.
 
First of all thank you all for your help, I have the two ballscrews running close enough I can move them now. I am running into my next problem, when I home the machine Y and Z home without issue but once again X needs to be the problem. I home X and get a 500 overtravel alarm. If I power the machine off and back on it comes up with a 410 servo alarm that cannot be cleared, however if I go into the operational panel and turn the machine lock on I can power cycle the machine it comes up just fine and after turning machine lock back off I can move the X axis. Again if I home it I get overtravel but that can be cleared with the reset and it will continue except without it finding home position.
 
First of all thank you all for your help, I have the two ballscrews running close enough I can move them now. I am running into my next problem, when I home the machine Y and Z home without issue but once again X needs to be the problem. I home X and get a 500 overtravel alarm. If I power the machine off and back on it comes up with a 410 servo alarm that cannot be cleared, however if I go into the operational panel and turn the machine lock on I can power cycle the machine it comes up just fine and after turning machine lock back off I can move the X axis. Again if I home it I get overtravel but that can be cleared with the reset and it will continue except without it finding home position.

Just an assumption, the home position for each servo might be based on the encoder counts as well. Now that you shifted the one servo, it might be going outside of the old soft limits before hitting the reference position on the last rotation. Might try looking for a parameter related to the home position under those axis and see how it is defined.
 
Well I'm getting closer thanks to your help everybody thank you, as normal DMG doesn't want to give any information they want to send a tech out so they can get their money. At this point I can move all axis Y, Z, and B will home without issue. I did a zero return on X to get it realigned where it should be but even after a zero return I still get an overtravel alarm when I try to home it, I am thinking it is basing this off the encoders on the servo motors but I am not sure how I can straighten that problem out anybody have any thoughts on how I can get this part straightened out?
 
Whew that was a long one, finally got everything where it should be, a day and a half of getting more familiar with the ins and the outs of the software and I finally got the zero set point where it should be and I have a happy machine. Thanks again to everybody for offering your help I greatly appreciate it.
 








 
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