[mealborn]

Hi all,
I have been having some trouble with my 1997 Haas VF-10 mill recently. Intermittently, but now more frequently, the Z-axis is making a high pitched whining noise whether moving or holding in position and eventually throws an Error 163 fault for a drive fault, the error claims it is an overload.

I initially thought it was because the counterbalance pressures were low because the Z-axis would sag on power-off (around 1000 PSI, last filled 4 years ago) so I had them recharged to 1175 PSI each and had the hydraulic fluid drained and refilled to 2 quarts in each nitrogen tank. The error still persists, although the Z-axis no longer has the power-off or estop sag issue..

I have posted a video below on Google drive showing the problem. Anyone have any ideas of what to look for or where to start? I've already tried re-seating the connectors for the Z-axis encoder and the low/high voltage connections on the Z-axis servo amplifier. No fault light comes on the servo amplifiers when the error occurs. I've looked at the service manual, but it only mentions amplifier shorts, servo shorts, or cable shorts which I don't believe to be the issue because then it wouldn't be an intermittent issue nor would I be able to clear the error if that was the case.

Is this a mechanical issue or is there some parameters for the Z drive that I could change (filtering, PID gains, etc)?

Video of me demonstrating the noise that leads up to the error tripping: https://drive.google.com/file/d/1j6U...ew?usp=sharing

Image of the error screen after it trips: https://drive.google.com/file/d/1kOx...ew?usp=sharing
Image of the machine serial number: https://drive.google.com/file/d/1kEu...ew?usp=sharing
Image showing no fault leds on the servo amplifiers after the error trips: https://drive.google.com/file/d/1kS1...ew?usp=sharing

Thanks for your assistance,
Matt

[BigNizzy]

I would swap the Z-axis servo amp with another axis, they are prone to failure ( we have machines of a similar vintage and keep one spare from back before they were service exchange!) and see if the problem follows the amplifier or stays with the motor.

[cncmakers001]

Should be mechanical issue, if it is the driver problem, then it will alarm all the time.

[Trackiron]

Yes, try adjusting your gain values for the axis giving the issue. My new at the time TM2P would start bussing on the Z axis slowly if it sat for a while turned on. I have tuned that type of noise down by this method. If i remember right I first took a picture of the values, hit e-stop, turned parameter lock off, and then changed it by increments of 1000. Tried the machine to see if the problem got better or worse.

I am not sure what the root cause of it is though. Could be several things in my mind. I won't guess here however as I don't want to BIAS anyone wit bad information.

[fire8pyro]

likely an amplifier if the motor or cables aren't shorted out. Haas has a diy site for troubleshooting you can use diy.haascnc.com. i would look up servo amplifier troubleshooting.
you might need an auxiliary axis load if your machine doesn't have any more "dummy" amps left this could also cause the issue.
i would also inspect the ballscrew as previously mentioned it could be a mechanical issue.

[Donkey Hotey]

Yeah, you've probably fixed this by now but, that's a bad amplifier. My TL-1 did that on the X axis with no load. The motor would make a squeaking noise, once per revolution of the handwheel, in the same zone, even though nothing was wrong with it. Same thing: the motor was oscillating back and forth and causing the noise. New amp fixed it.