Integrex C-Axis bouncing issue

We've got an issue on an Integrex i400 with Matrix2 control where the 'C' axis is bouncing.
When doing a milling process and the 'C' axis is supposed to be stationary, it is actually rocking about 1 degree back in forth. Like it is seeking.

After my first call to Mazak I was sent an email with 2 parameters listed (SP038 and SV038) and was told to try and adjust them. After calling back to see how to adjust them, I talked to a different serviceman and was told to put a magnet on green wire on the servo drive to try and help reduce the noise.

I've adjusted both of the above parameters up about 200 and it didn't help any, haven't tried the magnet, but was hoping to see if anyone else has had a similar issue and could provide some thoughts. Thanks

Is it moving under cutting load or just when it's sitting there before the tool touches? If it's under load you could try C-axis Clamp M210 or C-axis brake M211 to see if that helps at all.

CNC Hacker said:

Is it moving under cutting load or just when it's sitting there before the tool touches? If it's under load you could try C-axis Clamp M210 or C-axis brake M211 to see if that helps at all.

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Thanks for the reply, but the C-axis bounces during a C-Axis rotation during a machining/cutting process (i.e. the tool is in the part and the C-axis is rotating while cutting). The bouncing occurs after a C-axis stops rotating.

If we use the point machining process and the C-axis is stationary (i.e. indexes to a position and then cuts at a point) then this problem does not exist.

My okuma uses a brake caliper to drag on the disk brake. Their manual says to grease the disk to prevent this stick-slip issue.
Does the Mazak have a disk brake?

if its belted i would first try to tighten the belt

It's direct drive, no belts. I do not believe it is a mechanical issue, but an electronic one. We can hear a very high pitched noise coming from the spindle.
I gave up on Mazak supporting their product and now working with Mitsubishi. Night and day difference between Mazak and Mitsubishi's idea of service is.

Sounds like Mazak wanted you to adjust the gain settings for the drive. Those settings should never really change. I would suspect your encoder or drive.

Do you happen to remember how to adjust these parameters?

Integrex C axis, C axis is operated by encoder. C axis control counts pulses , that C axis encoder ERM280 sends to MDS-DH servo. If C axis is jumping around, that is either encoder is faulty, or MDS unit.

You can swap MDS unit spindle unit with another machine and test it.
Encoder is more complicated, you need special PCB board to put in between and check signals with oscilloscope.

Mazak makes machines, Mitsubishi makes controls and MDS units. Mazak, even in Japan, heavy - difficult electrical issues, refers to Mitsubishi for qualified support.
....
some Matrix controls have PLG diagnosis functions, it is DIAG menu, servo and spindle. On SPINDLE diagnostic page, there will be ENCODER DIAGNOSTIC, SUB ENCODER DIAGNOSTIC.

that can tell you errors, in case MDS-DH is able to detect them.