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Deckel FP4NC Z-Axis jumping / vibrating while moving

Tom Double

Plastic
Joined
Feb 27, 2024
Location
Germany, Ulm
Hi,
we have some trouble with our Deckel FP4NC with Dialog 11 control.
While moving the Z-axis in positive or negative direction the axis moves smooth for a few millimeters and than starts vibrating and makes a rumbling noise for a few seconds. After that the axis moves smooth again for a few millimeters and than starts vibrating again with that rumbling noise. From time to time the control shuts down with error "7103: Lageregelfehler Z-Achse".
The behaviour seems to be similar to the error described here in 2010 for the X/Y axis https://www.practicalmachinist.com/...fp4nc-x-y-axis-vibrating-while-moving.198637/.
In our case X/Y axis move smooth without problems.
We performed the following steps without success, the problem still remains :
- checked z-axis clutch, cluch is ok and does not slip
- checked z-axis Bosch servo control by exchanging Z-axis control with Y-axis control, Y-axis moves smooth with the Z-axis servo control
- replaced NRP board
- replaced NZP board

Does anyone have an idea where to look further ? Is somebody familiar with the change of the NRP board ? Are there any settings (DIP-Switches) to make when replacing the board ? Could the z-axis servo itself be part of the problem ? Does anyone have an idea of the timing for the signals provided by the rotary encoder of the z-axis servo ? I checked the signals of all 3 channels with a scope. All channels provide rectangle CMOS signals when the servo is rotating. Any idea what signal the speed generator should provide when the servo rotates ?

Any idea or suggestion would be highly appreciated.
Thank you very much.

Cheers Tom
 
Hi,
we have some trouble with our Deckel FP4NC with Dialog 11 control.
While moving the Z-axis in positive or negative direction the axis moves smooth for a few millimeters and than starts vibrating and makes a rumbling noise for a few seconds. After that the axis moves smooth again for a few millimeters and than starts vibrating again with that rumbling noise. From time to time the control shuts down with error "7103: Lageregelfehler Z-Achse".
The behaviour seems to be similar to the error described here in 2010 for the X/Y axis https://www.practicalmachinist.com/...fp4nc-x-y-axis-vibrating-while-moving.198637/.
In our case X/Y axis move smooth without problems.
We performed the following steps without success, the problem still remains :
- checked z-axis clutch, cluch is ok and does not slip
- checked z-axis Bosch servo control by exchanging Z-axis control with Y-axis control, Y-axis moves smooth with the Z-axis servo control
- replaced NRP board
- replaced NZP board

Does anyone have an idea where to look further ? Is somebody familiar with the change of the NRP board ? Are there any settings (DIP-Switches) to make when replacing the board ? Could the z-axis servo itself be part of the problem ? Does anyone have an idea of the timing for the signals provided by the rotary encoder of the z-axis servo ? I checked the signals of all 3 channels with a scope. All channels provide rectangle CMOS signals when the servo is rotating. Any idea what signal the speed generator should provide when the servo rotates ?

Any idea or suggestion would be highly appreciated.
Thank you very much.

Cheers Tom
Whenever I have had problems of this kind in the past, it has been recommended to clean the brushes and commutator of the tach generator. If you remove it do not remove the rotor from the stator.
I do not remove the unit. I run it with the motor and apply 600 or 1000 grit paper and brake parts cleaner. This is now the first thing I try, and it has worked every time.

Chris
 
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May be irrelevant but we had similar issues on a Bridgeport where the lube oil got into the encoder.
 
Hi Chris, hi Stainless
thank you for your responses.

Chris:
The servo is a "modern" type without brushes and commutator. The decoder uses Opto couplers for the rotary decoder . The device (s) for the tacho gen i could not identifiy so far because the label on the device is not readable anymore.

Stainless:
The decoder board is clean. No lube oil or other dirt is visible.

Tom
 
Your error description is:

71 03: Lageregeltoleranz ueberschritten
Erk: Im lagegeregelten Stillstand hat der Abstand zwischen Soll- und Istposition den zulaessigen Wert ueberschritten
(Maschinenparameter -Lageregeltoleranz")
Wir: Not-Aus.
Bes: Steuerung wieder einschalten. Gegebenenfalls Verdrueckung der
Maschine beseitigen oder Toleranz erhoehen


The servo does not have a rotary encoder.
I'd make sure the axis is moving freely and not binding.
Be careful when removing belt from Z servo, as the z axis may come crashing down (if screw is very worn).
It seems unlikely that the screw is bad, but it is very easy to remove the the screw to take a look at it and its bearing.
You are in the wrong sub-forum.
 
Hi Martin,
thanks for your return.
We dismounted the z-axis servo to see if the axis is moving freely and smooth. That's ok - the axis is not binding.
"if screw is very worn" : which screw do you mean ?
With the belt removed (table is supported) we fell some play of the toothed belt wheel of the z-axis spindel. Is that OK or should the belt wheel be without any play ?

In the schematic there are 3 channels noted "Drehgeber". I checked this channels with a scope wihile the servo is turning. Do you know the function of those three signals ?

How can I move the post to the correkt sub-forum ?
 
We dismounted the z-axis servo to see if the axis is moving freely and smooth. That's ok - the axis is not binding.
"if screw is very worn" : which screw do you mean ?
the lead screw
With the belt removed (table is supported) we fell some play of the toothed belt wheel of the z-axis spindel. Is that OK or should the belt wheel be without any play ?
On the z lead screw play is not so critical as the force is only ever downwards.
In the schematic there are 3 channels noted "Drehgeber". I checked this channels with a scope wihile the servo is turning. Do you know the function of those three signals ?

The term "Rotorstellungsgeber" is not a rotary encoder. Look for "Abtastkopf" in the wiring diagram
How can I move the post to the correkt sub-forum ?
I don't know.
 
Thank's again.
Ok I will check the schematic tomorrow again. Is there a manual how to remove the z-axis lead screw ? We have just the technical drawings but could not figure out yet how to remove the z-axis spindel (=lead screw) ? The table is already removed so if "it's very easy" to remove the spindle we could do this tomorrow and check the spindle.
 
Thanks to Chris and Martin we could localize the fault and (almost) eliminate it. The problem was an erroneous signal from the tach generator that made the z-axis jump and vibrate as described by Ross Cummings in the link given at post #14.
We replaced the z-axis servo.
With the new servo the z-axis moves smooth but we get the error message 7104: "Geschwindigkeitsabgleich Z-Achse" (velocity adjustment z-axis).
I think the error message is due to the fact that the new servo provides just 1.8mV/min output of the tach generator whereas the old servo provided 2.8mV/min tach gen output.
Does anybody know the procedure how to adjust the z-axis velocity to get rid of error 7104 ?

Cheers Tom
 








 
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