DC Servo Vibrates on Fanuc 6M

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03-23-2011, 03:34 PM
parametric.ms

DC Servo Vibrates on Fanuc 6M

I have several problem with fanuc 6MB at Yamaguchi MC
1. when I move X axis to (-) direction it goes smooth. but if I move to opposite (+) direction, the servo vibrates so hard.
2. its happen to Z axis too with contrary case. when it goes up (+ direction) looks smooth. but if I move to minus direction, it just move a little then alarm comes up. (430 Z Servo)

I've compared whole parameter with Y axis with normal condition,but no luck. its still the same. Maybe I miss some parameter

What should I check to fix that problem?
Thanks in advance

PS : DC Servo Motor type 5M with VCU A20B-0009-0320
03-24-2011, 01:06 PM
parametric.ms

where is Al The Man and Dan Fritz ? I need you here ASAP

I swap both servo and drive with Y axis but the problem still on X axis
I checked the DIAG 713 bit 4-5 works fine for Pulse coder
03-24-2011, 02:37 PM
3d GEORGE

Servos vibrate.

We had similar problem with our 6M Pratt & Whitney VMC machines. We discovered that if you can, remove the servo end cap. This should expose the servo encoder. Don't confuse with the encoder on the ball screw. Spray servo encoder with electronic cleaning spray available at Radio Shack or Best Buy. Cycle servo manually several times. Worked for us.
03-24-2011, 02:44 PM
greenery_fr

Quote:

Originally Posted by parametric.ms

where is Al The Man and Dan Fritz ? I need you here ASAP

I swap both servo and drive with Y axis but the problem still on X axis
I checked the DIAG 713 bit 4-5 works fine for Pulse coder

First check +15 volt -15 volt and +5 volt on your Master PCB. If it Ok may be you had problem with master PCB. The main problem is in hybrid IC APC06
03-24-2011, 03:29 PM
parametric.ms

Quote:

Originally Posted by greenery_fr

First check +15 volt -15 volt and +5 volt on your Master PCB. If it Ok may be you had problem with master PCB. The main problem is in hybrid IC APC06

Is it Freq to Voltage Converter IC? where is the location on master PCB?
03-24-2011, 03:32 PM
parametric.ms

Quote:

Originally Posted by 3d GEORGE

We had similar problem with our 6M Pratt & Whitney VMC machines. We discovered that if you can, remove the servo end cap. This should expose the servo encoder. Don't confuse with the encoder on the ball screw. Spray servo encoder with electronic cleaning spray available at Radio Shack or Best Buy. Cycle servo manually several times. Worked for us.

Like I describe, seems look no problem with pulse coder. It works at minus direction smoothly. But I'll double check just for make sure
03-24-2011, 04:02 PM
mike-at-thorn

On the older machines with DC motors, I found that in the case of vibration, cleaning the brushes and armature usually solved the problem. The brushes are located at 90 degree increments around the motor housing under rubber caps. Keep track of which hole the brushes came out of. Blow them off with clean dry compressed air and then clean the armature with a pencil eraser. If it's the problem, the eraser will come out black and sooty. Blow thru the brush holes with compressed air, but try not to breath the dust.
03-24-2011, 04:22 PM
ITT-Student

This is an A06b-6047-hxxx servo drive correct? Are both servos identical?
03-24-2011, 04:43 PM
parametric.ms

Quote:

Originally Posted by ITT-Student

This is an A06b-6047-hxxx servo drive correct? Are both servos identical?

3 axis are identical. A20B-0009-0320. I already swap whole unit (drive & motor) X to Y but had no luck still vibrating on X. I haven't swap with Z axis
03-24-2011, 04:48 PM
parametric.ms

Quote:

Originally Posted by mike-at-thorn

On the older machines with DC motors, I found that in the case of vibration, cleaning the brushes and armature usually solved the problem. The brushes are located at 90 degree increments around the motor housing under rubber caps. Keep track of which hole the brushes came out of. Blow them off with clean dry compressed air and then clean the armature with a pencil eraser. If it's the problem, the eraser will come out black and sooty. Blow thru the brush holes with compressed air, but try not to breath the dust.

the 1st thing that I done was disassembled motor from ballscrew. checked the carbon brush, remove and clean armature from dust with clean dry compressed air.but nothing change even I swap the motor
03-24-2011, 05:11 PM
ITT-Student

So the problem didn't move with the drives or motor? If this is the case then maybe you have some "noise" near the axis's or cabling? Do you have manuals on the fanuc 6?
03-24-2011, 05:16 PM
parametric.ms

Quote:

Originally Posted by ITT-Student

So the problem didn't move with the drives or motor? If this is the case then maybe you have some "noise" near the axis's or cabling? Do you have manuals on the fanuc 6?

yes precisely... did you mean noise that affected to command signal? I have the manual doc with scan quality
03-24-2011, 05:17 PM
ITT-Student

Quote:

Originally Posted by parametric.ms

3 axis are identical. A20B-0009-0320. I already swap whole unit (drive & motor) X to Y but had no luck still vibrating on X. I haven't swap with Z axis

You do realize that A20B-0009-0320 is just the top board on the servo amp, just swapping these without the base of the drive could leave the problem where its at if there is a problem with the power transistors or bridge rectifiers leaking AC.
03-24-2011, 06:10 PM
parametric.ms

Quote:

Originally Posted by ITT-Student

You do realize that A20B-0009-0320 is just the top board on the servo amp, just swapping these without the base of the drive could leave the problem where its at if there is a problem with the power transistors or bridge rectifiers leaking AC.

Did I mention whole unit? which mean top board include base of drive.
I'm not really sure there's a problem with DC drive (TM,DM). There is something with voltage command. but how come?
03-24-2011, 06:18 PM
Al_The_Man

So If I have this right, you have swapped the drive and the motor and it stays with the X?
Did you try the motor disconnected from B.S.?
Do you have resolvers on the motor?
Al.
03-24-2011, 06:32 PM
parametric.ms

Quote:

Originally Posted by Al_The_Man

So If I have this right, you have swapped the drive and the motor and it stays with the X?
Did you try the motor disconnected from B.S.?
Do you have resolvers on the motor?
Al.

yes thats right Al, still on X at + direction.
what do you mean with BS? ballscrew? I've tried with no load, just lay on the floor. the motor use Pulse coder 2000 ppr
03-24-2011, 06:33 PM
Al_The_Man

Disconnect for the ball screw?
Al.
03-24-2011, 06:38 PM
parametric.ms

yes of course sir.. I've tried with no load, just lay on the floor. the motor use Pulse coder 2000 ppr
03-25-2011, 03:58 PM
kcho

Hi could you send me your the scanned manual?
I have this problem once check the encoder coupling if you have some backlash between the encoder and the motor, the motor vibrates.

Carlos
08-06-2022, 08:11 AM
Prnya

Quote:

Originally Posted by parametric.ms

yes of course sir.. I've tried with no load, just lay on the floor. the motor use Pulse coder 2000 ppr

Greeting! I have same problem with X axes DC motor. Do you solved problem?