VMC Z Axis problem

[cam1]

Hi:

Control: Fagor 8055 3X CNC (less than 1 Yr old)
Drives: Yaskawa
Problem: Power up machine, release E-stop, control faults out on Z axis. (Z axis drive error CNC code).

Diagnosis: If I turn the MPG slightly (set to Z) while coming off E-stop, the drive does not fault.
The technician came in and did some troubleshooting, by back substitution. He swapped out the Z axis drive card, and that made no diff. He then changed swapped the Z axis Servo, and that also made no diff.

Clue:Upon closer inspection, whenever the machine is E-stopped, and then comes out of E-stop, the Z axis servo tends to surge a bit, causing slight movement of the Z. Feels like the drive "winds up" when it's on E-Stop (the mechanical brake is energized).When it comes off the E-Stop the brake is released, and it moves the axis eneough to cause an error.

The machine has not crashed, and no machine parameters have been changed.It's always sounded a bit noisy when the drives are stationary.

Any insights?

thanks

[cam1]

Update: Fagor Automation Toronto comes through again!
Investigate following error on all 3 axis
Solution: Parameter#29 Servoff=0001 (Servo offset)
make #29=0100
Run each axis in jog mode (10%) and verify following error </= .0001"

The cause for the shift is unknown, but likely reason is electrical noise. Had the Electrician verify that all ground connections are OK. I'm still concerned that something shifted, but the shift effected all 3 axis equally, which indicates a systemic shift. many thanks to Mohit at Fagor Automation Canada.
If you have a Fagor, and need expert advise ask for Mohit.

[philserveng]

if the brake comes off before the motor has got hold of the weight of the axis, there will be movement sensed by the drive. This will cause a drive fault, disconnect the brake and try again to power on, Does the alarm still occur? if not, try adjusting brake off delay timer, make it a second or so longer. If yes, maybe the brake is slipping during the power off period, change the motor brake. Don't try to move the axis with the brake on (disconnected.)

[cam1]

Thanks for the advice.
Just one other question, all other things being equal, if the drive was exchanged for a known good one, along with the drive board, and no change in response was observed, does the problem not lie elsewhere? All 3 axis exhibited the same following error shift
I'll talk to Fagor and mention your proposal.
I'll keep you posted on the results.

regards

[Kiwi]

try adjusting brake off delay timer, make it a second or so longer.

Is this timer value within one of the parameters or in the PLC program.
I have a similar problem when I start my machine centre (Fagor 8055M).
The Z assemble drops and I get a fault.
To over come this, I take some of the spindle weight with my hand during the startup.
I'm thinking the Z assembly needs to be held a little longer and should get this sorted.
Thanks for any advise.

[One of Many]

Update: Fagor Automation Toronto comes through again!
Investigate following error on all 3 axis
Solution: Parameter#29 Servoff=0001 (Servo offset)
make #29=0100
Run each axis in jog mode (10%) and verify following error </= .0001"

The cause for the shift is unknown, but likely reason is electrical noise. Had the Electrician verify that all ground connections are OK. I'm still concerned that something shifted, but the shift effected all 3 axis equally, which indicates a systemic shift. many thanks to Mohit at Fagor Automation Canada.
If you have a Fagor, and need expert advise ask for Mohit.

Most industrial brakes are spring set with no power supplied. When the power is released, in any relay, the one controlling the brake release or the brake itself could be producing an inductive kick back spike, often snubbed with filters or diodes. Normally the brake is isolated from ground via the relay contacts, but if there were bad shielding, anything could be plausible there. If the motion is seen on the position readout during power up, I'd relate this as there is drift happening and a correction when the drives are brought back on line. Is the Z axis counter balanced?

If there is noise on either the ground or servo amp inputs at non-Estop idle. That should be noticable with an O-scope, I'd tend to guess. It may also be a case where the amp gains are set too high to compensate for another problem. The decay in power may produce unexpected motion. You don't mention if the Yaskawa drives are AC or DC, digital or analog. Absolute or Incremental encoders?

Just a few thoughts off the cuff. Take these as generic suspicions that may address the symptom, since my experience is not directly Fagor related.

DC

[DareBee]

Hi CAM

Ya, Mohit is great.
I have had a Fagor controlled knee mill on my next to purchase list for over a year now. Business has just been to tight to go ahead with the purchase considering the machining side of my business has been light for orders.

I want a Fagor controlled mill because I am extremely happy with the versatility and ease of use of my Fagor controlled lathe.
How do you feel about the mill?
Would it live up to my expectations?
Is there anything you would do different?

The Acurite or Anilam controls are more common.
Did you buy from Powermaster or retrofit your own machine?

[cam1]

Hi:
The machine is a Microcut Challenger MM430 from Legere Industrial, purchased brand new last fall with tooling package and 8055iA control for <$50k.
We have an 8055 equipped lathe, and I love the control, it's what prompted me to spec the mill with an 8055 control. I can get a conventional machinist up and running on this machine in a couple of hours. (no crashes in 4 yrs )

Likes: Love the 8055 control, easy to use very intuative , easy to learn and a breeze to run. Nice canned cycles for drilling, tapping and doing little jobs when you are feeling too lazy to fire up the PC. USB file transfer works well, and the 4GB memory ($400) is sufficent for most jobs.
The support is the best I have ever experienced.Fagor knows their product, and actually implement customer feedback. It's really easy to tweak the control with custom menus etc.

Dislikes: Fagor is still the new kid on the block. We're running Solidworks/SolidCam, and getting a post was a hassle (not Fagors fault). The VMC is really nice, and everything works (well most of the time).
If you were to purchase the 8055M, I'd be happy to sive you a Post for Mastercam and SolidCam.

regards