VF 3 Zaxis Drive fault & table bow

[msteckhan]

Hi Guys,
I have a 96 VF3 (brushless) and ounce in a while I will get a Z axis drive fault alarm while the machine is at idel. Any one have any ideas why I would get this alarm ? It only happens 1 or 2 times a day.....Never during a program, always at idel.....

Also,

The table has a .003 bow in it.
While running an indicator across it is +.003 in the center, exactly all over, any whare on the Y,,,Y is perfect.

The machine is perfectally leveled.(better than .0005 per foot)

Also that shows up in a facemilled plate.
It is .003 thicker at the end of the travel vs the center......

What do you think?
Thanks,
Mark

[HuFlungDung]

I used to get a Z axis drive fault, unless I was using the 4th axis, in which case the fault would switch to the A axis. I guess the 4th axis drive is first in the daisy chain from a small power supply that hooks up to the axis drives, then Z and so on. Eventually that power supply quit working completely, that's when I solved it

Found an exact match from Newark, mucho cheaper than from Haas. Why pay more for the same thing?

As for bow in the table, did you also try sweeping with a indicator on a large radius, just to verify that the top is non-planar? If so, I suppose you could carefully machine the top a wee bit. Make sure the spindle is very accurately trammed or you'll end up with a worse mess. Warm the spindle up for a half hour before facing to alleviate the effects of expansion.

[msteckhan]

Thanks,
The spindle tram shows up exactly the same.
Thanks,
Mark

[helix77]

DONT CUT THE TABLE UNLESS YOU ARE QUITE SURE THAT IT IS THE TABLE THAT IS OUT AND NOT THE WAYS OR BEARINGS....IF YOU ALREADY CUT A PART FIXED ON THE TABLE THE FRESH CUT SHOULD REFLECT THE PARALLELISM BETWEEN THE CUTTER AND THE X AXIS... BUT IF THE FRESH CUT MIRRORS THE TABLE ERROR THEN THE TABLE ITSELF IS 'ROCKING'... BE VERY CARFUL!!

[msteckhan]

ttt
Any more drive fault ideas??????