Z-axis jump

[shupej]

I am having a problem with my Fadal 4020 mill machine. When I jog the Z-axis, the machine will intermittently stop responding to the jog command. When this happens, there is usually a short, delay and then the Z-axis will jump in a random direction and in a random amount. This happens when jogging the machine. When a program is running, it will fault out as a Z-axis fault. Does anyone have an idea what could be the problem?

[shupej]

Did I give enough information about the symptoms?

[Delw]

could be your resolver/encoder going bad,
Could also be the couples is loose or snapped between the ball screw and the motor or the couple for the resolver is broke or loose.

I would check the couplers first its a quick check.
the encoder coupler is on the top of the z axis motor you will have to pull the cover to see it

Delw

[Techman]

Another simple thing to check are the sprockets/bearings for the counter weight. I had a bearing go bad and it would cause the counter weight to drop a bit when the Z axis went up or it would catch when the head was going down. Either way it made quite a "thunk" sound.
Hope this helps!
Techman

[shupej]

Thanks for the help; if I was to replace the resolver what steps would, I need to do to bring the machine back on line? Does replacing the resolver effect the calibration of the axis?

[iess525]

I sent you a message. Send me your info and I will try to help you out over the phone.

[Delw]

Originally Posted by shupej Thanks for the help; if I was to replace the resolver what steps would, I need to do to bring the machine back on line? Does replacing the resolver effect the calibration of the axis?

its simple takes about 10-15 mins,

However are you sure its the resolver?
replacing the resolver will move your home position how ever you turn the resolver slightly to get it back inline with the home marks. its extreamly easy.

if you have your resolver out you can spin the shaft if its choppy or has drag its pretty much going bad, if its smooth its good. ( not always the case but 9 times out of 10 it is)



Delw