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Author Topic: Fitted new spindle  (Read 235 times)

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Fitted new spindle
« on: October 06, 2018, 04:12:24 PM »
Hi everyone,
My question is a simple one , I used to zero the Z axis using the probe go to zero feature,  before each zeroing I did a check to make sure that the green digitize light came on when I touched the bit. I have fitted a virtualy identical spindle and now when I do the green digitize test the light does not come on.  I have not changed any of the settings. Has anyone had a similar experience? Or does anyone know why? I  have a Chinese 3040T that I use just for fun. Is it back to the piece of paper or can you help?
Many thanks
Eugene
Re: Fitted new spindle
« Reply #1 on: October 06, 2018, 04:41:27 PM »
Hi,
I suspect that the spindle nose of your new spindle is electrically isolated from the frame or earth of your machine.

The probe circuit is roughly:
1) A current limited voltage on your touch plate (isolated from earth)
2) When the tool touches the plate a current flows from the plate through the tool....through the toolholder....through the motor
   armature...through the bearings....to the case of the spindle to earth, the frame of your machine.
3) Mach detects the current flow as a probe contact.

If that circuit is not complete, lets say you have ceramic bearings in your spindle then the current cannot pass through them and Mach
would not detect the fact that the tool has in fact touched the plate.

May I suggest, as an experiment, run a second wire from the toolholder of your spindle to earth. Then try probing again. Until you can
get Mach to recognize when the tool touches the plate then all bets are off.

Craig
My wife left with my best friend...
     and I miss him!
Re: Fitted new spindle
« Reply #2 on: October 06, 2018, 05:17:48 PM »
Hi,You have described the scenario perfectly. I will do as you  recommend tomorrow.  Many thanks, Eugene
Re: Fitted new spindle
« Reply #3 on: October 07, 2018, 06:24:21 AM »
Hi,

May I suggest, as an experiment, run a second wire from the toolholder of your spindle to earth. Then try probing again. Until you can
get Mach to recognize when the tool touches the plate then all bets are off.

Craig

Now why didn't I think of that, it worked a treat. I think it was a case of me looking for a difficult solution when the simple answer was staring me in the face,

Many thanks