Stop the spindle if contacting metal?

[jong]

Has anyone used the Zzero or Estop hardware to emergency stop the spindle if it contacts metal?

I cut open plastic enclosures using my PRTAlpha Benchtop. I have some enclosures with batteries that could cause a serious problem if they were mistakenly contacted by the cutter.

So we were thinking of guarding the battery area with a piece of sheetmetal so if the cutter contacted the sheetmetal it would automatically stop cutting - similar to the Zzero approach.

Obviously I can't connect the aligator clip to the rotating spindle but maybe a wire brush could rub the side of the rotating spindle which would ground the wire if the cutter contacted the metal guard.

Has anyone seen or tried a similar setup?

Can this approach be spliced into the Estop? Or should I try to somehow copy the code from the Zzero routine into my cutting file?

Cheers

[Brady Watson]

Jon,
If you have good brushes in your router (or any spindle) you do not need the clip.

There are 8 inputs available on the newer tools, 4 on the older tools. Leave input 1 assigned to the Zzero plate, and chose another one to mess with. I don't see why you couldn't set it up to function like a limit switch. You'' want to make sure that your metal box is well grounded to the machine itself so that you get continuity.

-B

[jong]

Thanks Brady

So should I connect a wire between the metal guard and the control box Input 2. And also connect a ground wire between the metal guard and the frame of the machine?

Or do I connect 2 wires at the metal guard and run them both to the control board input 2 and ground on the control board terminal?

[Brady Watson]

"So should I connect a wire between the metal guard and the control box Input 2. And also connect a ground wire between the metal guard and the frame of the machine? "

Yes & Yes. You only need one ground & the one for the Zzero plate should be adequate.

-B

[jong]

I connected the wire instead to INPUT 3 (prox switches) and the metal guard. Thus if the spindle contacts the guard its like hitting a prox switch. Works great!

The wire connected to INPUT 3 gives me 5.3V, 5mA at the metal guard so I think touching the spindle to the plate grounds this current.

Should I be concerned about the floating current to the guard?

[Brady Watson]

The same amount of current is probably @ your Zzero plate...So, no.

-B