manual Z axis help/ideas wanted

[chris.poirier]

I have a ridged head knee mill with no way to manually run the quill.
Is it possible to add a hand wheel to run the servo while the e-stop is active?
What I want to do is keep Z active to run manually and not power x and y so I may use the machine manually for quick cuts.
I need some method other than running the knee up and down.
I toyed with adding a bevel gear under the servo with a shaft and a hand wheel but it will not stop someone from over running the limit switches and possibly damaging the ball screw.


Chris

[Centroid_Liviu]

Are you running Mach3 or CNC11? You wouldn't be able to use Estop because that takes all motor power away (at least on a properly wired Estop). We can provide some pointers (or a custom program) to use an aux key to free up the X and Y axes in Brains or a custom PLC but need some more info.

[chris.poirier]

I want to use CNC 11.
If Mach is the only way I might have to consider it in order to keep the DRO in manual mode.
My last ditch idea is to use the limit switches to activate a break on the back of the servo to keep from damaging anything but this will require double pole limit switches and a costly electric break, not to mention buying the materials and effort to make the gearbox for the z hand wheel.

3 electronic wheels to do x/y and z might work, Jog mode works on the MPG but how responsive is it?
Could I do this with cheap encoders and some PLC code with CNC 11?
Any pointers ideas are welcome.

Chris

[cncsnw]

What I want to do is keep Z active to run manually and not power x and y so I may use the machine manually for quick cuts.

I think you can already do this.

Use the F1/Setup -> F4/Feed -> F3/Free option to release power on X and Y. Alternately, just press E-stop, then release it again. The X and Y axes will be free to turn by hand.

Use jog buttons or the MPG handwheel to move Z. The control will enable the Z servo if needed, but X and Y will remain free as long as you don't try to move them with the jog buttons or handwheel.

[chris.poirier]

OK this is good.
Can I add a single hand wheel to run Z?
If so can I hack the design to make a handle similar to what you would see on the side of a Bridgeport head.
Also is there a way to get the % load of the z-axis servo out to the outside world?

I am a mechanical design engineer by day and have some electronics buddies willing to help me.
Call me crazy but if possible I wan to use current limited source to run a small DC motor to provide force feed back.
Chris

[cncsnw]

Can I add a single hand wheel to run Z?

Yes. See the MPG connector pin-out on your wiring diagrams or MPU11 or All-in-one hardware manual. You can probably make your MPG on/off switch close directly to the 3rd-axis select signal, so it is either off or controlling Z. You can hardwire the increment select too, if you don't want to provide a switch for that.

If so can I hack the design to make a handle similar to what you would see on the side of a Bridgeport head.

You can if you want. You just need a suitable encoder: 5V differential driver output, suitable line count (usually 100). You can add mechanical detents yourself.

Also is there a way to get the % load of the z-axis servo out to the outside world?

As far as I know, no. You would have to hang some sort of DC current sensor on the cable.