How to zero a rotary axis

[jeffrey001]

Hi, would like to know how do you home your 4th Axis.

I'm not sure if a limit switch could be fine tuning enough to get good result.

I'm not sure either with an infrared device like a spindle indexer.

So how do you get good result when zeroing your 4th Axis.

Thanks, Jeff

[HuFlungDung]

If you mount an encoder on the motor, you should be able to home using a combination of the limit switch triggering, to then begin a 'find index' routine to find the encoder marker pulse.

If you want to do this manually, I suppose you could drill and bore a small hole in the edge of the table platter. Then use a dial indicator to sweep to find the hole center after you have already centered the table under the spindle.

Then, command a G92 A0 to zero that axis.

[Herbertkabi]

Absolute Encoder does not?
Regards,
Herbert

[Herbertkabi]

hi again,
Sad not any good ideas about

Anyway - How to zero a rotary axis,

Look at this Protractor:
MINI DIGITAL PROTRACTOR INCLINOMETER ANGLE FINDER GAUGE | eBay
How it works ???
Perhaps could be used for zeroing rotary axis when base of machine is well levelled Hopfully there is possible to get signal output ( or not ???)
For this idea the main problem for me is that machine itself must to be accurate levelled ... my machine need to be a little bid inclined for coolant drainage
Any more ideas?

I do not believe any limit switches can find precise zero ... vertical or horisontal ...or what

Yes, when zero once found then rotary decoder does the rest during all the work but specifically this first perfect zero finding before each work - this is very boring at least for me.

cheers,
herbert

[RomanLini]

Herbert- Have a look at this thread;
http://www.cnczone.com/forums/open_s...made_easy.html

It shows some simple home switches that will measure to about 0.01mm, and also have the advantage that they can "slide by" the zero point so they will not interfere with continuous rotation. And they have no moving parts to wear out.

I have these home switches on my machine and they are so accurate I can see tiny changes caused by the machine warming up and expanding.

[michaelthomas]

That's a very good thread......thanks!