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Author Topic: XY and Z zero  (Read 18590 times)

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Re: XY zero
« Reply #10 on: June 05, 2009, 02:45:03 PM »
I can`t thank you enough Ray - it`s working :-)

But the Vise X - why does it touch the same side of my material twice? There is only 1 zero point.

Edge Finder:  http://www.youtube.com/watch?v=XwOuTb0O1_Y&feature=channel_page

Vise X:    http://www.youtube.com/watch?v=4rtn5gTvzeU

Center finder:   http://www.youtube.com/watch?v=-UUwVK6FYN0&feature=channel_page


Adam


Adam,

It's for aligning the vise to a machine axis.  For instance, if you're setting the vise so the fixed jaw is parallel to the X axis, it first locates the left-front corner of the fixed jaw in both X and Y, and zeroes to the DROs to that corner.  Then it goes to the far right-hand end of the fixed jaw, and checks where it is in Y relative to the first end.  The status line displays how far out of alignment the jaw is.  So, if it indicates the mis-alignment is +0.010", that means the right-hand end of the vise is 0.010" further back (towards the column) than the left-hand end.

If you've completely milled away the top face of the part, then you can re-zero to the new surface, and either adjust your code for this new zero datum, or, after letting the macro zero to the new top surface, manually re-set the Z DRO to the true Z dimension (for instance, -0.010" if you had removed 10 thou).  It's also sometimes handy to set your zero reference to the bottom of the part instead, so it doesn't move if you face the entire top surface.

Regards,
Ray L.
Regards,
Ray L.

Offline simpson36

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Re: XY zero
« Reply #11 on: June 06, 2009, 06:17:39 AM »
Himy,

Your probing stuff looks really handy.

Where does one find the 'Files' section of the group. I'm sure it's in front of my face, but I can't find anything.

Thanks,


Offline kak

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Re: XY zero
« Reply #12 on: June 06, 2009, 10:05:50 AM »
Thanks again.

Is it possible to make some kind of Offset from my "job Zero point" to a location where I always be changing tools? That will be the best way to do it but I don`t know how.

Adam

Ps. Simpson36 - its in the Yahoo Groups. Look at Mach support window.
Re: XY zero
« Reply #13 on: June 06, 2009, 10:22:02 AM »
Thanks again.

Is it possible to make some kind of Offset from my "job Zero point" to a location where I always be changing tools? That will be the best way to do it but I don`t know how.

Adam

Ps. Simpson36 - its in the Yahoo Groups. Look at Mach support window.

It's certainly possible - you can do almost anythig with macros.  But I don't understand exactly what it is you're proposing.  Ordinarily you touch off on the part to establish your zero point, then use fixtures if you want to offset from there.

Regards,
Ray L.
Regards,
Ray L.

Offline simpson36

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Re: XY zero
« Reply #14 on: June 06, 2009, 12:32:22 PM »
Thx, had to join that group. Waitiing to be 'approved'  ::)

Offline Hood

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Re: XY zero
« Reply #15 on: June 06, 2009, 12:36:59 PM »
Just downloaded them and uploaded here to save you waiting ;D
Hood

Offline simpson36

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Re: XY zero
« Reply #16 on: June 06, 2009, 02:33:07 PM »
Thanks, Hood!

Got it!

Offline kak

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Re: XY zero
« Reply #17 on: June 06, 2009, 06:46:27 PM »
Sorry Ray. I just can´t understand this. I don`t know enough about cnc.

I think I will leave some part of my material unmilled, so I will still be able to Zero the top surface before the finish pass with ballmill.
I just want to make the wing mould when I`m ready for it.

Adam

Offline simpson36

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Re: XY zero
« Reply #18 on: June 07, 2009, 08:48:49 AM »
Kak,

It's not complicated, instead of starting at the top surface and using negative coordinates, you simply start at the bottom and all coordinates are positive, which is actually more intuitive, in my experience.

'Zero' is used as a noun and also as a verb in machining, so those darn semantics get in the way again . .  i.e. 'zeroing' (verb) is  just a term used for the process of telling the CNC machine where stuff is and it does not necessarily involve the number zero (noun) at all.

Example: Let's say your stock is .75"  . . grab your PC board and do the the tool height thing with the Himy stuff and what do you have? You have the end of the tool .75" (material thickness) plus .125" (the PC board) above the bottom of the stock. All you need to do is tell Mach3 where the tool currently is. There is no rule that says you MUST get the tool to 0.000 and then tell Mach it is at 0.0000. Mach just needs to know the coordinate of the CURRENT position and it will know where everything else it from there. 

In the example, if you want the bottom of the material to be zero, then the tool is currently sitting .875" above that, so you simply tell Mach where it is by typing positive .875 in the DRO and your good to go. You do not have to have the tool physically at zero on any axis. 'Zero' (the noun) is simply a reference plane from which the coordinates are all taken. It could be on the roof or 100 feet underground.The only caveat is to remember that you physically hit something at positive .875 in our example, so don't get absent minder (like me) and pick up the tool to say .5" for a rapid move or  :'(

 






« Last Edit: June 07, 2009, 09:21:44 AM by simpson36 »

Offline kak

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Re: XY zero
« Reply #19 on: June 07, 2009, 03:46:47 PM »
Thanks simpson.

It`still hard for me to understand it, but I have only read your last post 10 times :-)

The first line you wrote about starting at the bottom - is it something you do with the CAM software or Mach3?  The Gcodes starts at the bottom or the tool is touching the bottom when it´s zeroed?

Because I think that if I set the Z zero at the bottom of my material, the machine wil try to mill my table. But it can`t  - thanks to limit switches.
I think my coordinates are always positiv, but I didn`t play enough with different settings.

I don`t know how the professional Cam software works, but I`m using Meshcam. If I generate the Gcodes, I can save them one by one. f.ex. first Rough and then Finish. When the rough pass is over with an endmill I load the Finish pass Gcodes, but I need to change tool to a ballmill first. The "start point" for both passes is the same, but my ballmill is maybe longer then my endmill.
And because the top surface is milled away during the roughing pass, I can`t zero the ballmill. The ballmill needs to be zeroed on top of the material surface, which is gone.

Thats where I am now, but I need to try this Zero at the bottom next time.

Adam