Re: [CAD_CAM_EDM_DRO] VectorCam Demo and EMC - Lathe

I couldn't wait and set up the demo on my machine where I am right now.
Re-ran it, and found where I went wrong (or right, or whatever): I
selected the NC device to be a lathe. (My guess is a dedicated lathe
controller would assume all arcs are in the X-Z plane, so the G17/G18/G19
selection would be unnecessary.) DOH! So yeah, adding the appropriate
one made things work.

What I get for making a lathe out of a mill. I'm learning... I'm
learning... My bed-time reading for the night is the EMC Handbook and the
Numerical Control section of Machinery's Handbook.

Thanks again,

Tom

On Thu, 28 Feb 2002, Jon Elson wrote:

> Tom Benedict wrote:
>
> > I've got a Taig CNC mill with the Microproto controller. I got EMC
> > working fine with three axes (I'm having little to no luck getting the
> > fourth axis working, but that's neither here nor there.)
> >
> > Last night, just for grins, I turned the mill head 90 degrees, mounted a
> > lathe toolpost on my mill bed, and brought the spindle down until it was
> > level with the lathe tool. In effect I made my mill into a poor-man's CNC
> > lathe.
> >
> > I've got the VectorCam demo set up on a machine at home, and have been
> > trying it for mill work. But I've been wanting to test it for lathe
> > functionality, too.
> >
> > I ran into a problem. I'm hoping someone can help:
> >
> > I used a CAD package to draw up the profile of a ball handle (two arcs,
> > one tapered straight section, and the second arc was cut short so it
> > would leave the ball handle firmly attached to the stock.) The DXF
> > imported into Vector perfectly. I used the lathe pocket function to set
> > up a toolpath, saved it as NC code, simulated it, everything checked out
> > fine.
> >
> > There were two problems when I tried to run it using EMC. One was my
> > fault, one I'm not sure of. The one that's my fault was because I didn't
> > know CNC lathes use X and Z axes. After some time reading Machinery's
> > Handbook, I figured that out, swapped my motor plugs, and was back on
> > track.
> >
> > That's when I ran into the second problem: The roughing passes went
> > perfectly. The finishing pass died as soon as it hit the first arc. The
> > error message was something like, "K word on an arc in the XY plane."
> >
> > Far as I can tell, the G-code generated by Vector is spot-on. It had an X
> > word, a Z word, an I word, and a K word. The arc is in the X-Z plane, not
> > the X-Y plane.
>
> G17, G18 and G19 select the appropriate axis plane for arc motions.
> I always forget which is which, G17 is XY, of course. From the EMC
> help file, you need a G18 before that arc, to select the ZX plane
> for the arc.
>
> > Any idea how I can fix this? Is this an EMC thing? My EMC installation
> > is off the latest BDI.
>
> No, most CNC systems that support arcs in one of 3 planes require you
> to define the plane before the arc.
>
> > I'm probably not going to use my mill like a lathe very much (I'd rather
> > build out a dedicated CNC lathe), but I'd like to go ahead and buy Vector
> > next month, and I've got some short-run stuff I'll need to do with it in
> > this configuration. So any and all ideas are much appreciated.
>
> This should get you running.
>
> Jon
>
>
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