Re: [CAD_CAM_EDM_DRO] VectorCam Demo and EMC - Lathe

Next datapoint:

I took everyone's advice, re-did the conversion to cast it in X and Y
coordinates rather than X and Z, and the K-word errors went away.

But now I'm getting this error whenever I hit the finishing pass:

emctask.cc 229: rs724mgc_Error: Radius to end of arc differs from radius to start

Here's the snippet of code that's creating this (I'll eliminate the
roughing bit, which is a bunch of linear G01 / G00 moves):

-----

N600 G00 X0.574 Y-0.357
N601 G01 X-0.095 Y-0.187
N602 G00 X-0.095 Y0.000
N603 G01 X-0.015 Y0.000
N604 G03 X0.196 Y-0.049 I0.109 J0.016
N605 G01 X0.503 Y-0.093
N606 G03 X0.578 Y-0.185 I0.090 J0.062
N607 G01 X0.578 Y-0.187
N608 G01 X0.522 Y-0.299
N609 G00 X-0.095 Y-0.299
N610 G00 X-0.095 Y-0.187
N611 G00 X-0.095 Y-1.762

-----

Fair warning, I haven't gone back to hit the books on this one. So if
it's an obvious error, bear with me.

Thanks,

Tom

(P.S. I got the scale on the part wrong, so it's not much to look at. As
soon as I get everything working right, I'll take pictures and post
stuff.)

On Thu, 28 Feb 2002, Tom Benedict wrote:

> On Thu, 28 Feb 2002, Alan Marconett KM6VV wrote:
>
> > I never thought of turning the spindle horizontal and using the
> > tailstock to simulate a CNC lathe! But then, I had my mill for 17+
> > years, and until recently, did not know or think about rotating the
> > spindle (it only has one key slot)!
> >
> > OK, you mounted the tool holder on the X axis, so no tailstock?
> > Still, I like the idea. I KNEW there was a reason I got the Sherline
> > 4-jaw chuck (and tailstock)! Maybe what is needed is a way to mount
> > the spindle ON the X axis, and then something else (on the z) would
> > carry the tool?
> >
> > I'm anxious to try this lathe setup! could you possibly email me the
> > DXF or CCD file(s) you are experimenting with? ;>)
> >
> > I'm sorry I can't help with the EMC question, but I believe the Vector
> > output is correct!
> >
> > Alan KM6VV
>
> Pretty sure it is.
>
> The "head sideways" thing on the mill is temporary. I've got a Taig CNC
> mill, and a Taig manual lathe (only kind of Taig lathe, unless you do the
> CNC conversion yourself.) I made an adapter plate that will let me mount
> my Taig lathe on the mill bed.
>
> The eventual mad scientist plan is to mount my Sherline rotary table on
> the mill column, mount the Taig lathe on the mill bed, and have a CNC
> turret lathe. Tool bits would be indexed by rotating the rotary table,
> and the work would be mounted on the lathe (complete with tailstock.)
>
> The "head sideways" thing was basically a test to see if I could. And for
> face milling, I think it would be a much less invasive way to set this up.
> But eventually I'd like to use this setup to machine custom gear cutters,
> so yeah, a tailstock would be a huge huge plus.
>
> (Besides, if I can get a CNC lathe for the price of a chunk of aluminum
> and four mounting screws, I figure that's not a bad deal.)
>
> Tom
>
> > 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.
> > >
> > > Any idea how I can fix this? Is this an EMC thing? My EMC installation
> > > is off the latest BDI.
> > >
> > > 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.
> > >
> > > Thanks,
> > >
> > > Tom
> >
> >
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