Re: [CAD_CAM_EDM_DRO] Question Re: Work Offsets

So a G91 call will use the offsets I set using G92? (I'm guessing from
what Tim Goldstein wrote, and from some of the EMC changelogs, that this
is what EMC is doing when I right-click on an axis and set it to zero.)

I'm still puzzled as to why the behavior is different in MDI mode and AUTO
mode. Paint me as being ignorant, but I'd been assuming they behaved
exactly the same, regardless of which one was used to get the G-codes into
the machine.

Tom

On Thu, 12 Jun 2003, stephank97 wrote:

> Hi Tom
>
> IIRC you need a G91 in your G-code file. If you have homed your
> machine manually by jogging, use G91 as the first line. That should
> fix it. Unfortunately I do not have my EMC manual in front of me,
> just check the exact syntax.
>
> Stephan
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "inetd_conf" <benedict@h...>
> wrote:
> > I had some odd behavior on an EMC system running BDI 2.16:
> >
> > I spent the last two days PID tuning to get the axes running
> > cleanly. They're running cleanly now, and in the process I had
> the
> > opportunity to set up and run a number of toolpaths, mostly
> > prototyping in pine so a tool crash wouldn't be disastrous.
> >
> > Today I tried to run an actual part. I used an edge finder to
> > indicate in the workpiece, and set my zeros by right-clicking on
> > each axis in turn and setting it to zero.
> >
> > When I ran my program, it proceeded to crash the tool into the
> > workpiece (even though the first move is to go to (0,0,0) and
> raise
> > the quill to 2.0" off the top of the workpiece.)
> >
> > I carefully checked my zeros and loaded a new part. Same
> behavior,
> > only this time it snapped the end mill off.
> >
> > Before changing a tool and crashing it again, I played around with
> > it.
> >
> > In MDI mode, if I typed "G0X0Y0Z0", it would go to (0,0,0) in the
> > relative coordinate frame. If I ran the program, it would attempt
> > to go to (0,0,0) in the absolute machine coordinate frame (the Z
> > value of which was well inside the workpiece).
> >
> > I stripped the entire header off the program file so it starts
> with
> > that "G0 X0.000 Y0.000 Z0.000" statement. Same behavior.
> >
> > What am I missing here? I thought MDI and running a program was
> > essentially the same thing. I didn't know one would run in one
> > coordinate frame and one would run in the other. I'm REALLY
> puzzled
> > why this behavior didn't show up during the two days of PID tuning
> I
> > did.
> >
> > I could seriously use the help. I'm dead in the water, and not
> > really interested in busting any more tools or driving any cutters
> > into my vise or mill.
> >
> > Tom
>
>
>
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