Re: CNC'ing both quill and knee

Thanks Stephen,
I know what the axis is supposed to be called now!
I knew A,B and C were circular motions.

My idea with the knee anyway is to eliminate the not so friendly
crank and be able to move it in a precise increment, or even be
able to use the knee as the "Z" axis instead of the quill if the
part being machined requires the extra travel. Using them in
concert with each other would be good if they are in reasonable
alignment as Ed pointed out, and the software allows.

I guess the best thing to do is mount the servo motor and wire the
knee as a separate "W" axis. That seems to allow me the most
flexibility.

Thanks,
Scott





--- In CAD_CAM_EDM_DRO@yahoogroups.com, Stephen Wille Padnos
<spadnos@...> wrote:

>
> Polaraligned wrote:
>
> >Have a Series II CNC that I am converting. Not my first as I have
> >already done a Series 1 machine.
> >I am looking to do a 4 axis conversion on this machine. So far I have
> >never needed more than the 5" travel of the quill. So the quill will
> >have the stepper replaced with a servo and be my primary Z axis. I
> >would also like to use the knee like a 2nd Z axis to give me more Z
> >travel. The knee should work nice as it is air assisted and has large
> >box ways. So....is it possible to make the quill and knee work in
> >concert with each other? Should I just make the knee another axis,
> >say the B axis, and worry about how it will work with the software
> >(mach 3) later?
> >
> >
> The G-code definition of that axis is "W". U, V, W are defined as
> linear axes that are parallel to X, Y, Z respectively.
>
> I don't know of any controller (EMC2, Mach, DeskCNC, TurboCNC) that

will

> automatically move one motor or the other. I know for sure that EMC2
> can handle all 9 G-code axes (XYZABCUVW), I don't know how the others
> would need to be set up to do that.
>
> One trick that can be useful is to move the knee for tool offsets (EMC2
> has an option which will put offsets on the W axis instead of Z - it's
> meant for 5-axis machines where the tool is tilted, but it works when W
> is always parallel to Z also). This allows you to use the full quill
> travel regardless of the length of the tool.
>
> - Steve
>