Re: [CAD_CAM_EDM_DRO] Re: CNC'ing both quill and knee

Polaraligned wrote:

> 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

Different jobs may require different approaches, you could have two
setups, one using the quill as Z and the knee as W or reverse them if
different travels or other curcumstances appear. Ed.