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

Stephen Wille Padnos 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

Be very careful when using parallel axis's as they may not be perfectly
aligned. Bore a hole while moving one axis then sweep the bore top and
bottom with an indicator using the other axis. Ed.