Re: 3D plasma/water-jet cutting

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Tom Foley" <tpf_ski93@...> wrote:

>
> Hi,
>
> I'm interested in plasma and/or water jet cutting on curved surfaces.
> The shape (mostly circles) would be controlled by the XY plane and the
> torch/nozzle normal to the XY plane (sort of a saddle-cut).
>
> Has anyone tried this?
>
> Can I control the torch to work distance accurately enough?
>
> Does the plasma torch need to be so close to the work that the surface
> curvature will interfere with it?
>
> Any ideas would be appreciated.

Tom, the success if this will be dependant on the steepness of the
curve. We have THC units where they are cutting 6" dia holes in 16
and 18" pipe. The THC will do its best to hold a constant height
above the material as it travels and if you have enoungh Z travel it
will cut partially down the sides. As the angle changes from the
vertical as you go down the sides, the torch has to start cutting off
the vertical at the tip (which it doesn't do well). If the angle gets
too severe the torch is cutting through much more metal and the tip
volts will change.

For smaller dia pipe you need to rotate the pipe and keep the head
locked in a the rotational plane.

I would think water jet would have similar problems but I don't know
how it reacts to cutting at an angle.

Last solution is to build a 4 axis on the torch head itself so you
could actually rotate the cutting tool and use the Tangential function
in MACH3 (Don't ask me how though because I have never done it!)

>
> Tom
>