Re: CNC HOT WIRE FOAM CUTTING

How would it work to make a ceramic sleeve to chuck in the spindle.
The sleeve would have, say, a 1/16" dia. "nail" dropped in from the
top side of it prior to chucking. Heat the nail with a small torch
and then run the cut program at very quick speeds before it cools.
I'm talking a very small part here.
Nelson

--- In CAD_CAM_EDM_DRO@y..., ccs@m... wrote:
>
> > Hello all--wondering if anyone has any ideas on cutting foam with
a
> > stiff hot wire "chucked" in the spindle. I'm needing to make a
few
> > small "doughnuts" out of foam rubber less than 1/2" thick.
>
> Model airplane folks make new slightly longer tips for soldering
guns
> (the kind that have a heavy wire restiviely heated, not the
> pencil-like irons) to cut foam details after cutting the basic shape
> with a long thin heated wire.
>
> You might be able to make such as a milling tool, but would need to
> figure out how to couple high currents to the rotating spindle.
> (Don't do it via the bearings!) Some nifty method could probably be
> worked out using a sort of transformer, or even winding a generator
> armature and using the spindle to rotate it in a magnetic field.
>
> But I'd be more tempted to figure out how to put the work on a lathe
> where the heated tool need not rotate. Or use a boring head in a
> mill, but rotate the spindle by hand with some long flexible wire
> leads. I guess if you have a CNC that can do circule interpolation
> and manage to make a round cutter somehow the spindle need not
rotate
> at all. But a round tool would either need to be coaxial (in which
> case the inside may get hotter than the outside) or complete the
> current path via something below the work.
>
> Use adequate ventilation as the fumes may be very bad from some
types
> of foam rubber and have an appropriate extinguisher on hand in case
> you manage to set it on fire!
>
> Chris