Re: [CAD_CAM_EDM_DRO] Re: Laser links ?

> Using a CO2, I seem to remember that the cut is continuous and the
> material is vaporized. A small jet of air is used primarily to remove
> the vapors as they are a detriment to fine focusing, the secondary
> effect of the air jet is cooling. Don't forget that the kerf is very
> narrow.

CO2 is continuous as you say. The jet of gas is used to remove the material
from the cut, like the oxygen in an oxy/acet torch or the nitrogen in a
plasma cutter. Without the gas you would need one super huge laser to make
the cut and then it'd be of very poor quality. The laser is simply there to
heat the part. Indeed, I am curious as to why they are used in place of
plasma cutters on metals. The only slight advantage they may have is a
tighter heat dissapation area. Obviously they come into their own when
cutting non-metals since the part need not be conductive. In these cases you
must use an inert gas to stop the material burning in the air, now like the
shrouding on a MIG gun as well.

It is very possible to excite CO2 using RF and microwaves, in fact, I have
been reading a discussion on doing this since microwaves are so easily
obtainable at the dump. It'd be a good way of building a cheap laser gantry.
However, I have spoken to guys about this who question it's availablility to
hobbyists. First you have a number of problems with wave nodes etc and phase
differences when coupling emittors. Second, you need a seriously high
microwave intensity to make a gas under moderate pressure brake down into a
cold discharging plasma (What you need for a CO2 laser).

This is slowly drifting away from the CNC topic but I must say I'm posting
this junk because a laser gantry is a project that'd definitly be open for
some hobby CNC guys to work with.

John H.