Subject: Re: Torches

From: [email-masked] (Gene Olson and Chris Wilson)
Date: Tue, 7 May 1996 00:30:16 -0400 (EDT)

>Being more used to the steel torch (hacksaw) than gas torches I get sort of
>confused by some of the terms floating around.
>
>Could someone please tell me the difference between a laser torch and a
>plasma cutter?  I have heard both terms and after listening to their use in
>the shop I wonder if they are the same.

A lazer is a beam of coherent focused light photons marching in lock step.
The mild variesty makes a great pointer spreading from a 1/16th aparture to
3/16 at 50 feet. When you pump a lot of energy into the photons they come
out with a vengence and either melt, vaporize or burn their way thru
whatever is in the way. (almost, most industrial lasers use copper mirrors
ot ge the light to lase so when  you try to cut copper or bronze the metal
surface melts and the smooth molten copper surface reflects the light. Thin
puddle no cut.

Plazma on the other hand is made of atoms that have lost some of their
electrons. You may have heard of solar plazmas, or interstellar plasmas,
well they are first cousins. A plasma torch uses two electic circuits to
create and to focus a flow of very excited atoms that have been stripped of
some of their electrons and really really want em back. The two circuits are
between the center electrode and the metal cap on the torch and between the
torch cap and the work. Nitrogen or air (in some torches) is forced under
pressure between the cap and the center electrode. When you start the torch
it sends an electric arc through the gas and strips some of the electrons
off creating a gas plazma, at the same time this near instantaneously heats
the gas to close to 6000 degrees.
If you had physics/chemistry you may remember the gas laws and which say
that if the temperature goes up either the  pressure will go up uor the
volumn will increase. With a hole in one side and constant presuure coming
in the volumn goes way up and squirts out the hole in the torch at high
speed and close to 6000 degrees. The gas is a charged plazma, though and
because it is charged it is easily controled, focused by an electric field,
the difference between the torch and the work. this focuses the jet of
plazma at and thru the work where it melts the material away.

Ok Dr. Mark, did I get this one right

Gene

 The Studios of Gene Olson and Chris Wilson - Working in Metals, Stone,
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From: "Dr. Mark E. Williams" <[email-masked]>
Date: Tue, 7 May 1996 07:58:52 -0400

On May 7, 12:30am, Gene Olson and Chris Wilson wrote:
> Subject: Re: Torches

Sounds good to me. Lasers are used to put nice, smooth holes in diamonds in
very short times. When focused properly, lasers make a very small, very sharp
"knife" that will cut almost anything.

Plasmas fill fluorescent light bulbs and make up the Sun and most stars.

Mark

-- 
Dr. Mark E. Williams
Bldg N-159, Rm E-215
NASA/GSFC/WFF/EG&G
Wallops Island, VA 23337
804-824-1744
[email-masked]

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