Naked Science Forum
Non Life Sciences => Technology => Topic started by: chris on 26/01/2012 03:29:33
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These devices can be used to cut through metal - but how does this actually work?
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I don't know, but I wish they were not so expensive.
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Like everything, there is a good Wikipedia article.
Compare:
Carbon Arc Gouging (http://en.wikipedia.org/wiki/Air_carbon_arc_cutting)
Plasma Cutting (http://en.wikipedia.org/wiki/Plasma_cutting)
Here is also a good explanation of the Plasma Cutter on How Stuff Works (http://home.howstuffworks.com/plasma-cutter4.htm) with a simple animation. Also see link with illustration.
In Carbon Arc Gouging, one makes an arc between an electrode and a piece of metal. The compressed air is then used to blow out the metal.
In Plasma Cutting, the negative electrode is up inside the plasma cutter, with the work being positive. The arc is essentially carried by the cutting gas, usually compressed air, which superheats the air and turns it into a high temperature, high pressure plasma. Apparently some of the higher grade torches may use other cutting gases.
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Plasma cutters are fast, I used one to cut up an old tank that was too big to get out without doing a lot of building work, and it was reduced to scrap stainless plate in under 20 minutes. I suggested one to the metro contractors removing old poles for refurbishment, as they had spent 4 hours with an acetylene cutter to remove one - century old steel pole that was near an inch thick at the base they were cutting. Impressive to see how much the street had risen from roadworks in a century, the concrete base was over a metre down in the hole. They rented one and took the rest down in a day. The poles came back later, powder coated and with a new base plate, bolted to a new foundation cast in situ - a steel frame 1m by 1m by 1m that needed around 9 tons of concrete poured in to it to get the level. Now they are doing what they originally did - steel spanwires with lights on them in the middle of the road, as originally they were used to hold up power cables for trams.
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There is some info and video's here:
http://www.kerfdevelopments.com/plasmacutting.html
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[quote link=topic=42906.msg378803#msg378803 date=1327554954]
Like everything, there is a good Wikipedia article.
Compare:
Carbon Arc Gouging (http://en.wikipedia.org/wiki/Air_carbon_arc_cutting)
Plasma Cutting (http://en.wikipedia.org/wiki/Plasma_cutting)
Here is also a good explanation of the Plasma Cutter on How Stuff Works (http://home.howstuffworks.com/plasma-cutter4.htm) with a simple animation. Also see link with illustration.
In Carbon Arc Gouging, one makes an arc between an electrode and a piece of metal. The compressed air is then used to blow out the metal.
In Plasma Cutting, the negative electrode is up inside the plasma cutter, with the work being positive. The arc is essentially carried by the cutting gas, usually compressed air, which superheats the air and turns it into a high temperature, high pressure plasma. Apparently some of the higher grade torches may use other cutting gases. These illustrations show a shielding gas. I don't know if all plasma cutters use it.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.plasma-cutter.com%2Fplasma_process.jpg&hash=11236fdb8ae38580fa2f3817d0ebf6a8) (http://www.plasma-cutter.com/technical.htm)
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Just want to ask a question. I know plasma cutter work by sending pressurized gas. But, which gas(O,Ni,Ar) is better and why?