What is in this article?:
- In Plasma Cutting, Science Matters
- Plasma Cutting Options, Advantages
- The fourth state of matter
- HF Contact or Pilot Arc
- Plasma gouging, too
Plasma cutting is gaining more industrial applications because it is efficient, and increasingly affordable.
Anyone working in a fabricating shop or machining operation comes face to face with a steady stream of science and technology every day. Speeds, feeds, calculations, and reactions — you have to be ready with the answer when the question arrives.
Some processes have been simplified to the point of pressing a button, but that doesn’t mean everything is easily understood. And thus, one of the most critical questions — What’s the right process for a cutting project? — may stump even the most informed operators.
In the case of a basic, but essential, process like metal cutting, there are various choices competing for manufacturers’ investment. Kerf Developments Ltd. offers a full range of cutting technologies — profile cutting, oxy-fuel cutting, waterjet cutting, and high-definition plasma cutting; it offered a tutorial in plasma cutting, rightly sensing that the technology is probably beyond the immediate understanding of many potential users.
It starts with a cutting gas — nitrogen, oxygen, argon, or even plain air. When the gas is heated to extremely high temperatures, the electrons in the gas molecules break free from the nucleus, turning the gas into plasma.
The plasma cutter directs that gas via a miniature orifice, which sends an electric arc through a gas stream. This heats the gas to the point at which it turns into plasma: The electrons collide and release energy, thus creating a very high volume of heat – and tremendous cutting capability.
Plasma cutting can be used to cut hard metals like steel, as with a plasma torch. In plasma cutting, inert gases as well as compressed air are blown at very high speeds and temperatures. On being heated, the gas is transformed into the plasma state.
This is generally referred to as the fourth state of matter, because its properties are distinct from solids, liquids or gases. The extreme heat that plasma has makes it an effective medium to cut right through metals. It also moves at a speed that is fast enough to blow all the molten metal from the cut.