How Does A Plasma Cutter Work?
Essentially the way a plasma cutter can cut-through metal comes down to the bare elements of the metal itself. Anything that is made from metal can be a conductor—the same reason we use metal for electricity since it travels through it so easily. Your electrical extension cord, for example, has long strands of copper wire running through it. When you plug it into an electrical socket, electricity travels through the cord to the other end.
A plasma cutter works similarly but instead uses compressed air and special gas. It will produce a plasma reaction that can cut right through the metal. But it needs to have both a positive and negative connection on the metal before it works. A metal piece being cut will need to be grounded directly from a clamp that comes from the plasma cutter. This connection is positive, while the actual cutter itself is negative.
Hence the connection between the two completes a circuit and allows the plasma to shoot through a piece of metal. In a nutshell, this plasma stream is electrically heated to increase the flow of electrons in one direction. On a microscopic level, it essentially eats through the metal like a knife cuts-through warm butter. The direction of the plasma flow is so strong it usually leaves a polished edge where it was cut. So, with that being said, let’s find out what a plasma cutter can cut so easily.
What a Plasma Cutter Can Cut
Any kind of metal that is electrically conductive is well suited for using the plasma cutter. You can cut these kinds of metal from a sheet metal thickness of 1-2mm up to 1-2 inches. Anything thicker is going to be tricky. Even for the automated plasma cutters, the thicker a metal tends to be, the more hazard from all the sparks that are produced. Even with thin metal being cut, you need to think of your safety first. The kinds of metal that fall into this category include:
- Mild Steel
- Stainless steel
- Carbon steel
- Copper
- Brass
- Aluminum
- Expanded steel
Gas Selection
Depending on the thickness of the metal, certain types of gas will need to be used to create higher temperatures of ion plasma that can cut through special types of metal. For cutting thick aluminum, you would typically use Argon and Hydrogen gas mixtures. When cutting mild and carbon steel, then pure Oxygen is used. Thin stainless steel would need Methane and Nitrogen.
Depending on the gas mixtures, many companies can save money on mixing their gases and still get excellent cutting quality. It’s safe to assume that all plasma cutters work well with only pure Oxygen. Operating a plasma cutter requires that you know about these kinds of gases and how they work. Needless to say, welders go through schools to learn the basics. Without any of this knowledge, you might find yourself at risk of being injured, burned, or setting your garage on fire!
What a Plasma Cutter Does Not Cut
It sounds like this would be an ideal replacement for conventional saws for cutting plastic and wood. Unfortunately, these objects are not conductive and cannot be cut by the plasma cutter. But some kinds of metal are terrible conductors. One metal called Manganese is awful for electrical conductivity. It has the same properties for connecting electricity as ceramics do.
There is also Bismuth and Tungsten that are very poor conductors of electricity too. Others include lead, tin, gallium, indium, thallium, ununhexium, ununpentium, ununquadium, and ununtrium. While these are often rare and exotic alloys, you’ve probably heard of tin, lead, or tungsten. Lead tends to splatter from the heat involved and can be very messy and a hazard too. Tin is a troublesome metal to cut, and the results are very poor.
Tungsten is the hardest to cut and needs professional equipment to cut it properly. Other materials that cannot be cut include glass, concrete, and ceramics. These materials are non-conductive and are used to insulate electrical products. If you are using a plasma cutter, it simply needs to have a conductivity to complete the electrical connection. Otherwise, it just won’t cut at all.