How Does a Plasma Cutter Work?

Introduction

There are three states of matter encountered in everyday life, and a fourth that is not as common. These exist as water, solid and gas--with the last being plasma. Almost 99 percent of all matter in the universe is plasma, however it is not as common on earth because it exists at extremely high temperatures. We are more likely to see it in the sun or in the form or lightning. Plasma is also used in neon and florescent lights.

States of Matter

To understand where plasma fits in, first look at the states of matter in the world and its properties. The atom is made up of neutrons and protons in the nucleus surrounded by a cloud of electrons. When super heated, these electrons move very quickly in random patterns and are released from their bond to the nucleus. When the electrons leave their bond to the atom, they are negatively charged and leave behind positively charged nuclei known as an ions. The hotter the electrons get, the faster they move and when they collide they release vast amounts of energy.

Examples

Using water as an example, the first state of matter is a solid. A solid has a definite shape and is made up of neutrally charged atoms arranged in a hexagonal pattern. Ice is a good example. Liquid is the next state of matter. In this state the molecules are still bonded together but move relative to each other very slowly. Gas is the next state in which the molecules move around at a high speed independently from one another and separate, leaving the negatively charged electrons and positively charged nuclei known as ions. Plasma is formed as the last state of matter where the electrons and ions are moving so fast that when they collide with each other they produce huge amounts of energy.

Plasma Cutting

A plasma cutter uses this energy to its advantage. It has a nozzle with two passages for gas and a center negative electrode. When it is charged with electricity and held close to the metal to be cut, it creates a very hot spark. A gas such as argon flows from the closest passage surrounding the arc which is extremely hot and causes the molecules to move a an extremely accelerated rate, colliding into each other and releasing a great amount of energy. To contain the unpredictable arc within a small confine a second passage flows a shielding gas. The plasma builds to an incredible 30,000 degrees--capable of cutting almost anything. It can cut through thick sheets of metal like butter.