Plasma is the fourth state of matter, following the more commonly known states of solid, liquid and gas. Plasma is effectively super-heated gas. When the gas reaches a high enough temperature, it becomes ionized and is able to conduct electricity. Plasma cutters utilize this phenomenon to cut any type of conductive metal. They direct a very thin beam of the ionized gas at the metal at temperatures of up to 30,000 degrees Fahrenheit (16,650 degrees Celsius), which melts the metal, cutting through it or into it.
Before beginning to use your plasma cutter, make sure that you are wearing protective clothing and eye shields. Check all consumables (the parts of the machine that get worn during use, such as the nozzle, electrode and gas baffle) and replace if necessary. When you're ready to start cutting, begin the pilot arc with the nozzle on or very near the metal. Within a few moments, the cutting arc will begin. Some plasma cutters have a system that automatically moves the nozzle away from the surface to be cut, while on other models, you will need to do this manually; if you leave the nozzle on the surface, it will be damaged. If you're just learning to use a plasma cutter, or if your hand is not completely steady, you can use a drag cup over the nozzle, or roller guides, which keeps the nozzle stable and at a fixed distance from the metal.
It's recommended to start the cut at a 60-degree angle and then move to 90 degrees once you can see sparks coming through the bottom of the cut. If you don't see the sparks, then you may not be cutting all the way through, and you will need to either slow the movement of the cutter to give it more time to melt the metal or increase the current. The necessary current and speed will be dictated by the type of metal you are cutting and its thickness. As you end the cut, angle the cutter inward and pause for a moment to ensure the cut finishes evenly.