Plasma Cutter
What is plasma?
To properly explain how a plasma cutter works, we must begin by answering the basic question “What is plasma? In its simplest terms, plasma is the fourth state of matter. We commonly think of matter having three states: a solid, a liquid, and a gas. Matter changes from one state to the other through the introduction of energy, such as heat. For example, water will change from a solid (ice) to its liquid state when a certain amount of heat is applied. If the heat levels are increased, it will change again from a liquid to a gas (steam). Now, if the heat levels increase again, the gases that make up the steam will become ionized and electrically conductive, becoming plasma. A plasma cutter will use this electrically conductive gas to transfer energy from a power supply to any conductive material, resulting in a cleaner, faster cutting process than with oxyfuel.
The plasma arc formation begins when a gas such as oxygen, nitrogen, argon, or even shop air is forced through a small nozzle orifice inside the torch. An electric arc generated from the external power supply is then introduced to this high pressured gas flow, resulting in what is commonly referred to as a “plasma jet”. The plasma jet immediately reaches temperatures up to 40,000° F, quickly piercing through the workpiece and blowing away the molten material
About the tool:
Plasma cutting is a process that cuts through electrically conductive materials by means of an accelerated jet of hot plasma. Typical materials cut with a plasma torch include steel, Stainless steel, aluminum, brass and copper, although other conductive metals may be cut as well. Plasma cutting is often used in fabrication shops, automotive repair and restoration, industrial construction, and salvage and scrapping operations. Due to the high speed and precision cuts combined with low cost, plasma cutting sees widespread use from large-scale industrial CNC applications down to small hobbyist shops.
The basic plasma cutting process involves creating an electrical channel of superheated, electrically ionized gas i.e. plasma from the plasma cutter itself, through the workpiece to be cut, thus forming a completed electric circuit back to the plasma cutter via a grounding clamp. This is accomplished by a compressed gas (oxygen, air, inert and others depending on material being cut) which is blown through a focused nozzle at high speed toward the workpiece. An electrical arc is then formed within the gas, between an electrode near or integrated into the gas nozzle and the workpiece itself. The electrical arc ionizes some of the gas, thereby creating an electrically conductive channel of plasma. As electricity from the cutter torch travels down this plasma it delivers sufficient heat to melt through the workpiece. At the same time, much of the high velocity plasma and compressed gas blow the hot molten metal away, thereby separating i.e. cutting through the workpiece.Plasma cutting is an effective way of cutting thin and thick materials alike. Hand-held torches can usually cut up to 38 mm (1.5 in) thick steel plate, and stronger computer-controlled torches can cut steel up to 150 mm (6 in) thick.[1] Since plasma cutters produce a very hot and very localized "cone" to cut with, they are extremely useful for cutting sheet metal in curved or angled shapes.
Safety:
Proper eye protection and face shields are needed to prevent eye damage called arc eye. Leather gloves, apron and jacket are also recommended to prevent burns from sparks and debris.
Videos:
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