What Is Plasma Cutter, Types and Working

Plasma cutters are commonly used for cutting different metals using plasma arc. It has a high-frequency power supply that sends an electrical charge to the metal object to be cut. This is done by generating a steady stream of ionized gas particles that form a plasma, as it travels from the nozzle of the cutter to the object being cut. 

It produces a more accurate and efficient way of cutting metals as compared to conventional methods like chipping saws and abrasive cutters. A general Plasma Cutter usually runs on 220 volts at 50 Hz or 60 Hz, depending upon the country where it is manufactured and sold (50 Hz in Europe and Asia and 60 Hz in North America and some other countries).

Plasma Cutter has a small semicircular window at the top where it shows how much it is being used during operation. A red color bulb means that the Plasma Cutter is on standby mode, green color means it is ready for operation. Plasma cutters are battery operated, with batteries ranging between different manufacturers. 

 Plasma cutters come with a standard power rating of 100 amps up to 500 amps, which is capable of cutting almost all kinds of metals. A plasma cutter has a nozzle that produces a plasma arc that is further converted into heat, by transferring its kinetic energy to the molecules in the metal.

Plasma Arc torch consists of two electrodes i.e., cathode and anode which acts as an ionizing gas chamber where gas filled inside it gets ionized and forms plasma arcs at the end of the nozzle.

A Plasma Cutter makes use of Plasma produced from gases like oxygen (O2), nitrogen (N2) and hydrogen (H2) through air or pure argon (Ar).[1] The choice of which gas should be used depends on the material to be cut, for example, a Plasma Cutter which is used to cut mild steel uses Plasma produced from Air or mixed gases of air and Argon.

The process of Plasma Arc starts when an electrical arc is struck between the cathode (negative electrode) and anode (positive electrode). This initiates a chain reaction called Ionization Process which releases super heated ions that result into Plasma formation. The atoms get ionized through various processes like Collision Ionic Absorption, Photoionization, Secondary Emission etc.

The Plasma Arc Cutting process is governed by two different types of Plasma i.e., "Dark Plasma" formed due to resistance against the cut, and "Bright Plasma" which emits light energy that results into plasma cutter flame seen during cutting. The metals are heated up to high temperatures, resulting in formation of molten metal vapor along with hot dust particles which are ejected out from the other side of the Plasma Torch nozzle at very high speed. Maintaining Plasma Cutter requires changing gas cylinders, electrode/tips, AC capacitor plates, AC frequency plates etc.

A new process called Air Plasma Cutter has been developed by different manufacturers which makes use of air itself instead of using additional inert gases like Argon and Nitrogen. 

All these types of Plasma Cutting Machines can be used on various job sites, however Plasma Cutters are mostly used in Plasma Arc Cutting Applications in engineering industries, Plasma Arc Cutting Applications in marine industries, Plasma Torch Cutting Applications in automotive or shipbuilding industries and Plasma Arc Cutting Jobs at construction sites.

Guest Contributor: Damaso Sanoja