What Components Make Up a Plasma Cutter?

Power Supply

Powered from the electrical grid, it generates direct current (DC) with a voltage between 240 and 400 V.
The total rated power and current capacity of the power supply have a crucial impact on the maximum cutting thickness.
Its primary task is to provide sufficient energy to initiate the arc.

Arc Starting Circuit

Typically a high-frequency generator circuit that produces an alternating voltage of 5–10 kV at around 2 MHz.

Torch

Holds the nozzle and electrode and provides cooling. It is the main component responsible for generating and directing the plasma arc.

Ground Clamp

Attached to the workpiece to close the arc-starting circuit between the torch and the material being cut.

Operating Principle

Different ignition methods exist. Air-plasma torches use either a moving electrode or a “blowback start” system to ionize the gas. In handheld plasma cutters, simply touching or approaching the workpiece with the nozzle is enough to initiate the arc.

With the ground clamp attached to the material, the arc is struck between the internal electrode and the workpiece.

The high-energy arc is sustained by a stream of compressed gas—typically air—forced through a narrow orifice in the nozzle, which focuses the plasma jet.
The gas is directed in a swirling pattern along the inside of the nozzle, allowing the formation of a plasma stream as narrow as 1 mm.

The torch is cooled with gas or water, depending on the system design.

Cross-sectional diagram of a plasma cutting torch showing the electrode, nozzle, and plasma arc flow used to generate and direct high-temperature plasma for cutting metal.

Both the nozzle and the electrode are consumables and must be replaced when worn.

Cutting Process

Cutting relies on extremely high temperatures—from 10,000 to 30,000 K—and the very high velocity of the plasma jet.
The material is melted, oxidized, and expelled from the kerf, which is very narrow. The resulting edge is smooth and typically requires minimal finishing.

Plasma cutting works on any electrically conductive material, even if painted. The only requirement is to ensure a clean contact surface for the ground clamp.

Plasma cutting is ideal for:

  • carbon steel

  • cast iron

  • stainless steel

  • aluminum and its alloys

  • brass

Safety Guidelines

Here are several important recommendations for safe operation of plasma cutting systems:

  • Protect yourself from burns—plasma cutting involves extremely high temperatures.

  • Use respiratory protection and ensure proper ventilation.

  • Shield your eyes and face from intense UV radiation.

  • Avoid unnecessary exposure to electromagnetic fields generated by the system’s electrical components.