How Thick Can A Plasma Cutter Cut?

Plasma basics and when to consider using the process

Plasma is an electrically conductive ionised gas that is created by adding energy to an electrically neutral gas. The energy is electricity and the gas is usually compressed air. These two elements combine in the chamber between the electrode and the nozzle, causing the gas to become unbalanced, producing plasma gas. The air pressure forces the plasma gas through an orifice in the nozzle, resulting in a concise, electrically conductive constricted stream. The more energy added through the plasma cutter, the hotter the plasma arc becomes, thus providing higher cutting capacity and efficiency.

Plasma Cutter

Plasma cutters are used to perform cutting and air planing operations, and common handheld systems are capable of cutting metal thicknesses of up to approximately 1 inch. Plasma typically requires a compressed air source and a large amount of electrical power. These are issues to consider when the application requires portability, although the reduced size and weight of plasma machines - some of the smaller machines weigh around 20 pounds - makes them more portable than ever before. In addition, on many sites where engine-driven welders/generators are commonly available, the need for power is not an issue.

One of the biggest advantages of plasma is its ability to cut non-ferrous metals such as aluminium, stainless steel and cast iron, which are becoming increasingly common in many applications. Speed and precision cutting are also advantages of plasma, which typically cuts with minimal slag and can provide a much narrower, smoother cut than that produced by an oxy-fuel torch. 

The basics of oxy-fuel cutting and the benefits of the process

Oxy-fuel torches offer advantages in cutting thicker metals and in some cases can offer greater portability. Oxyfuel torches are also versatile as they are capable of cutting, welding, brazing, brazing, heating and air planing. Common handheld systems can cut steel from 6 to 12 inches thick. However, some flame handheld torches are capable of cutting steel over 20 inches thick. Oxy-fuel is not dependent on a primary power or compressed air source, so it can offer advantages for jobs that require a high degree of portability. Some small oxy-fuel systems weigh about 35 pounds, so with an oxy-fuel tank and torch, steel can be cut almost anywhere.

 Plasma Arc Welding Torch

Oxyfuel torches are typically only used for cutting ferrous or ferrous metals and in most cases not for cutting cast iron, aluminium or stainless steel. For thicker steels over 1", oxy-fuel torches are capable of higher cutting speeds than typical 100 amp handheld plasma cutting systems. In addition, certain operations are unique to oxy-fuel systems, including fusion welding, heat treatment, thermoforming, riser cutting, welding and brazing of ferrous metals.

When cutting with oxyfuel, the oxygen/gas flame preheats the steel to its ignition temperature. A high-powered oxygen jet is then directed at the metal, creating a chemical reaction between the oxygen and the metal to form iron oxide, also known as slag. The high-powered oxygen jet removes the slag from the cut.

When using an oxy-fuel torch, cut quality, preheating time and metal thickness can all be affected by the type of gas used. There are four basic fuel gases most often used in combination with oxygen in this process: acetylene, propane, propylene and natural gas. The choice of fuel gas is usually based on the cutting application, cost, heat output and oxygen consumption.