Plasma cutting is a metal cutting technique that uses a hot plasma jet to cut electrically conductive materials. Plasma is a collection of charged particles that, in the form of an ionized gas jet, can generate temperatures over 200000 degrees Celsius, melting the material to perform the cutting operation. The plasma is constricted through a small orifice during the plasma-cutting process, increasing the velocity to form a jet and blow through the metals under consideration. Plasma cutting is widely used to cut carbon steel, aluminium, stainless steel, copper, brass, Monel, cast iron, titanium, etc.
What is Plasma?
Plasma is a state of matter in which particles exist as an ionized gas. It is the fourth state of matter, following solids, liquids and gases. Plasma is composed of free-floating ions and electrons that are highly charged. It has unique properties make it different from other states, such as its ability to conduct electricity and react to magnetic fields. In nature, plasma can be seen in lightning bolts or solar wind on Earth’s atmosphere. In industry and tech applications, plasma is used for various purposes, including welding torches and medical treatments like laser surgery or cancer therapy.
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What is the Procedure for Plasma Cutting?
As a thermal cutting method, plasma cutting uses high heat to melt the metal. A plasma cutter passes an electric arc through a constricted opening in the plasma gas. Air, nitrogen, argon, oxygen, and other common gases are plasma gas. The metal under consideration becomes a part of the circuit, and the plasma’s electrical conductivity transfers the arc to the workpiece.
A plasma-cutting torch employs a copper nozzle through which the gas stream containing the arc is transferred to the workpiece at a high velocity. The metal cutting operation is accomplished through high temperature and velocity. The arc’s heat melts the metal, and the gas jet removes the molten metal from the cut. Shielding gases are used for defence. Helium, nitrogen, argon, or a mixture of these gases are common shielding gases.
Plasma cutting is one of the most effective ways to cut thin, thick conductive materials. Hand-held plasma
torches can cut metals up to 1.5 in thick, while computer-controlled plasma torches can cut metals and alloys up to 6 in thick. Plasma cutters generate a very hot and localized “cone” to cut the metal and have high cutting speeds. However, the process usually produces a lot of noise.
Plasma Cutter Temperature
The temperature of the plasma cutter is extremely high. The plasma cutter’s temperature ranges from 200000C to 250000C. As a result, the safety of workers at the workplace is critical. Because of the high plasma cutting temperatures, the operation must be handled cautiously and use all PPE.
Cutting Speeds for Plasma Arc Cutting Process
The cutting speed of the plasma cutting process should be as fast as possible for economic reasons. However, for each type and thickness of the material, there is an optimum speed range for a specific electric power and gas mixture—excessive speed results in a narrower kerf. For manual control and complicated cuts, one m/s is a reasonable speed.
Depth of cut for Plasma Cutting Process
The plasma cutter’s amperage determines the plasma cutting machine’s cutting ability. A low amperage plasma can easily cut to a depth of 6mm. High amperage machines are required for cutting thicker materials.
How to use a Plasma Cutter
A plasma cutter is a machine that aids in metal cutting. Electricity is required to generate the plasma and arc required for cutting. The operation of a plasma cutter is simple. The following are the steps for using a typical plasma cutter:
- Connect a suitable air compressor to the plasma cutter.
- Connect the machine to a 240V or 415V power supply, depending on the cutter’s specifications.
- Connect your workpiece to the earth lead.
- Connect the plasma cutting torch to the machine next.
- Set the cutting amperage based on the thickness of the material.
- Finally, please turn on the torch handle and move it across the workpiece to achieve the desired cut profile.
Benefits of Plasma Cutting
Plasma cutting is one of the most effective ways to cut conductive metals and alloys. The following are the primary benefits of plasma cutting:
- Capability to cut material with a high-quality thickness of up to 150 mm.
- The cost is comparable to the value for money.
- Plasma cutting can easily handle curves, odd shapes, and intersecting cuts.
- The process was very quick and efficient.
- Water can be cut, resulting in a smaller HAZ. Reduces noise levels as well.
- Versatile and appropriate for a wide variety of conductive materials.
- The best method for cutting medium-thickness stainless steel and aluminium
- CNC plasma cutters with high precision and repeatability are available.
- When compared to flame cutting, the cutting kerf is smaller.