Plasma cutting is a metal processing process in which a metal material is melted using an ionized gas heated to 20,000°C or higher. This high-pressure jet of gas melts the material and removes it from the cut.
This is how plasma cutting works. In order to know the mechanism of plasma cutting in detail, it is necessary to know what plasma is.
What is plasma?
Plasma is the fourth state of material after solid, liquid, and gas. A solid body has particles firmly stuck together and cannot change their position. In the liquid, the particles can overlap each other. However, in gases, particles are in a free state, and although it is easy to move from one place to another, the particles in them are not ionized.
Plasma is a special state in which gas particles are charged. Depending on its valency, it may be positively charged or negatively charged. Valency is the term used to describe the electronic arrangement of elements in an atomic state. For your understanding, plasma is actually current in the form of gases.
Can we create plasma?
Plasma does not occur naturally but occurs at more than 20,000°C. It is not present at all at temperatures below 20,000 C, and it changes into a normal gas. Therefore, it occurs only in the sun, where the temperature is too high. We can only create this by artificially giving this condition. Therefore, the plasma used in the plasma cutter is also artificially produced.
How is plasma created in a plasma cutting machine?
Plasma is generated by heating all gases to be charged and become excited. Everything, whether solid or liquid or gas, is made of atoms of elements. When heating a solid, it begins to melt at the melting point, changes into a liquid, and begins to flow. When the liquid is further heated, it evaporates to generate vapor, which is then converted into a gas. Molecules and atoms in a gas are excited by heat, and the repulsion between molecules and atoms increases, making it impossible for them to live together, and they change into a gas.
But what happens when invisible gases are heated? The answer is that when the gas is heated up to 20,000°C, the atoms of the gas molecules begin to lose electrons. Electrons are part of atoms. When these atoms lose electrons, gas atoms are charged and lose electrons. In this state, the gas enters a plasma state.
Thus, plasma is generated in the welding machine by heat generated by an electric arc. In the welding machine, the gas molecule attains a temperature of 20,000 degrees to lose electrons. We only use cathodes or electrodes that inject electrons into gas molecules and charge them. This is a method for generating plasma in a plasma cutting machine.
Plasma Cutter
The plasma cutter utilizes charged gas molecules generated from a cathode electrode and electric arc heat. The charged gas, also known as plasma, is used to melt or cut the metal that conducts electricity. High-concentration, high-pressure plasma (ionized gas) melts, cuts, and dissolves the metal through which electricity passes.
Appearance of Plasma Cutter
The plasma cutter resembles a torch from which plasma is ejected at high pressure and concentrated on the target material. A plasma cutter is similar to a torch cutter, but works differently. Plasma cutters are designed to cut materials very quickly.
How does a plasma cutter work?
The plasma cutter consists of electrodes and inert gases, or other types of gases that are converted into a plasma state when heated by high temperatures achieved during electric sparks.
There are two electrodes; one is the cathode, and the other is the anode. The cathode is located in the torch of the plasma cutter, and the other electrode is connected to the metal to complete the electric circuit that generates sparks. When the cathode approaches the anode, the anode is connected to the conductive metal that needs to be cut.
The gas also comes here at the time of the electric spark, heated by the electric spark and the charge of the cathode. The gas is heated into plasma gas. This plasma gas is capable of melting and cutting metal of considerable thickness.
Two Types of Plasma cutter
The two main types of plasma cutters are:
CNC plasma Cutting
This type of plasma cutting is automated using robots, and is more advanced than other types of plasma cutting because the computer that takes in the input and software in the machine understands the input and starts work. Since it is automated and controlled by a computer, software necessary for normal processing is also required. CNC uses software called CNS. CNC stands for Computer Numericla Control.
Plasma cutter using CNC is very fast and is currently the most widely used. It also protects workers from harmful radiation. In addition, the work is automated.
Handheld Plasma Cutting
This is not automated. It is used on small scale for small projects. You can hold the plasma cutter in your hand and work for long time. The plama is ejected out of its laser gun which cuts the metal apart.
How plasma cutting works?
Plasma cutting works only on metals that conduct electricity. If these metals do not conduct electricity, plasma and ionized gas cannot dissolve or cut them. The reason is simple: the charge moves through the conductor that passes electricity. Even if an electric charge from the plasma gas collides with a metal through which electricity does not pass, the metal is not affected at all.
Uses of the plasma cutter
Plasma cutters are used to melt conductive metals such as iron. Plasma cutting machines are used to melt conductive metals such as iron, copper, and gold. Plasma cutting can cut thick metal, unlike other cutting machines like laser cutting.
Type of materials cutted by plasma cutter
The biggest feature of plasma cutters is that they can cut any kind of material regardless of thickness. It can also cut inch-thick metal. However, the metal must conduct electricity well. Therefore, it can only be used with metals that pass electricity.
You can cut the following materials with it:
- Aluminum
- Iron
- Carbon steel
- Stainless steel
How much thickness of these metals may be but it cna cut them more better than the laser cutitng as its effect is very deep and the high energy from the plasma melts and cuts the metals either of high melting point.
What is better, a plasma cutter or a laser cutter?
If you want to cut the thin metals, then the laser cutter is good, but if you want to cut the high-thickness metal, the plasma cutter is the better option.
What is the best type of plasma cutter?
For your small projects, working with a handheld plasm cutter is good as its price is low, and you can work very well using this.