Most of the time we don’t think about how the construction tools work. They do their job and it seems more than enough. However, knowing the operation principle of various equipment can help you learn how to get the job done quicker and pay more attention to the safety.
Plasma cutters might seem like something from a sci-fi movie where futuristic tools are doing something close to magic. However, this equipment is actually rather old…some might even say, middle aged.
What is Plasma?
In order to get a better understand of how a plasma cutter works; let’s take a look at what plasma is.
There are four states of matte: solid, liquid, gas, and plasma. Plasma is the closest to gas than all other states. How do you change one state of the matter into the next? You heat it up. By heating up the solid matter, you turn it into liquid. Heating the liquid will turn it into gas. Heating up the gas will eventually turn it into plasma.
Plasma is a complicated state of matter. Heating forces the electrons to separate from the nucleus. Once they are released from the atom, electrons start moving very quickly. Since they are negatively charged, the electrons leave positively charged ions behind them. The collision of the fast electrons and ions leads to the release of great amounts of energy. This energy is what allows the plasma to cut through the metal.
Interesting note #1: Plasma is the most common state of matter in our universe.
Interesting note #2: The biggest piece of plasma we know is the sun.
How Does a Plasma Cutter Work?
Now that you know what plasma is, it’s easy to understand how plasma cutters work.
The goal of the plasma cutter is to turn gas into plasma in order to use it for cutting.
Plasma cutters send pressurized gas (it can be nitrogen, argon, oxygen, etc.) through a small channel. In the middle of the channel, there is a negatively charged electrode. Once the plasma cutter is plugged in, it sends the power to the electrode. Then the plasma cutter touches the metal and this connection results in a circuit. A spark is generated. Meanwhile, the gas passes through the channel and meets the spark, which heats it up until the gas turns into plasma. Voila!
Two Types Of Plasma Cutters
In the modern world, there are two types of plasma cutters. The choice of a plasma cutter depends on the volume of work that needs to be performed and the skills of an operator.
Manual Plasma Cutters
Manual plasma cutters are the most popular cutters for individual use. Hand-held plasma torches are portable, maneuverable and versatile. These cutters use shop air as a gas and can work with several incoming voltages. They are good for using on thin metal, so they are popular at metal service centers and can be used for construction work, vehicle repair, and artwork. Their main use is trimming the excess material from various metal parts.
When choosing a manual plasma cutter, you have to consider the thickness of the material you are planning to cut and the cutting speed you can handle. Fast cutting speed = low precision. Manual devices often can be configured to suit the operator’s skill level. However, most plasma cutters have a high learning curve. The risk of an electric shock when using a manual cutter is rather high. That’s why safety precautions are vital.
Automatic (CNC) Plasma Cutters
CNC (computer numerically controlled) plasma cutters are easier to use since the computer controls the way a head moves. This allows the cutter to make precise cuts and eliminates the human error during the cutting process. An automatic cutter increases the output and decreases the time required to get the job done. Automatic cutters are large machines that require a substantial amount of space. They are usually used in large service shops or factories.
While there is no need to teach operators to wield the cutter, you need to teach them how to work with the software. Most of the time, the learning curve of a CNC plasma cutter is much smaller than of a manual cutter. Automatic cutters are more expensive and require an extra power supply, which is not always available. Meanwhile, they offer you a chance to improve the cutting quality and quantity as well as the complexity of the work.
While there isn’t anything complicated about a plasma cutter, it’s still one of the most interesting tools developed in the 20th century. By taking what they nature gave us, we managed to create a powerful machine that didn’t just simplify the U.S. aircraft manufacturing business, it perfected the approach to construction all over the world.
You can check out both types in our full Plasma Cutter reviews page
A little history
The first plasma cutters appeared in the middle of the 20th century during World War II, when the U.S. engineers needed a more sophisticated way to join aircraft spare parts. They used inert gasses fed through an electric arc to completely replace the standard welding process.
After WWII was over scientists continued to research the innovative welding way and found out that they could improve the process. They restricted the inert gas flow opening to the nozzle, which altered the electric gas arc particles. This substantially boosted the speed and the temperature of the gas. It turned out that the plasma technology didn’t just help join the metal together, it could cut it up with ease.
Further research was done with the type of gas, gas flow rate, size of nozzle, voltage current and etc. Many tests were run to improve the plasma torch or plasma cutter of the 20th century. However, there were downsides of plasma cutting, such as loud noise, toxic gas, certain levels of UV radiation, and short nozzle life.
In the 1970’s European scientists came up with an underwater plasma cutting. This eliminated many side effects, such as toxic smoke, UV radiation, and noise, but significantly affected the precision since the operators couldn’t precisely see and control what they were doing.
In the 1980’s low amp plasma cutter appeared on the market. This breakthrough technology used pure oxygen as a plasma gas. After an underwater muffler and various oxygen injection technologies were developed, the popularity of underwater plasma cutting went through the roof.
In the 1990’s, plasma cutters faced a worthy competitor. When a laser appeared on the market, it immediately became extremely popular due to the precision it offered. Plasma cutter manufacturers quickly came up with a few innovations in order not to lose their position on the market.
Over the past 20 years many new technologies have been developed to maintain the popularity of a plasma cutte. Since these cutters are not as expensive as the lasers, they are still widely used. Computer-controlled cutters and portable devices became a choice of many companies and homeowners.