You want to buy a plasma cutter, but you don't know how they work.
A plasma cutter is an excellent tool for cutting metal and other materials. They are used in many industries such as construction, manufacturing, and automotive repair.
99% of all matter in the universe is plasma. This includes stars and other things.
Plasma cutting is a thermal cutting method that uses ionized gas to cut metal. It works by sending a thermal arc through ionized gas. The thermal arc passes through the ionized gas. Fuel is squeezed through the hole in a carburetor at high speed and mixes with air passing through it. The gas cuts through the metal and makes it into pieces.
This article will explain the basics of how a plasma cutter works so that you can make an educated decision about which one is right for your needs.
This article will help you understand what makes a good plasma cutter by explaining the different parts of it and its functions.
Let's dig right into it.
# Table of Contents
What is Plasma?
Plasma is a gas made up of free electrons and positively charged ions. It is the fourth state of matter, after solid, liquid, and gas. If you are wondering just what that means for you? Plasma is often found in stars or any other place with extreme heat and pressure. What does this have to do with your day-to-day life? Let's explore the different ways plasma can be used in modern welding society.
What is the science behind a plasma cutter?
A plasma cutter is a cutting tool, primarily used to cut metal, rock, and other hard materials.
Plasma cutters work by directing gas through an orifice that sends an electric arc through the gas. The heat of the gas causes it to turn into plasma, which is where electrons collide and release energy. This makes for very high heat and thus cutting power.
They work by projecting a stream of electrically charged gas at a workpiece while subjecting it to high pressure which then shears the surface material from the desired object without heating it (since they typically reach temperatures on the order of 30,000 degrees F).
This means that it can be used faster than conventional methods for cutting metal such as using an oxyacetylene torch or mechanical saws. These characteristics make them quite popular in engineering projects such as shipbuilding where you need to cut large pieces quickly and efficiently.
What do you need to run a plasma cutter?
In order to run a plasma cutter, you will need an air compressor and a Power source as well as The Arc Starting Console, Gas composition, Cooling system, and Plasma torch. Now I will give a brief description of each one.
01. Air Compressor:
It is most likely that the air compressor will be embedded into the wall or floor, but if it is not then it can be easily mounted on a stand. It should have a large enough tank to keep up with the high demand of your arc starting console (60 mins-70mins) and a pressure gauge to monitor the air supply.
02. Power supply:
The plasma power supply is a device that converts AC voltage into DC voltage (200V to 400VDC). This is responsible for keeping the plasma going when you are cutting things. It also controls how much current goes through, depending on what material you are cutting and how thick it is.
03. Arc Starting Console:
The ASC circuit makes a lot of voltage. This voltage is inside of the arc we use to make plasma.
In this case, the AC frequency is about 2 MHz, so each half-cycle of AC takes about one millisecond. The voltage is about 5,000 VAC.
04. Plasma torch:
A plasma torch is a tool that helps make good cuts. It does this by holding the consumables together and making sure they're cooled so you can see the cut.
The main parts it has are the electrode, swirl ring, and nozzle. The electrode is rounded and smooth to focus the plasma.
The swirl ring creates a current in the air and prevents soot buildup on the nozzle tip. The nozzle puts out plasma at different angles to cut at different depths, or it can also be used as a flame for welding.
Then there's a cap that you put over all of these parts to hold them in place.
05. Gas composition:
In a conventional system, the plasma is created with an electrode made of tungsten. With this kind of system, the plasma is not reactive.
This type of plasma can be made using argon or argon-H2 or nitrogen. But another way to make a reactive (reacts) plasma is with copper and hafnium on an oxidizing gas such as air or oxygen.
You need to set the gas flow to the right level. You need to be careful when you set this up so that you don't have a problem.
If it is too low, then the arc will break down and make two arcs in series. The first one will be going from your electrode to your nozzle, and the second one will be going from your nozzle to whatever metal piece you are trying to melt with it.
This might not work very well because the metal might get hot enough but won't melt. If you set the gas flow too high, then it will make a really big arc that will carbonize/burn the electrode.
It would also probably make your workpiece hot but not melt it.
06. Cooling system:
When dust is heavy in the air, and there are metal shavings on the ground, it can be hard to keep your machine from getting dirty.
When you have Wind Tunnel Technology, then the cooling air won't blow over your machine. That will stop dust from settling on important parts of your machine.
Fan-On-Demand means that when you use this technology with a plasma cutter, and then only when it is needed will the fan turn on to cool down your machine.
Regarding air supply, most people who use a hand-held plasma cutter recommend using ordinary air as the cutting gas because it costs less than bottled nitrogen gas for mobile applications.
Some people believe that if you are cutting stainless steel and want to cut more slowly or not at all, then nitrogen is slightly better than air, as it is drier and causes less oxidation.
How does a plasma cutter work step by step?
A plasma cutter is a tool that cuts metal. It works by sending an electric arc through gas. The gas can be air, nitrogen, or argon. When it gets hot enough, it changes to the 4th state of matter called plasma.
This is the same as when you use duct tape and heat it up with a lighter and then you see the flame on it.
When cutting any section of metal, electrical conductivity from this plasma makes things easier to cut and lets in electricity from outside sources like power outlets.
This goes into where there are wires in your house and cuts them easily so you don't have to do much work on this one which saves time for us all!
Fuel is restricted as it passes through the opening (nozzle); this restriction causes the fuel to move at a high speed, like air passing through a venturi.
This gas cuts through the molten metal and is also directed around the perimeter of the cutting area so no sparks are emitted, making it safer for both cutters and spectators.
Most of today's plasma cutting systems can be placed into two categories. One is called conventional (Handheld Operation) and the other is called precision.
01. Handheld Operation
A handheld plasma system typically uses air as the gas. The shape of the plasma is defined by a tube that has an opening. The size of this opening determines how big and strong the electrical charge is, which determines the size and strength of its arc. And how much electricity does it use? It depends on how big you make the opening in the tube. Arc amperage ranges from 12-20K amps per square inch, and this type of plasma is used for handheld systems and also in some mechanized applications where part tolerance isn't very important.
In a handheld plasma cutter, the electrode and nozzle are touching when it is off. The trigger makes a DC current flow between them. Once enough pressure builds up, these two parts are forced apart because of an electrical spark. Then the DC current switches from being on the electrode to being on the nozzle to being in between them. This continues until you release the trigger.
The first problem is that the electricity will go through dust and dirt on the electrode. This might cause some sparks, which will not hurt your system but it might. The other problem is that there is a path between the electrode and nozzle when you squeeze your trigger. Any dust or dirt could short out your system if they are on either of these things.
02. Precision plasma operation
Precision plasma systems are designed to offer the sharpest, highest-quality cuts. These systems are more complex and include pieces to constrict the arc. The current density is 40-50,000 amps per square inch. Multiple gases such as oxygen, high purity air, nitrogen, and a mixture of hydrogen/argon/nitrogen are used for better results on many conductive materials.
In a precision plasma torch, there is an electrode and nozzle. They are separated by a ring with small holes in it. When the machine starts, it creates 400 volts of DC power and sends gas through the hose to the torch.
The nozzle is temporarily connected to the power supply through a pilot arc circuit, which connects things to make electricity flow from one part of the machine to another.
This makes energy come out of the middle part of that circuit into an electric arc that goes between them and then becomes very hot when it's done like a fire but stronger because it can't go out because it's inside something metal so there's no oxygen for it to burn up.
Next, there will be an Arc Starting Console that creates high-frequency sparks so that your plasma gas becomes electrically conductive.
Once this happens, current can flow from your electrode to your nozzle while pilot arcs of plasma are created. Then finally after this happens, high frequencies turn off and pilot arc circuits are opened.
After that, the power supply raises its DC current to your selected cutting amperage and replaces your pre-flow gas with optimized plasma gas for whatever you are trying to cut. Sometimes a secondary shielding gas is also used that flows outside of the nozzle through a shield cap so that it can constrict your plasma arc even further, resulting in a cleaner cut with very low bevel angles and smaller kerf.
What are the three types of metals that can be cut on the plasma cutter?
There is a multitude of materials that can be used on a plasma cutter but there are three basic categories:
- Steel
- Clad metal plates
- Aluminum.
It’s important to assemble your tools before you start cutting so that you can avoid wasting time. But not all plasma cutters can cut all three types of materials, and that’s why it is important to know what these factors are when you want to use a plasma cutter so that you can decide which one will be used for the desired material.
Plasma Cutter, Quality Cut Process Variant
Plasma cutting is a similar process to oxy-fuel cutting. However, with plasma cutting, the most melting happens at the top of the metal.
This makes it have a rounded edge or beveled edge. Sometimes this bad edge can happen if there isn't enough constriction on the arc.
To make sure there is good constriction and good heating throughout the cut, different torches are used that adjust how constricted and hot it needs to be for different lengths of metal or what type of metal you are using.
The process variants have been designed to help make the cuts better, quieter, and faster.
01. Dual gas
The process is like the regular system but there's another shield around the nozzle. This new shield helps with a few things: it makes the arc smaller and blows away metal that might be sticking to it.
You use different gases depending on what you are cutting, but normally argon, argon-H2, or nitrogen is used. Steel should have air, oxygen, nitrogen; stainless steel should have nitrogen, argon-H2, CO2; aluminum should have argon-H2, nitrogen, or CO2.
Plasma cutters have a few advantages over regular plasma cutters. First, there is less risk of getting the metal you are cutting to 'double arc', which could catch fire and start a fire. Second, these cutters can cut faster than traditional plasma machines, and third, they can create edges that are not as rounded.
02. Water injection
You need a lot of water to make this happen. The water is injected into the plasma and makes it hotter. The gas is usually nitrogen, but not always. The gas is ionized, and the process causes the plasma to flow along the rope-like strands of magnetic energy.
The advantages of plasma cutting are: it can make a better cut and it is faster. There is less risk of 'double arcing' and the nozzles last longer.
03. Water shroud
The water shroud helps to create a shield of cool water around the workpiece. The cool water helps to keep the surface temperature of the workpiece down. If you submerge your workpiece into the water, it should be submerged about 50-75mm below the surface. This way, it is not too close to the heat of the burner and it should help to keep things moving a bit slower so that you have more time before you need to remove your workpiece.
Water helps make the plasma cleaner because it is able to remove some of the fumes that are created by the machine. This helps keep your fume levels down, which prevents various illnesses. The water also dampens the noise the machine makes. This makes it quieter for those around.
In a typical example, noise is 115 decibels for conventional plasma at high currents. This can be reduced to about 96dB with a water shroud. The underwater noise may cut down to 52-85 dB.
When you cut, the water does not make it easier to cut well. Cutting speed and cutting edge are not improved.
04. Air plasma
In an air plasma torch, people use air instead of expensive gases. To do this, they need a special electrode that is made of hafnium or zirconium and mounted in a copper holder. The air can also be used to cool the torch after it has been heated to create the plasma. The advantage of an air plasma torch is that it uses less money than other torches because you don't have to use expensive gases for it.
The only thing that needs to be replaced is the electrodes. But there is a difference in the cost of tungsten and hafnium.
05. High tolerance plasma
In order to improve the quality of your cuts and compete with laser cutting, you can use an HTPAC system. This is a plasma machine that does very narrow cuts.
The focus of the plasma is affected by using a swirl of oxygen when the plasma enters and injecting gas downstream.
Some systems have a magnetic field that is separate from the arc. This helps make the plasma stable by keeping everything in place and rotating.
HTPAC is a way to cut metal. HTPAC machines can only cut 6mm thick metal. They don't cut as fast as plasma or laser cutting machines, but they're still good.
The HTPAC system has advantages. The cut is better than a plasma arc cut but not as good as a laser beam cut. The width of the kerf (the space between cuts) is narrow and there is less distortion in the wood because it doesn't get very hot.
What are the Plasma Cutter Pilot Arc Start Methods?
Plasma cutters use different ways to start the arc. Some cutters start the arc by touching the torch to what you want to cut.
Others use high voltage and high-frequency circuits. This method has some disadvantages. It can be dangerous, difficult to fix, and you need to pay more attention to it.
Plasma cutters will start a pilot arc in other ways when they are close to electronics like CNC hardware or computers.
The cathode and anode are touching. The cathode is the nozzle, and the anode is a metal rod. When gas flows through it, the nozzle gets pushed forward.
According to the Starting methods, the two most common types of Plasma cutters on the market are:
- Inverter plasma cutters
- CNC Plasma Cutter
01. Inverter Plasma Cutter
Inverter plasma cutters or Analog plasma cutters require more than 2 kilowatts. They use a heavy mains-frequency transformer. Inverters in plasma cutters convert the mains supply to a DC current and feed it into an inverter that uses a high-frequency alternating current at 10 kHz to 200 kHz. Switching frequencies can be adjusted to help decrease the size of transformers.
The transistors used to be MOSFETs, but are now IGBTs. When one transistor activates before the others have a chance, this can cause problems for all the other MOSFETs. IGBTs are not as likely to have this problem because they don't work together as often and they take more power when they do.
An off-line converter has two transistors. This kind of topology is used in many different places, even in plasma cutters. Although inverter cutters are lighter and more powerful, there are limitations in how you can use these from a generator.
However, newer models can work on a generator. Older models needed the power to be "corrected" before they could work.
02. CNC Plasma Cutter
Some places make the plasma cutter part of the cutting table, and some have it separate. If there is a CNC table, then you can control it with a computer. It will cut things in a very clean way.
Plasma cutting is for thick materials that are hard to cut without problems. You need special equipment to do this well. But if you want to make small holes in thin metal, lasers are better at this because they can do it really well and faster than plasma cutters can too.
The CNC plasma cutter helps in the HVAC industry. It cuts the patterns for ducts and it can make many of them at once. This saves time, which is important when making things like HVAC systems.
Moreover, CNC plasma cutters are capable of making several different types of signage including both commercial and residential, wall art, address signs.
In recent years, new machines have been invented. The old machines were horizontal and made long cuts, but now there are vertical machines. They are smaller and make faster cuts. You should use these new mini-machines because they have 8 times more power than the old ones.
Conclusion
It's been a pleasure to walk you through the process of how plasma cutting works. I hope that this article has answered any questions you may have had and was able to help your understanding of these machines. Now, it is time for me to conclude my blog post by asking one last question - what do you think? Is plasma cutting something that can benefit your business? If so, we are ready and waiting with our team of experts who specialize in custom welding solutions tailored just for you.
FAQ
What kind of gas do you use with a plasma cutter?
The most commonly used gas for cutting metal is compressed air. It can be used on gauge thicknesses to 1 inch. It leaves an oxidized cut surface on the metal. It can also be used for plasma gouging on carbon steel and stainless steel. The cutting action is very similar to oxy-acetylene, except that it does not have the same heat intensity capability.
Do I need gas for the plasma cutter?
Gas is needed to make a plasma cutter work. You can use different gases depending on what you want to cut and how fast you want it to cut. Oxygen has become the standard gas because it cuts steel the fastest of any of them so far.
Do you need oxygen for a plasma cutter?
Oxygen is the best gas to use for cutting mild steel. It gives a cleaner cut and a faster cut than any other plasma gas. You should not use oxygen to cut aluminum or stainless because it will not work well.
Why is my plasma cutter not working?
The air in the compressor is too low and the pressure valve is not high enough. There are many reasons that can cause this. If there is oil pollution, then it will stop working and you need to fix it as soon as possible because the oil will make the machine stop working if there is too much. If it's stopped working, you might need to maintain it.
Why is my plasma cutter sputtering?
One common problem that can happen with plasma nozzles is when the hole, in the end, becomes blocked. This can happen for a number of reasons, but often it is because of something like molten metal getting into the hole and then cooling to become part of the nozzle. If this happens, then it will change how hot and fast the plasma shoots out, which might make parts start wearing away on your nozzle.
Do I need gas for the plasma cutter?
Gas is needed to make a plasma cutter work. You can use different gases depending on what you want to cut and how fast you want it to cut. Oxygen has become the standard gas because it cuts steel the fastest of any of them so far.
Will a plasma cutter cut through rust?
Plasma can cut through any metal that is electrically conductive. This includes stainless steel, mild steel, aluminum, and more. Plasma does not need to be heated up before you use it because it's hot enough already! It also cuts dirty or even rusted metal very well-- even if the paint is still on.
Can you use a plasma cutter to cut bolts?
Plasma cutters can be used to cut things like metal. They are good for cutting rusty nuts and bolts too. You can use them to weld or melt metal, but it is fast. Make sure you have the right air pressure and everything will be OK.
How thick can a plasma cutter cut?
A plasma cutter is used to cut metal. You need air to make it work. It can cut a metal that is 01 inches thick. It takes a little while to cut. You can only use it for metal.
Do plasma cutters only work on metal?
Yes, plasma cutters only work on metal. Plasma cutting is only used on a few types of metal. This process can be used for mild steel, stainless steel, and aluminum. But lots of other metals are conductive too. They include copper, brass, titanium, Monel, Inconel, cast iron, etc.
Last Updated on November 2, 2021 by weldinghubs