What Is the Difference Between a Laser Cutter and a Plasma Cutter?

Laser-Cutter-vs-Plasma-Cutter

For many projects that involve metal construction, you are going to need to be able to cut metal. Obviously, you cannot do this with a pair of scissors. Plasma cutters and laser cutters are two tools you can use to cut through metal.

What is the difference between a laser cutter and a plasma cutter? A laser cutter uses a laser beam to cut through metal, while a plasma cutter uses high-temperature gas to do so.

Since both can cut through metal, does it matter which one you use?  We are going to explain the differences between them as well as the advantages and disadvantages of each.  That way, you will know which one would be best for your purpose. 

Laser Cutter vs Plasma Cutter?

If you want to know the difference between a laser cutter and a plasma cutter, it is a good idea to first figure out what exactly each of these machines does. They both function to cut through metal. The main difference lies in the mechanism by which they operate.

laser-cutter-machine
Image credit: Hallmark Nameplate

What Is Laser Cutting?

Laser cutting was initially developed as a method of cutting holes in diamonds. It uses a high-power laser, controlled by a computer, to cut through the material. In addition to a laser, the tool requires compressed air, nitrogen, and oxygen.

The laser beam comes from a tube and is reflected into the laser head by several mirrors that are a part of the machine. Then, a lens located on the interior of the head will focus the beam onto the surface of the material that you want to cut or engrave.

When the laser beam is focused on the area of metal that you were trying to cut, it will produce a significant amount of heat. This heat will melt or vaporize the metal at the area of the incision, and an auxiliary gas blows away excess material from this area.

There are two main types of laser cutters, CO2 and fiber lasers. A CO2 laser will not be able to cut through any reflective surface, such as brass, copper, or aluminum. However, it will be able to cut through acrylics and wood. A fiber laser can work with any type of thin metal sheet.

The Parts of a Laser Cutter

A laser cutter is composed of the primary apparatus, as well as auxiliary equipment that is necessary for its operation. The primary apparatus is what is responsible for the focus and movement of the laser, as well as the electrical processes behind it. The auxiliary equipment contains the water chiller, air compressor, gas cylinder, gas storage tank, filter, discharging machine, and other critical components.

The mechanical part of the machine that allows for the movement of the laser is the laser cutter frame. This is what is mostly responsible for the precision of laser cutting. The laser generator is what produces the light, comparable to the engine of a car. These machines also contain lenses, which are instrumental in the refraction and aiming of the laser.

These cutters also have control systems, which control the movement of the machine and the output power of the laser. The quality of this machine will have a significant effect on the performance and precision of the machine.

Another part of these machines is a cutting head, which is a laser output device that contains a nozzle, a focus tracking system, and a focusing lens. This is what will move the head on the axes along the line of incision.

The operator will have to adjust the height of this component based on the material that is being cut, its thickness, and the method of cutting. The machine also has a motor, which is primarily responsible for the motion. The quality of the motor will have a significant impact on the efficiency of the device.

Other equipment that contributes to the way these cutters function includes a water chiller, which keeps the machine working correctly by neutralizing excess heat that it generates. There is also a dust extractor, which filters and treats the residue that is produced during the cutting process, and a slag discharge machine, which eliminates waste materials that are generated.

What Is Plasma Cutting?

Plasma cutting is the oldest form of cutting. It was developed as an alternative to simply using fire in the 1950s. A plasma cutter fires a superheated and electrically ionized gas through a nozzle towards the material you are trying to cut at an extremely high speed. This gas is referred to as plasma.

plasma-cutter-machine
Image credit: 911motorsports.net

While the gas is being aimed towards the material, an electrical arc forms and creates electrical conduction within the plasma, which generates heat. This heat allows the plasma to melt right through the material. The plasma in compressed gas will then blow away any molten metal that is present, which will ultimately yield a separated piece of metal.

Related article: You can read all about the key difference between Plasma cutter and Oxy-acetylene Torch cutter and when to use a torch cutter by clicking on this link.

Usually, nitrogen or oxygen are used as the working gas that makes up the plasma. This plasma will melt and evaporate the metal located at the incision site. In order to form the seam, it will use the momentum of the high-speed plasma flow to get rid of the molten metal in that area.

Plasma is often stated to be the fourth state of matter, along with solid, liquid, and gas. It can be created when additional energy is infused into a gas. This allows the gas molecules to collide with one another with a higher amount of force, moving much more quickly. This higher number of collisions caused the molecules to split apart into the atoms that form them. The atoms also relinquish their outer shell electrons and form ions. There are several free electrons moving around and shuttling between atoms. At this point, the gas is now plasma.

Related Article: Can Plasma Cutter Cut Aluminum? | A Complete Guide

The Parts of a Plasma Cutter

There are several parts of a plasma cutter that contribute to its operation. The external power supply uses both DC and AC voltage. It converts the AC line voltage from external circuits to DC voltage, which also regulates the output of the machine. The machine also consists of an arc starting console, which is part of what generates the AC voltage. This leads to the spark inside of the plasma that is needed for the creation of the plasma arc.

The part of the machine that most people will be focusing on during operation is the plasma torch. This is where the ionized gas will exit the machine in the form of plasma. It keeps all the consumable parts aligned, and it regulates their temperature even as the extremely hot plasma is being generated.

The air is released through the nozzle, and there is also the swirl ring on the interior. The swirl ring holds the electrode in place, and the electrode is what is responsible for the difference in charges that leads to the plasma arc.

In some cases, there is an additional shielding cap that will improve the quality of the final cut. Additionally, there are inner and outer retaining caps. These serve the purpose of holding the parts of the plasma torch together.

What Is the Difference Between These Machines?

The most obvious difference lies in what is used to cut metal. Plasma cutters use compressed gas to do this, while laser cutters use optical light and the heat that it generates.

Because of the way these machines operate, they are each suitable for a different subset of jobs. Neither type of machine is unequivocally superior to the other; instead, either one can be the better choice for any given metal cutting job.

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How Can You Decide Which Type of Cutter to Use?

If you are trying to decide between a laser cutter and a plasma cutter, you should think about the type of job you are trying to get done.

How Is a Plasma Cutter Useful?

Plasma cutting can be used to cut a variety of metallic materials, mostly different types of steel. It is relatively inexpensive, as well. The machine costs less than the laser cutter, and it also generally tends to need cheaper maintenance as time goes on.

Most of the time, a plasma cutter is used to cut metals of medium thickness. Plasma cutting is better for thicker materials in many cases. When the material is 50 millimeters thick or more, a laser cutter will not be able to do the job. A plasma cutter will be able to cut material that is 50 millimeters thick, although it will usually not be able to cut material that is 100 millimeters thick or more.

In addition, a plasma cutter can cut materials of medium thickness at a much higher speed than laser cutting can achieve. Even if the laser cutter is capable of cutting materials of this thickness, which would be under 25 millimeters, it will not do so as quickly as a plasma cutter.

Also, plasma cutters are convenient in that they are generally portable, while this is generally not the case for laser cutters.

How Is a Laser Cutter Useful?

Laser cutting is often the better choice if you are working with thinner materials, up to 25 millimeters in thickness. Also, the precision of the cut tends to be higher, with a narrower cutting seam on the finished product. There is also less deformation of the material and surface roughness. It is possible to use the cutting surface directly for welding without prior grinding when you are using a laser cutter, since it does not have the same amount of slag, or waste material, that a plasma cutter would produce.

When you are done with the laser cutting process, the cutting edge is not oblique, as it is expected to be with plasma cutting most of the time. This is because the laser has a precise focus, as well as high intensity and brightness. Generally, with plasma cutting, subsequent processing is necessary, whereas this is not the case with laser cutting.

Laser cutters are also more eco-friendly since they are quicker and use less energy than plasma cutters do. They also do not give off all the potentially toxic materials that plasma cutters do.

You can also use laser cutting with a broader range of materials, including ceramic, glass, wood, textiles, and other non-metal materials. Plasma cutting does not work on materials other than steel.

In addition, while laser cutters are capable of cutting, welding, and engraving, plasma cutters are generally limited to cutting. If you have a laser cutter, you can not only cut but create different designs using metal. You can even use a laser cutter for 3D printing, which is becoming increasingly popular.

What Are the Disadvantages of Laser Cutting?

At first glance, it might look like the laser cutter is usually the better choice. However, this is not the case. Cost is often a significant consideration for these projects, and a laser cutter will be more expensive both in terms of initial investment and maintenance requirements later.

If you are cutting a thin material, it will probably be more cost-effective to use a laser cutter. However, when you are cutting a thicker material, a laser is not the best choice. Because of the low efficiency, it makes more sense to use a laser cutter with thicker material when you need extremely high quality and an exact cut. The processing quality also varies based on the material that you are cutting.

Remember, also, that it is more difficult to find someone who can use a laser cutting machine since it requires a higher level of skill than a plasma cutting machine does.

What Are the Disadvantages of Plasma Cutting?

The plasma cutting process is quick, and the heat affected area is small as well. However, at the incision site, there is typically a tiny angle, between 0.5 and 1.5 degrees, where ideally the angle would be zero. The poor perpendicularity of this process makes it so that additional processing is often required even after the cutting is done. Also, even though the plasma cutting process is relatively quick, the laser cutting process is faster when the cutting material is thin.

Plasma cutting will also produce more cutting slag, or excess material. The slag will be at the bottom of the cutting surface, and you need to remove it by grinding. This will make for more work and also increased labor costs. Also, the slag means that there is more wasted material. The incision is bigger, and more material is lost than would be lost with the laser cutting process.

Learn More About the limitations of Arc Plasma Machining – Here, you can find an article from our website about: What are the Advantages and Limitations of Plasma Arc Machining?

Unlike the laser cutter, the plasma cutter will do damage to the metal in most cases. This damage will be particularly pronounced if the nozzle and torch of the machine are defective. The amount of metal destroyed will also be more extensive, since the cutting slot is larger with a plasma cutting machine.

The plasma cutting process will also consume more of the cutting nozzle over time, which can be expensive. Additionally, the plasma cutting process will generate harmful gases, radiation, and arc light. Because of this, it is necessary to wear protective gear when you are using a plasma cutter. However, underwater plasma cutting has been shown to work without this problem.

Plasma cutters produce a large amount of dust as well. They are also noisier than the laser cutters tend to be.

Final Thoughts

When you are taking on a heavy-duty project, such as cutting metal, you want to make sure that you select the right machine for the job. If you select the wrong machine, you could end up with poor results. In some cases, you might even have to start all over, which will end up costing you precious time and money. This is why it is worth your effort to learn the differences between a plasma cutter and a laser cutter so that you know which one to pick next time you have to cut metal.

There are some jobs that you can pick either machine to do. However, in most cases, one will work at least slightly better than the other. This is why it’s a good idea to do your research and figure out which one to choose, based on the type of metal you are trying to cut, its thickness, the money you have to spend on the project, and the conditions you are able to provide for the labor.

If you make the right choice, you will have a higher chance of ending up with a high-quality product. Remember, neither of these options is superior to the other, just more suitable in different circumstances. You can work with very high-quality plasma cutters and very high-quality laser cutters. After you choose the type of machine you are going to use, it will be essential to make sure that you pick a high-quality machine to do the job for you.

Sources:

ACRA Machinery

MachineMfg

Thomasnet.com

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David Harper

David is the Co-Founder and Senior Editor at weldingtroop.com. David's an experienced fitter and tuner/welder who's passionate about helping others develop in life through new skills and opportunities.

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