Plasma Cutting: Process, Strengths, and Weaknesses

What is Plasma Cutting

Plasma cutting is a fast and efficient metal-cutting process. It is the process of cutting metal materials to the desired shape by accelerating the plasma to a certain level.

Plasma is a fourth-state material composed of gases or ions ionized at high temperatures, which has good electrical conductivity and energy conductivity.

In the cutting process, the gas is first heated to a very high temperature to form a plasma through a process called plasma arc.

These plasmas with high energy are then focused on the metal workpiece, heating the metal workpiece locally to melt or even burn, thus serving the purpose of cutting. This is plasma cutting.

History of Plasma Cutting

Plasma cutting can be traced back as far as the 1950s when the industry began to seek a faster, more efficient method of cutting metal to replace traditional flame and mechanical cutting.

• The concept of plasma cutting was first introduced in the 1950s, during which time scientists and engineers began utilizing plasma to heat metals.
• In the 1960s, plasma-cutting technology was more mature and gradually began to be commercialized, and engineers developed plasma-cutting equipment that could be used in industrial production and began to be applied to industry on a large scale.
• In the 1980s, with the advent of computers, automated plasma cutting systems began to appear. These systems were able to achieve more precise cuts through computerized control, thus increasing factory productivity and product quality.
• Since the 1990s, plasma-cutting technology has developed rapidly, and many more advanced technologies and equipment have emerged, such as high-energy plasma-cutting technology, multi-axis control systems, laser-assisted plasma-cutting technology, etc. These are constantly promoting the development of this field.

Why Use Plasma Cutting

Plasma cutting has a wide range of applications and can be used to cut all conductive materials. The cutting speed is fast, the maximum cutting thickness can be up to 150mm, and the cutting mouth is smaller compared to other cutting methods, so the error of the workpiece cut by plasma is smaller, and the quality of the workpiece is higher. The following will start with some of the advantages of plasma cutting, and bring you a deeper understanding of it.

Cutting Speed:

Plasma cutting cuts faster than any other cutting method, and it can save you up to three-quarters of your time, helping you complete your project faster and more efficiently.

Because it does not require preheating like other cutting methods, you can start the cutting operation straight away. Moreover, plasma can provide high energy, which increases the cutting capacity.

Suitability:

Plasma cutting is widely used in many different industries precisely thanks to his adaptability. He can cut many different types of materials, such as metals, plastics, glass, and more. He can even cut different materials that are stacked on top of each other.

Cutting Quality:

Plasma cutting is synonymous with high precision and can cut a variety of complex shapes with high accuracy. Due to its fast cutting speed, the short time it stays when passing through the workpiece will reduce the heat transfer to the workpiece, thus avoiding the warping of the workpiece due to excessive heat. It keeps the workpiece basically consistent and reduces the scrap rate and the trouble of shaping at a later stage.

Piercing Speed:

The speed of piercing is also one of the highlights of plasma cutting. As many cutting applications require internal perforation, for example, some processes that cut with oxygen fuel have to be heated up to 100 degrees Celsius when they want to penetrate a 15mm sheet of metal, and this process takes at least 30 seconds, but plasma cutting doesn’t need to worry about this, it can start straight away.

Safety:

Since the gas used for plasma cutting is inert, it is much safer to use than cutting methods that rely on oxygen, and the same applies to the transportation of cylinders and the replacement of cylinders.

How Plasma Cutting Works?

Plasma still works on the simple principle of passing gases through narrow outlets, thereby creating an electric arc; these gases can be air, oxygen, argon, nitrogen, and so on. During this process, the temperature of the gas will be raised to the point where it can enter the fourth state of matter, a state that scientists call the plasma state.

We are already familiar with the other three states of matter: solid, liquid, and gas. When cutting, since the workpiece to be cut needs to be electrically conductive, our workpiece is part of the whole circuit so that the plasma arc can be moved to the workpiece, causing it to melt and thus cutting.

Plasma Cutting Process

Preparation:

• First, prepare the workpiece to be cut, the plasma cutter, and a comfortable working environment.
• Ensure that the workpiece to be cut is secured, that the cutting path is planned, and that there are no foreign objects blocking the cutting path.
• Check the equipment for any abnormalities and whether it can operate normally to ensure that there are no hidden safety hazards.
• Bring your safety equipment, such as protective eyewear, helmets, gloves, suits, earplugs, etc., to avoid accidents!

Setting Cutting Parameters:

• Depending on the type of material you want to cut, the thickness, the path length and the quality of the cut you expect to achieve, you can set the parameters of the plasma cutting machine, such as the type of gas to be used, the flow rate, the current, the voltage and so on.
• If the above parameters are not set properly, it will affect the plasma temperature, cutting speed, and stability, which will directly affect the cutting quality.

Start Cutting:

• Next, you can start the machine, but you need to always observe the quality of the cut, the speed of the cutter head and the operation of the machine in order to make timely adjustments.
• To ensure that the cut is of good quality and that the cutter head trajectory does not deviate from the preset one
• If problems occur during the cutting process, such as poor cut quality, poor melting and poor gas removal, it is necessary to promptly adjust the machine parameters to the head position and the speed of the cut.

Cleaning and Inspection:

• When cutting is complete, turn the machine off and clean the work area in a timely manner to remove any molten metal residue that may be generated
• Inspect workpieces to ensure that the desired quality can be achieved, sanding or trimming areas that may be defective

Applications of Plasma Cutting

Plasma cutting is widely used in many industries and manufacturing areas because of its high efficiency, precision, and universal applicability to a wide range of metal materials. Here are a few of its main application areas:

• Metal Processing: Plasma cutting is widely used in the metal processing industry for cutting, drilling, and contouring various metals such as steel, aluminum, and copper. It can be used to process automotive parts, aerospace parts and building structures.
• Metal Fabrication: In the fabrication sector, plasma cutting allows relatively large metals to be cut to the required dimensional size for downstream manufacturing, including the cutting of plates, tubes and profiles.
• Preparation for welding: in welding, the need for some of the workpiece to cut, to facilitate the smooth progress of the welding work, this time the plasma cutting plays its role, it can remove the edge, reduce burrs, is conducive to improving the quality of welding.
• Scrap Handling: Plasma cutting can also be used for scrap handling, cutting scrap metal materials into appropriate sizes so that it is easy to melt the scrap for reprocessing or recycling.

Materials for Plasma Cutting

Plasma cutting can cut virtually any conductive metal material, and the following are some commonly used materials:

• Carbon steel: common structural steel
• Stainless steel: materials with corrosion resistance
• Aluminum alloy: lightweight and strong metal material
• Copper and copper alloys: Copper and its alloys with good electrical and thermal conductivity can be cut better.
• Titanium alloy: excellent strength and corrosion resistance
• ALLOY STEEL: Steel that includes a variety of alloy compositions, usually with high strength and wear resistance.

Plasma Cutting Parts and Example

Plasma Cutting vs. Other Cutting Methods

Laser Cutting

• Principle: Laser cutting is achieved by using a high-energy laser beam to heat the material until it melts, vaporizes or evaporates, and then blowing the waste material away from the cutting position with an air stream.
• Advantage: Laser cutting has high precision, fast cutting speed, and is applicable to a wider range of materials, both metal and non-metal, and can cut many complex shapes.
• Disadvantages: the high cost of laser cutting, the requirements of the environment are more stringent, the thickness of the cut metal is limited, and the metal is more reflective to it.

Flame Cutting

• Principle: Flame cutting uses oxygen and fuel to generate a high-temperature flame that heats the metal until it burns or melts.
• Advantage: Flame cutting is low cost, can cut metal thicknesses, and does not use much electricity and is not limited by power supply.
• Disadvantage: It has slow cutting speed, low precision, and is not suitable for cutting small workpieces or non-metallic materials.

Waterjet Cutting

• Principle: Waterjet cutting is the cutting of workpieces with a high-pressure stream of water to which fine abrasives are added.
• Advantage: Waterjet cutting does not produce a heat affected zone and is very suitable for cutting materials with poor heat dissipation, such as plastics and rubber.
• Disadvantages: waterjet cutting is generally accurate, equipment and maintenance costs are high, and the results of cutting thicker metals are less than ideal.

Reach a Verdict:?

Compared with the above three processes, the advantage of plasma cutting is between laser cutting and flame cutting: its cutting speed and accuracy are better than flame cutting, but the cost is relatively high; compared with laser cutting, plasma cutting is less expensive and is not affected by the reflectivity of the metal.

Future of Plasma Cutting

Plasma cutting is sure to evolve in the future as an efficient and cost-effective cutting technology to meet changing needs. Here are some of my personal views on the future of plasma cutting:

• Improving cutting accuracy and speed: Future plasma cutting technology may further improve cutting speed and accuracy by improving the cutting head, optimizing parameters, and introducing advanced control algorithms and sensor technology to meet the demand for efficient and precise processing.
• Expanding the scope of application of materials: It can also expand the scope of application of the materials it cuts, including a variety of new metal alloys, composite materials and non-metallic materials.
• Intelligence and automation: the future can also become more intelligent and automated, the introduction of artificial intelligence, machine learning and automation control technology, intelligent, adaptive control and remote monitoring, can improve production efficiency.
• Environmental protection and energy efficiency: I hope that future plasma cutting technology will pay more attention to environmental protection and energy efficiency, optimize energy use, reduce waste generation, introduce environmentally friendly materials and process technology, and reduce the impact on the environment.

About EVERGREEN

At Evergreen, we leave no metalwork untapped. We have a multitude of metalworks to offer; ranging from laser cutting, plasma cutting, bending, nibbling, and punching to stamping and welding.

Putting the customer above all, as usual, Evergreen has introduced Metalworks in the most versatile thickness range. On the top, looks aren’t compromised and a fine finishing material is used. Evergreen deals in an extensive variety of welded parts and stamping parts.

Conclusion

All in all, plasma cutting is a cost-effective and efficient cutting technology that can save you as much money as possible while maintaining high cutting speeds and relatively high accuracy, helping to accelerate your company’s growth.

However, it should be noted that you need to choose the right cutting process according to your needs, for example, if you have high requirements for cutting accuracy, then laser cutting is the most suitable for you; or if you do not have high requirements for accuracy and speed, and you want to minimize the cost, then flame cutting is the most suitable for you.

In the future, with the development of technology and the addition of artificial intelligence and automation, plasma cutting will be greatly developed, and is expected to bring more efficient and precise cutting solutions for industrial production.

Things You Might Want To Know (FAQ)

What Are the Safety Equipment When Plasma Cutting?

Safety equipment during plasma cutting includes: protective clothing, face protection, respiratory protection, hearing protection, foot protection, ventilation, fire safety equipment, and first aid kits.

In fact, the most important thing is to train employees on safety and ensure that they are sufficiently aware of plasma cutting and are proficient in emergency procedures and the ability to respond to potential hazards.

Gas Used in the Process

The following gases are typically used in the plasma-cutting production process:

• Plasma gases: including nitrogen, oxygen and air
• Protective gases: Nitrogen and argon are usually used.
• Combustion gases: including flammable gases such as acetylene, propane, etc.
• cooling gas (i.e. gas that cools the atmosphere)

How thick can a plasma cutter cut?

The thickness of a plasma cut is determined by many factors, such as the type of cutter, the power of the cutter, the design of the cutting head, the type and pressure of the cutting gas, and so on.

Handheld plasma cutters are suitable for cutting thinner metals, and their cutting thickness usually ranges from 1.5 mm to 20 mm. CNC plasma cutting machines, on the other hand, cut thicknesses between 2 mm and 150 mm, depending on the power.