Waterjet and plasma are two of the most commonly used methods for cutting metal. However, deciding which method is best suited for your project can be confusing, leading to the question – which one should you opt for?

Well, it’s not really that straightforward. Although both technologies serve the same purpose, there is a significant difference in their functionality, the materials they can work with, their cost-effectiveness, safety features, and more.

In this article, we’ll compare waterjet vs plasma cutting, explore the pros and cons of each approach, and understand the most appropriate applications for these technologies.

So, let’s dive in!

Plasma Cutting Vs Waterjet Cutting: Overview

If you are in the metal fabrication field, you must have heard of waterjet and plasma cutting technologies. These two methods are distinct from each other, work with different products and cater to different applications.

But what separates them? In this section, we will explore the differences between these techniques, including their different types and the industries or applications where they are widely used.

What is Plasma Cutting?

Plasma cutting was invented by Robert Gage in the mid-1950s, and underwent several improvements over the following decades, particularly in the 1970s and 80s. By the 1980s, plasma cutting had already become a highly productive process for metal fabrication. 

During the late 1980s and early 1990s, plasma cutting underwent a major revolution with the introduction of CNC technology that expanded its capabilities. The 90s were memorable for plasma cutting, with major breakthroughs that significantly improved its reliability.

The operation of a plasma cutter involves ionizing gas with an electric arc, raising its temperature to extreme levels (above 20,000°C), and converting it into plasma. This extremely hot and electrically conductive plasma is used to melt and cut metals.

Different Types of Plasma Cutting

There are different types of plasma cutting systems used in the industry, but they can all be divided into two categories: automatic plasma cutters and manual plasma cutters.

Manual Plasma Cutters:

These handheld plasma cutters are used for light jobs in garages or homes. They come in two types: conventional and precision units. Conventional cutters use shop air, while precision cutters use multiple gases. They are more common but less precise.

Automatic Plasma Cutters:

Automatic plasma cutters are big CNC-controlled units designed for handling large-scale work. They come in various configurations, including 2-axis and 3-axis with a control head typically mounted to a table. They can cut more precise and complex shapes.

Where is Plasma Cutting Used?

Plasma cutting is a commonly used metal fabrication method that works equally well in both large-scale industrial settings and small hobby shops. Its ability to cut conductive metals such as steel, copper, and aluminum makes it highly effective.

Plasma cutting is often used in a variety of industrial applications including fabrication shops, automotive, construction, and other operations that require precision cutting of electrically conductive materials.

O que é o corte por jato de água?

It was in the 1850s when the technique of using high-pressure water to excavate the material was first used in coal mines. The paper industry later adopted it in the 1930s as an industrial device for cutting large quantities of paper sheets. 

Although it took several decades for waterjet technology to become commercially available, the Bendix Corporation introduced the first commercial water jet machine in the 1970s and further innovations continued in the years to come.

Waterjet cutting is based on a simple principle similar to that of a garden hose, but highly controlled and under much higher pressure. Water is pressurized up to 90,000 psi, and then forced through a tiny nozzle, enabling it to cut through almost any material.

Diferentes tipos de corte por jato de água

Waterjet cutting process can be divided into two main types: pure waterjet cutting and abrasive waterjet cutting. Below is a brief description of both.

Pure Waterjet Cutting:

Pure waterjet cutting (water-only cutting) refers to the process that involves using only water as the cutting force without adding any abrasives. It is suitable for working with soft materials, such as wood or rubber.

Corte por jato de água abrasivo:

Abrasive waterjet cutting is slightly different from pure waterjet cutting. In this process, a mixture of water and an abrasive compound such as garnet are used to cut hard materials such as aluminum or steel.

Onde é utilizado o corte por jato de água?

Waterjet is a versatile material-cutting method that can be used to cut various materials, unlike plasma cutting as mentioned earlier which can only deal with naturally conductive materials.

This makes it a great choice for many industries, including aerospace, automotive, electronics, food, medical, and any other operation that demands high accuracy and zero margin for error.

Plasma Cutting Vs Waterjet Cutting: How Are They Different?

Waterjet and plasma cutting differ not only in their working methods but also in many other aspects that determine their suitability for different applications. These include the working process, material compatibility, material thickness, and speed as well as the accuracy they provide.

For a brief comparison, please refer to the table below.

Processo de trabalho

Plasma and waterjet cutting are intended to cut materials, yet their behind-the-scenes operations involve different mechanisms that differ significantly. Below is a step-by-step breakdown of each method’s procedure for cutting material from start to finish.

Working of Plasma Cutter

Step 1: Supply of Gas and Electricity

Plasma cutting requires a power source and a gas supply (compressed air or inert gases such as nitrogen or argon), which is forced through a small nozzle at high speed.

Step 2: Completing the Circuit

An external electrical charge is applied to establish an electrical circuit. It create an electric arc within the gas, between the gas nozzle (electrode) and the workpiece.

Step 3: Formation of Plasma

The electric arc produces intense heat, causing the gas to ionize and reach extremely high temperatures (over 20,000 degrees Celsius) that transform it into a plasma.

Step 4: The Cutting Process

The superheated plasma is directed through the nozzle to the workpiece. Electrically charged particles transfer their energy to the workpiece, cutting it in the process.

Funcionamento da máquina de corte por jato de água

Step 1: Water Pressure

The water jet process starts with pump pressurizing water to a very high level (30K to 90K PSI).

Step 2: Abrasive Mixing (Optional)

Near the nozzle, we can opt to mix abrasive into the water stream to increase its cutting power.

Step 3: Focusing and Acceleration

The pressurized stream moves towards the nozzle assembly, which focuses the stream through its small orifice.

Step 4: Cutting Process

The focused stream is pointed towards the material to be cut. On contact, it erodes and removes the material.

Compatibilidade de materiais

Material compatibility is another very important area where waterjet and plasma cutting differ greatly. In terms of the range of materials supported by each method, waterjet cutting emerges as the clear winner.

As we know plasma cutters work exclusively with conductive metals, as these materials facilitate the completion of the electrical circuit required for the operation. Some examples of suitable metals include copper, aluminum, stainless steel, brass and others.

Waterjets, on the other hand, have no such restrictions as they are capable of cutting almost any material, even those with complex shapes. This includes a range of material types such as metals, composites, natural materials, plastics, rubber, paper, stone, and glass.

Velocidade e precisão

Speed and accuracy are both important metrics when it comes to cutting processes, and both plasma and waterjet excel in the field. However, plasma cutting significantly outperforms waterjet cutting in terms of cutting speed.

Waterjet typically operate at speeds of 12 to 15 inches per minute, while plasma cutting can achieve cutting speeds of up to 200 inches per minute. The increased speed of the plasma cutter not only makes a significant difference but also improves the production rate.

Speaking of precision, plasma cutters have a cutting accuracy of 0.01 to 0.030 inches. However, waterjet technology outperforms them with an impressive average cutting tolerance of 0.005 to 0.001 inch.

Espessura do material

When working with materials of standard thickness, both water jet and plasma cutting can work effectively without any problems.

However, if you need to cut thicker materials, plasma cutters are best for cutting materials like mild steel up to 6 inches while waterjet technology can handle any harder material up to 10-12 inches thick.

It is worth noting that recent advances in waterjet technology have made it possible to cut even thicker materials, although this may require more time and may change tolerances.

Plasma Cutter Advantages Over Waterjet Cutter

Plasma cutting has become a widely used technique for metal fabrication jobs and is often preferred over waterjet cutting in many aspects. Some of its advantages over waterjet include:

Low Operating Costs

In terms of upfront and operating costs, plasma cutter has a major benefit over waterjet, with a hourly cost of $15. In comparison, waterjet cutters can cost between $15 and $30 per hour.

Fast Cutting Speed

Cutting speed has a direct effect on production rate. Plasma cutters, with an average cutting speed of about 200 inches per minute, outperform waterjet cutters in terms of speed.

Less Maintenance

Waterjet machines have many consumables and components that require frequent maintenance, ultimately impacting costs. However, plasma cutters require relatively less maintenance.

Low Noise Level

Waterjets make noise due to powerful pumps and pressurized water. Whereas plasma cutters make less noise and cutting underwater can reduce the noise level by another 40 decibels.

Waterjet Cutter Advantages Over Plasma Cutter

Waterjet technology has revolutionized the manufacturing industry by introducing a cold cutting process that replaces traditional methods of heat generation. It offers numerous advantages over heat-generated cutting techniques such as plasma. Its unique benefits include:

No Material Restrictions

Waterjet offer more flexibility because it can cut any type of material, whether it’s hard or soft. In addition, they also have the advantage of being able to handle much greater thickness.

Sem geração de calor

The cold cutting process ensures that there is no heat generation or distortion, and the resulting cut edges maintain a clean and smooth appearance with an excellent surface finish.

High Cutting Accuracy

The waterjet cutting method offers a remarkable tolerance of just 0.001 inch, ensuring unmatched precision. Additionally, it results in narrow kerf width and higher edge quality.

Sem acabamento secundário

The waterjet cutting process produces quality edges that are clean, accurate and burr-free. Therefore, secondary finishing operations on the cut area are unnecessary.

Amigo do ambiente

Waterjet is highly suitable for use in environmentally sensitive areas as it can operate without producing any toxic fumes, hazardous waste or debris and uses a closed loop system.

When To Buy Waterjet Or Plasma Cutter

The performance of water jet cutting and plasma cutting varies depending on the area of application. Each technology has its own unique advantages and disadvantages as well.

So, the decision of which one to opt for ultimately depends on your specific requirements. Here are some of the important factors to consider when deciding between waterjet vs plasma.

Operational Cost

Plasma cutting is a great option if you’re looking to minimize upfront investment and keep operational costs low. Compared to water jet cutters, plasma cutters are more cost effective. Additionally, you can also save on maintenance costs.

Quality of Cut

Waterjet cutting is the ideal choice for those who prefer quality over cost. With waterjet, you can achieve extremely tight tolerances and minimal taper while enjoying clean and smooth edge quality without the need for secondary machining.

Production Speed

Higher cutting speed translates to more cuts in a given period of time, which in turn enhances overall productivity. Now waterjet cutting is generally considered a slow process. While plasma cutting is the most efficient and fastest solution available.

Material Waste

Both waterjet and plasma cutting methods result in minimal waste. However, waterjet cutting typically produces a lower kerf and offers higher accuracy, minimizing the chance of failed cuts and further reducing waste.

Flexibility/Expansion

Although plasma technology can only cut the material for which the machine is designed, waterjet cutting has a wide range of applications and can process a variety of materials. Therefore, waterjet provides more flexibility in the cutting operations.

Waterjet Vs Plasma Cutting Cost

Don’t forget to compare costs between waterjet and plasma cutting when deciding on a cutting technology for your operations. To get a better understanding of what you can expect to pay for either option, it’s important to review the various factors that affect the overall cost.

Custo da máquina:

The upfront cost of any machine is often a deal-breaker for many businesses, and it’s worth noting that there is a major cost difference between waterjet and plasma cutting machines.

You can expect to spend $100,000 to $350,000 on an industrial-level CNC waterjet cutter, which is a substantial amount compared to the price of a professional CNC plasma cutter, which can range from $50,000 to $100,000.

Custo de funcionamento:

It is not uncommon for businesses to overlook operational costs when making the initial calculations to purchase a machine. However, the operational costs associated with waterjet and plasma cutting machines can vary greatly.

Waterjet cutting costs can be quite high, with around 70% of the total cost going towards abrasives. On average, a water jet cutter costs $15 to $30 per hour to operate. In comparison, plasma cutters are slightly more economical, costing around $15 per hour.

Custo dos componentes:

Waterjet cutting machines have high component costs because many parts such as nozzles, focusing tubes, and pump seals wear out over time and need to be replaced. These replacement parts can cost anywhere from $15,000 to $25,000 annually.

On the other hand, while plasma cutters generally require less maintenance, nozzles and electrodes still need to be replaced frequently.

Plasma Cutting Vs Waterjet Cutting: Alternatives

Both plasma and waterjet cutting are undoubtedly the best options for metal fabrication. But it is important to note that there are other alternatives available apart from these which may be better depending on your specific need and application. Here are some of them:

Corte a Laser

The use of laser technology for cutting and engraving materials can be seen everywhere. The main reason behind this is the unparalleled precision and accuracy of this method.

The process of laser cutting can be classified into three different types (CO2, fiber, and diode). Each one operates differently and is best suited for specific applications.

The working of a laser cutter involves the use of a high-powered laser beam that is focused on the material to be cut through a beam delivery system.

The intense heat generated by the laser rapidly raises the temperature of the material, causing it to melt, vaporize or burn, ultimately producing a narrow and precise cut.

Dica profissional: Consulte também o nosso guia pormenorizado sobre corte a laser vs corte por jato de água.

Corte EDM

Electrical discharge machining (EDM) or wire EDM is a widely used technology for cutting processes. This technique is particularly effective for materials that have high conductivity.

With cutting tolerances of this process as low as 0.0001, it produces unquestionably very accurate and precise results.

In this process, the material is removed from the workpiece with the help of electrical discharges or sparks. To achieve this, the workpiece and electrode are submerged in a dielectric fluid.

After that, electrical sparks are created between them. The material at the point of contact is melted/vaporized by the sparks, resulting in clean cuts.

Plasma Cutting Vs Waterjet Cutting Safety

While both waterjet and plasma cutting methods have their own safety risks, they differ in the type of hazard involved.

Plasma cutters use high electric currents and extreme temperatures, while waterjets use a highly pressurized stream of water that can be dangerous if it comes into contact with the operator.

However, waterjet technology is considered a safer option because it uses a cold-cutting method that does not generate high temperatures, open currents, or smoke/dust particles.

That said, proper training and safety precautions are still required when handling either of these two machines.

Plasma Cutting Vs Waterjet Cutting: Which Is Better?

When it comes to deciding between plasma vs waterjet for your business, it’s important to weigh all the pros and cons. In this case, waterjet technology offers many advantages that make it an excellent choice, especially when initial and operating costs are not a concern.

Its greatest advantage is its ability to cut virtually any material known to man using a cold cutting process, which ensures high-quality cuts with no distortion.

Despite its slow cutting speed, you can easily increase your productivity by stacking multiple sheets on top of each other. Additionally, waterjet technology has impressive recycling capabilities that make it an ideal option for a variety of industries.

Overall, waterjet technology provides many long-term benefits that guarantee a high return on investment.

Conclusão

Both waterjet and plasma cutting technologies have distinct operation mechanisms and benefits so it is important to understand each in order to choose the appropriate method for your application.

We hope our guide has helped you gain a clear overview of both waterjet vs plasma cutting technology, including their capabilities and the types of projects each method is best suited for.

In case you still need assistance and wish to have a conversation with the industry-leading CNC experts regarding your specific requirements, market analysis, or the best solutions for sourcing waterjet cutters, feel free to contact IVYCNC hoje.