How Does Waterjet Cutting Work? (Helpful Guide)

Waterjet cutting is a versatile and efficient technology used in various industries for cutting a wide range of materials.

This comprehensive guide will dive into the details of how waterjet cutting works, its components, types of waterjet cutting, the advantages it offers, and the vast array of applications it serves.

The differences between waterjet cutting and using a plasma cutter are that waterjet cutters can be:

More accurate
Last longer
Have no heat-related effects
Can cut a wider variety of materials
Can cut layers and indents
More environmentally friendly

There are many factors in determining whether you want to use a waterjet machine or a plasma cutter table. You will need to identify your priority values so you can choose the best plasma cutter or the best waterjet cutter for your individual needs.

Table of Contents

How Does Waterjet Cutting Work?

Waterjet cutting is an advanced process that utilizes high-pressure water, or a mixture of water and abrasive material, to erode and cut through various materials. The technology is limitless in terms of the materials it can cut, making it a popular choice in many industries.

The Basics of Waterjet Cutting

The concept of waterjet cutting is relatively simple and consists of the following steps:

Generate Pressure: An ultrahigh-pressure pump generates a stream of water with pressure rated up to 94,000 psi (6,480 bar). This pressure is significantly higher than that of a fire hose, which ranges from 390 to 1,200 psi (20 to 84 bar).
Convert Pressure into Velocity: The high pressure is converted into velocity through a tiny jewel orifice, creating a stream as narrow as a human hair, capable of cutting soft materials.
Introduce Garnet: To increase the cutting power by 1,000 times, garnet abrasive is introduced into the supersonic waterjet stream. The water and garnet mixture exits the cutting head at nearly four times the speed of sound, enabling the cutting of hard materials like steel, ceramic, stone, glass, and composite.

Pure and Abrasive Waterjet Cutting

There are two primary types of waterjet cutting: pure and abrasive. These technologies can cut virtually any material, shape, and thickness.

Pure Waterjet Cutting

Pure waterjet cutting is used for soft materials such as gasket, foam, plastic, paper, disposable diapers, insulation, cement board, automotive interiors, carpet, and food. The process involves using high-pressure water alone, without the addition of abrasive materials.

Abrasive Waterjet Cutting

Abrasive waterjet cutting is similar to pure waterjet cutting, but with the addition of garnet abrasive into the water stream. The resulting abrasive waterjet stream is capable of cutting hard materials like metal, ceramic, stone, glass, and composite.

Components of Waterjet Cutting Systems

A waterjet cutting system is composed of three main components:

The Ultrahigh-Pressure System: This includes the pump, cutting head, and plumbing responsible for generating the high-pressure water stream.
The Machine: This consists of the X, Y, Z axes, cutting head wrist axes, and material support catcher that provide precise movement and control during the cutting process.
The Control System: This includes the programming software, operator interface, drive motors, and position and velocity feedback system that govern the overall operation of the waterjet cutting machine.

Types of Waterjet Cuts

Waterjet cutting machines can perform a wide variety of cuts, depending on the needs of the application. They are capable of performing traditional single cuts as well as 2, 3, 4, and 5-axis cuts.

One Dimensional Cuts

One-dimensional waterjet cuts are stationary cuts performed in a single pass of the workpiece through the waterjet cutting mechanism. They are the simplest form of cut and are used for trimming. The operator feeds the workpiece into the cutting tool while the debris and water are caught on the other side.

Two Dimensional Cuts (XY)

Two-dimensional cutting requires the use of PC or CNC programming. These machines have a servo motor with closed-loop feedback to control positioning and cutting velocity. Catcher tanks are water-filled and have slats to support the workpiece. The Z-axis controls the height of the cutting device to adapt to variations in the thicknesses of the workpiece.

Three Dimensional Cuts (XYZ)

Three-dimensional cutting involves the use of the X, Y, and Z axes to maneuver the cutting tool along the three planes. In this process, the workpiece remains stationary while the cutting tool moves accordingly. This cutting method is commonly used to produce mechanical components.

Four Dimensional Cuts (XYZA)

Four-dimensional cutting utilizes the X, Y, and Z axes along with an additional A axis, which provides a fourth-dimensional rotary motion around the X axis. This additional axis allows the workpiece to be cut along the B axis, making it ideal for creating cuts in the sides of a workpiece or holes.

Five Dimensional Cuts (XYZAB)

Five-dimensional cutting enables the workpiece to be manipulated along five axes simultaneously. The workpiece is moved along the two-dimensional XYZ axes, with additional rotational movements added that travel around the XYZ axes. These are the A, B, and C axes, which perform 180-degree rotations around the X, Y, and Z axes. This cutting process allows for the fabrication of extremely complex solid components.

Types of Waterjet Cutting

Though the concept of waterjet cutting is simple, its application varies widely. The many variations have been developed to meet the exact specifications for different applications.

Abrasive Flow Machining (AFM)

Abrasive flow machining is an interior surface finishing process used for deburring and honing parts that traditional deburring methods cannot reach. The water and abrasive mixture erodes the surface, removing unwanted particles in a manner similar to a grinder or sandpaper.

Abrasive Jet Machining

Abrasive jet machining incorporates a high-pressure stream of water with an abrasive to blast and erode the workpiece. This process is used to cut intricate shapes and form smooth, even edges. Abrasive jet machining is ideal for cutting brittle, thin, and hard materials.

High-Pressure Water Cutting

High-pressure water cutting involves intensifying the water flow using hydraulic pumps that harness the force of the water and convert it into mechanical energy. The incorporation of corundum elements in the cutting head, such as rubies and sapphires, further enhances the cutting process.

CNC Water Jet Cutting

CNC water jet cutting combines the precision of CNC programming with the capabilities of water jet cutting. This technology is commonly used in situations where the material being cut is sensitive to high-temperature processes. CNC water jet cutting machines offer rapid and precise cutting of various materials and parts.

Portable Water Jet Cutting

Portable water jet cutting machines provide a low-cost, environmentally safe, and flexible cutting method for cleaning contaminated surfaces, removing burrs, and cutting off rust. These machines are suitable for use in hazardous conditions, such as the oil industry, construction tunnels, and pipelines.

Uses for Water Jet Cutting

Waterjet cutting has gained popularity due to its precision, fast turnaround times, and the quality it offers. Numerous industries rely on this technology for cutting various materials with exacting tolerances.

Aerospace Industry

Highly precise components are required in the aerospace industry, and waterjet cutting is an essential part of producing these components. From manufacturing jet engines to custom-designed control panels, waterjet cutting offers the necessary accuracy and efficiency.

Automotive Industry

Waterjet cutting can be integrated into robotic systems, making it a popular choice in the automotive industry. Pure waterjet cutting is used for shaping interior carpets, insulation, and head linings, while abrasive waterjet cutting is used for cutting steel, brass, Inconel, and aluminum.

Medical Industry

Waterjet cutting technology is being used to replace surgical cutting tools, providing a safer and more efficient method for dissecting human tissue with less trauma, bleeding, and postoperative problems.

Glass Cutting

Waterjet cutting is ideal for cutting glass without damaging its internal structure. The high-pressure water stream creates pinpoint accuracy, making it capable of cutting holes, notches, and structures without distortion.

Industrial Cleaning

Waterjet cutting is used for cleaning industrial equipment, storage units, and piping by removing built-up flakes, scales, and rust. The high-speed, pulsating blast from a water jet cutting device can safely remove and clean these surfaces without causing damage.

Food Industry

Waterjet cutting is a USDA-approved method for cutting food products, offering productive and sanitary benefits. The technology can cut meat, fish, poultry, pastries, and frozen foods with precision and speed, ensuring portion control and compliance with strict cleanliness standards.

Electronics

Waterjet cutting is used to cut circuit boards and strip wires without damaging the components. The precision and efficiency of this technology make it a cost-effective choice for electronics production.

Fiberglass Cutting

Waterjet cutting can shape and form fiberglass without creating dust or waste. The process is suitable for shaping insulation and boat parts, providing clean cuts without damaging the material’s grain.

Advantages of Water Jet Cutting

Waterjet cutting offers numerous advantages over other cutting methods, primarily due to its cold cutting process that doesn’t generate heat or alter the material’s molecular structure.

Extreme Precision

Waterjet cutting offers exceptional precision and accuracy, with a cutting accuracy between ± 0.003 inch to ± 0.005 inch. The cutting speed can be altered mid-cut, allowing for parts with multiple edges to be cut accurately.

Secondary Finishing

Waterjet cutting produces smooth, burr-free surfaces without the need for secondary finishing. This is due to the erosion-based cutting process that doesn’t generate heat or shearing forces.

Versatility Advantage

Waterjet cutting is capable of cutting any material, regardless of its hardness, making it a popular choice for various industries. Additionally, thin materials can be stack-cut for increased efficiency and cost savings.

Environmentally Safe

Waterjet cutting is an environmentally friendly cutting method that doesn’t produce toxic gases, harmful waste materials, or poisonous contaminants. The technology uses pure water and natural abrasive materials, while leftover matter can be safely discharged.

Ease of Use

Waterjet cutting is a simple process that involves using a water pump and cutting tool to produce a high-velocity water stream. The same components are used to create any type of cut in any material, making waterjet cutting a cost-effective and economical production method.

Programming Shape

Waterjet cutting machines can be programmed to produce precise positioning, cutting speed, and cutting angle, ensuring accurate cuts for various applications.

Cost Savings

Waterjet cutting offers significant cost savings compared to other cutting methods. The low running costs, fast transition times, and ease of setup contribute to its cost-effectiveness.

Lack of Chemicals

Waterjet cutting does not involve the use of chemicals, cutting tools, or materials that could contaminate the workpiece. This makes it safer for workers and operators, as well as environmentally friendly.

Water Jet Cutting Efficiency

Waterjet cutting is the most efficient cutting method due to its power and handling of materials. Its efficiency is further enhanced by the recycling of water and the elimination of secondary processing.

Product Control

Precision water jet cutting offers better control of the cutting process, allowing workpieces to be cut to the required sizes and dimensions. This control makes water jet cutting more manageable than cutting with a blade or saw.

Sanitary

Waterjet cutting is ideal for the food industry, as it does not involve chemicals or cutting tools that could contaminate food products. The technology ensures compliance with strict cleanliness and sanitation standards.

In conclusion, waterjet cutting is a powerful and versatile technology that offers numerous advantages across various industries. With its ability to cut virtually any material with precision and efficiency, it has become an essential tool in today’s manufacturing landscape.

The Differences Between Waterjet and Plasma Cutting

When determining which type of cutter to utilize, you must understand what areas each of these cutters excel in and what areas they are lackluster compared to their counterpart.

The following categories will detail the differences between plasma cutting and waterjet cutting in many different circumstances. These are the categories that cover almost all the things one would need to think about when determining what method of cutting you need to use. They are ranked in a mindful way, in an attempt to mimic the reasoning you would use when considering which cutting system you want.

This article will be focused on non-industrial size cutters, which end up costing $500,000 and up just for the machine. We will focus on cutters that are:

Small
Portable
Do-it-yourself cutting
For your small business
Non-industrial

…since most industrial cutters are quite expensive and out of the price range of most people and companies.

Cost

First and foremost is the price. Price is the most important thing to consider when you are choosing whether to buy a plasma cutter or a waterjet cutting machine. If you find the perfect machine that checks all the parameters you need, and it is out of your price range, all that time you spent researching is wasted.

The price must always be at the forefront of your mind when looking at the two types of machines.

The average price of your “garage-type” plasma cutter will range from $1,000 for hand-held machines to $50,000 for machines that are programmable. The higher-end price range is geared more towards small businesses that regularly need plasma cutting done.

Plasma cutters come in either hand-held apparatuses or plasma cutting tables, which are the ones that are programmable to cut out specific designs. The tables start out at around $15,000 for the cheapest and run upwards of $50,000 plus.

Waterjets are much more expensive when compared to plasma cutters because waterjet cutters need an Ultra High Pressure Intensifier pump, which accounts for the vast majority of the price bump.

The cheapest water cutting desktops come in at around $10,000, which are the most basic platforms and are able to cut thin materials in simple patterns. More complex machines that are able to cut thicker materials will end up costing $100,000 and up. These expensive machines typically have a free jet head that allows them to cut diagonally and at many angles to get the product you need.

Overall, there is a very wide range of prices for both of the systems. But, getting an idea for the price range of machines is the first step anyone must take when determining to buy either a waterjet cutter or a plasma cutter machine.

Range of Cuttable Materials

After you have gotten an idea of the price range that you can afford for each machine, you need to make sure that the machine you want can cut the materials you will be working with. In this category, waterjet cutters are undoubtedly the superior choice.

Knowing what material each machine can cut is essential is choosing what machine to buy. There is no point in buying the machine and finding out that your machine cannot cut the material you need to cut.

Waterjet cutters can cut almost any material on earth. Common materials that are cut include:

Steel
Aluminum
Styrofoam
Copper
Rubber
Textiles
Food
Paper

Yes, it can cut literally almost any material on the planet! This makes it extremely flexible when you install one in your garage or shop. You can use the machine to make precision cuts on almost anything imaginable, which makes the machine a very useful product to have around.

Most people turn to this plus of the waterjet systems when determining what to buy since it offers a huge benefit compared to plasma cutting technology.

Plasma cutters can only cut conductive metals, which severely limits its ability compared to a water cutting system. Conductive metals still cover the majority of materials you will work with in machining and cutting, but when you need something cut that is not a conductive metal, you are out of luck. Conductive metals include:

Copper
Aluminum
Steel
Alloys
Titanium
Gold
Stainless steel

The reason plasma cutters can only cut conductive metals lies in the way that they make the cuts. Plasma uses electrons that bind to a gas to create the plasma arc. The electrons have to move to the metal to create the heat that makes the plasma be able to cut. It is not so much as a cut, but more of a targeted melting of that particular part of the metal. The electrons need a positive charge metal in order to make the jump from the arc to the metal that makes the cut.

Fast Extreme Water Jet Cutter Machine Working >> Check out the video below

https://youtu.be/sIEqXbXxpfg?t=10

Complexity of Cuts

When you consider what type of machine to buy, you need to keep in mind the complexity of the cut that you will need to make for your specific desire. You may need cuts that are:

At an angle
Indentions
Not full through cuts
Have a smooth cut edge

When considering these things, waterjet cutting again proves to be superior to the plasma cutting method. Waterjet cutting gives the user more flexibility overall than what plasma cutting allows.

Waterjet cutting machines give the user unmatched customization and flexibility when cutting materials that are not present in any other form of industrial cutting. Waterjet cutting allows the user to be able to cut complex shapes that can be of any design.

The more complex waterjet cutting machines are able to choose what pressure to use to precisely cut indents in your metal or not cut all the way through your material, making it a highly sought after machine.

When compared to plasma cutting machines, waterjet machines blow them out of the water in their ability to perform complex cuts. Plasma machines are again limited by their way they cut the conductive metals.

Since plasma cutting machines essentially melt the material they are cutting, it is virtually impossible to not cut all the way through the material you are cutting and make the perfect desired design.

However, this aspect of plasma cutting can perfectly fit the type of cutting some people may be doing, and, for the low price, it can draw people to choose plasma cutting over waterjet cutting. These people do not need to cut extremely complex designs but need relatively simpler cuts.

The simplicity of the cut for the low price draws many people to choose the plasma cutter over the waterjet cutters simply because they want a cheap machine that will get the job done.

Accuracy

When you are cutting your materials, you want to be sure that the machine is cutting at the correct parameters, or your piece will be wasted. Most machines already are programmed to account for the amount of material their cutting stream will take off when they begin to cut, which helps tremendously with the accuracy of the cuts.

However, even with the advanced computer software, waterjet cutting again performs better than the process of plasma cutting.

A waterjet system, on average, has a cut accuracy of +/- 0.005 of an inch. Waterjet cutting machines come with a kerf width or width of the material that the stream will take completely out of the material, at 0.035 of an inch. The accuracy of waterjet cutting is unmatched in the cutting industry.

This makes waterjet cutters the preferred method in shaping and manufacturing small components of many finished goods such as:

Smartphones
Cars
Electronics
Gears
Machine parts
And many more small parts

When compared to plasma cutting machines, waterjet cutters are up to four times more accurate than the plasma cutting machines. Plasma machines have an accuracy, on average, of +/-0.020 of an inch and a kerf size that is roughly four times that of a waterjet kerf at 0.150 of an inch.

Again, the source of this negative attribute comes from the way plasma cutters cut. Plasma cutters also have another negative attribute that comes with the heat generated by the cutting process. Plasma cutting can potentially heat warp thicker metals that you cut. When the metal becomes warped, it is essentially useless and a wasted piece.

Plasma cutting machines again come up short compared to their waterjet cutting counterparts, but one cannot forget the cost difference of the machines. It is because they are not as accurate, flexible, and lack the ability to cut complex cuts that waterjet machines can make, plasma cutting machines are much cheaper.

Longevity

When you buy your cutter, you would want to know how long the parts of the cutter last before they have to be replaced, which can lead to a higher cost to operate. There is no point in buying a cutter that is super cheap, but you end up having to replace expensive parts on it quite often. This is another vital question you must be asking yourself when considering whether to buy a waterjet cutting machine or a plasma cutting machine.

Here, we again have a clear winner, the waterjet cutter. The waterjet cutter, because it does not generate nearly as much heat as a plasma cutter, lasts significantly longer than any plasma cutter, by a massive margin. Waterjet cutting machines also do not have nearly as many moving parts compared to a plasma cutting machine, which accounts for the vast difference in the lifespan of parts.

Waterjet cutting machines can last between 500 hours to upwards of 2,000 hours of work before parts begin to need to be replaced. This is solely due to the two factors mentioned above; lack of heat generation and very little moving parts. You can further this lifespan by buying a waterjet cutter that is made to be inserted into a tank of water to further reduce the amount of heat produced when cutting.

The source of this difference in longevity again comes from the plasma cutter’s process by which it cuts metal. Plasma cutting machines use intense heat, 40,000 degrees Fahrenheit, to melt the metal that they cut.

To generate this immense amount of heat, there are a lot of moving parts that are inside all plasma cutting machines that get up to very high temperatures and can even begin to melt. The heat is the main reason why plasma cutters have such a short lifespan.

The range of the lifespan of plasma cutting machines can be extremely varied because it relies on what type of work you are doing with the cutter itself. If you are cutting:

A thicker metal
For long periods of time
Often
Certain types of metal

All of these determine the lifespan of your plasma cutting nozzle, which will be the main thing that needs replacing on your machine. If you have a greater value of the first three factors on the list, then the lifespan of the plasma cutter is reduced.

Plasma cutting steel >> Check the video below

Cut Speed

Cut speed is essential in determining what type of cutter you need. The speed at which you will cut determines how many items you can cut or how productive you can be. When you cut faster, you save time, and, as we all know, time is money.

In this category, plasma cutting machines clearly outpace their waterjet cutting counterparts. Aspects of the material that directly impact the speed at which you are able to cut for both systems are:

Thickness of material
Desired accuracy
Complexity of cut
And the type of material

Overall, plasma cutting machines can cut at a blistering rate of 60 to 200 inches per minute. This may sound slow, but in the cutting industry, it is extremely fast. Again, the variability comes from the four variables aforementioned.

If you have a thicker metal, it will take longer to cut with any type of cutter. If you want greater accuracy, you will need to cut at a slower rate. If you want to cut a more complex shape or design, you will need more time to cut this design. Also, there will be a great variance in cut time if you want to cut metal vs. Styrofoam for a waterjet cutter, you will find it much quicker to cut the softer material than the metal.

Waterjet cutters cut at an extremely slow rate, at least four times slower, at a rate between 15 inches per minute down to a fraction of an inch per minute. This makes plasma cutting machines much more efficient in cutting when you look at saving time for each cut. You are able to perform more cuts, in a quicker amount of time, at an overall cheaper cost using a plasma cutter compared to a waterjet cutter.

Environmental Impact

Now that we have gotten through most of what comes to mind when you are thinking about purchasing a cutting machine, you also have to think about the environmental impact that the cutter that you choose will have.

Waterjet cutters are the clear victors in this regard. Waterjet cutting machines have very little environmental impact when they cut and during operation. The water itself is easily able to be recycled and put down a drain. In regard to the material itself, the kerf that the waterjet has allows you to save more material than the plasma cutting machines.

Where waterjet cutters fall behind plasma cutting machines is that waterjet cutting machines produce a lot of noise pollution. They are extremely loud. As more studies come out saying that noise pollution is detrimental to the environment and to the health of people, one must also think about the noise produced by the machines they are operating.

The noise level can be greatly reduced by putting the waterjet cutter into a tank of water to operate in.

Plasma cutting machines produce a toxic gas when they cut the metal. The toxic gas is very acidic and has many hazardous materials that are a by-product of the cutting process. Studies have been conducted to show the continuous inhaling of this toxic smoke does damage the lungs of the user.

Conclusion

When deciding what type of machine you want to use, you must consider the categories outlined in the article. Price, above all, is most important, as it is when deciding to purchase any expensive item.

When looking at a plasma cutting machine, you should choose one if you want a:

Cheaper machine
Not performing complex cuts
Only cutting conductive metals
Faster cut speeds

You should choose a waterjet cutting machine when you:

Want a more accurate cut
Performing complex cuts
Want a longer-lasting machine
Has a lesser environmental impact