Projects in the aerospace industry require complex technology and complete precision. Not only is this sector responsible for producing aircraft engines, the aircraft themselves, and related parts; but also military solutions (like guided missiles), scientific developments (like space vehicles), and other components that make up much of our modern world.
As an industry with no margin for error, the aerospace department employs the accuracy and versatility of waterjet cutting to create a range of components — from jet engines and turbine blades, to custom control panels, and more.
In fact, although the concept of waterjet machining may seem quite modern, the waterjet has had a home in aerospace since the 1970’s.
The Need for Precision in the Aerospace Industry
The aerospace industry is diverse and widespread — covering everything from commercial aircraft, to military solutions designed primarily for defense. In production, each component must be carefully machined to the highest possible quality, as even the slightest error or structural weakness could lead to disaster.
Machining parts for the aerospace industry — with a range of high-strength, exotic materials — is more complex than making other consumer goods. Traceability requirements are excessively stringent, and tolerances are much stricter; meaning the industry needs machining processes capable of adhering to highly sophisticated levels of production. In the face of such high standards and manufacturing demands, the waterjet entered the scene and swept away any competition.
The History of Waterjet in the Aerospace Industry
During the 1970’s, aerospace companies were already using pure waterjets when designing interior components for planes — such as carpeting and seats. As the need for more precise solutions became apparent (to manufacture hard materials such as steel, composites, and titanium), the aerospace sector turned to abrasive waterjet cutting for an answer.
When abrasive waterjets made their way into the aerospace industry, Boeing was one of the first companies to adopt the solution, using it to process numerous materials. The organization quickly found that abrasive waterjet machines offered precision, reliability, and strength — especially when fabricating new components that other methods struggled to cut.
Today, almost every aerospace company in the industry uses waterjet technology to design the perfect components and machinery. In fact, you’d be hard pressed to find a plane that has no waterjet-created parts.
What Waterjets Can Offer in Aerospace Production
So, how have waterjets proven themselves to be precise, reliable, and strong enough to meet the tight demands of aerospace production?
In large part, waterjets are favored due to their adaptability. Not only can abrasive waterjets be adjusted to the specific needs of any given part; they can also be standardized for precise, uniform production on a large-scale basis. They are adaptable across projects, and across material types. Waterjets can effectively cut through a range of substances — including materials that may experience damage from other fabricating processes — such as:
- Carbon fiber
- Stainless Steel
The reason waterjets can cut so many differing materials is that they employ a cool-cutting process that leaves no heat-affected zones. Lasers and other tools struggle to effectively cut materials that possess a high thermal conductivity (like steel or aluminum). Waterjet machines, on the other hand, eradicate any heat-affected zones that could lead to microscopic cracks, or structural weakness in components.
Waterjet machines also work alongside control and automation technologies, to make production more standardized and straightforward. Considering the precision required in aerospace manufacturing, this is a huge benefit to companies in the industry. High-tech computer systems ensure parts are fully and carefully constructed, right down to the smallest possible detail. Though laser machines can also use computerized systems, the heat they impose on materials can lead to warping, which then requires secondary processing.
Added Benefits of Waterjet Technology
Waterjet cutting is one of the most versatile manufacturing solutions in the world — capable of delivering a clean, smooth cut that requires minimal additional fixturing. For the aerospace industry, this means efficiently producing parts that don’t suffer from structural issues, through a process that is:
- Environmentally friendly, and capable of reducing hazardous dusts and gasses
- Flexible in terms of machine integration
- Able to save on raw materials
- Faster than a number of conventional cutting tools
- Omni-directional (capable of cutting in various directions)
Once you look at all the capabilities and benefits of waterjet technology, it seems like a no-brainer that this is the machine of choice for the companies making our planes, jets, military devices, and space vehicles.
Waterjet technology represents one of the fastest growing areas of manufacturing in the world — thanks to the fact that it’s highly versatile, effective, and precise. Capable of cutting through almost any material with extreme accuracy, waterjet cutting is a fabrication process that can provide essential solutions when other methods — such as lasers, and traditional cutting — simply aren’t applicable to the project at hand.
At a basic level, a waterjet is a cutting tool used to shape materials with a high-pressure stream of water. If the water stream includes an abrasive, it becomes more powerful, and can cut tougher materials.
At a more detailed level, we’ll outline how waterjet technology works on a deeper basis — explaining how each essential component in these innovative machines work together to create intricate, accurate cuts.
Defining the Cutting Capabilities of Waterjet Technology
Before we cover the components of a waterjet machine, it’s important to note that there are two main types of waterjet machining available — and the differences between these types distinguish what each machine is capable of.
- Pure Waterjet Technology
Pure waterjets cut softer materials; such as foam, rubber, leather, textiles, and even cakes and vegetables. Though these machines contain many of the same components as their counterparts, they do not include the abrasive materials in the water stream. In a pure waterjet, the stream can move at a velocity of up to 2.5 times the speed of sound.
2. Abrasive Waterjet Technology
Abrasive waterjets shape harder materials that cannot be cut using water alone. In these machines, engineers replace the water nozzle of pure jets with an abrasive cutting head. The high-velocity stream draws the abrasive into a mixing chamber, to produce a powerful blast of erosive water. Abrasive jets can cut various materials; including sheet metal, aluminum, stainless steel, and concrete.
The Components of Waterjet Machines
Though abrasive and pure waterjet machines differ in cutting capabilities, the primary components that work together within the machine remain largely the same. In both circumstances, waterjet cutting involves the movement of water at extremely high pressures through a small diameter nozzle.
Most waterjet systems contain the following components:
- High pressure pump — This pump generates a flow of pressurized water for cutting.
- Articulated cutting head — This multi-axis cutting head is capable of permitting various angled cuts, and precise vertical machining.
- Abrasive nozzle, or pure waterjet nozzle — Depending on the purpose of the machine, the nozzle either works as a medium through which to mix water with abrasive substances, or simply a focus point for a pure water stream.
- Catcher tank — Filled with water, the catcher tank dissipates the energy of an abrasive jet, after it cuts through the material.
- Abrasive hopper — Only used in abrasive waterjet machines, the hopper controls the flow of granular abrasive into the nozzle.
- Traverse and control system — This precise system accurately moves the nozzle through the correct cutting path. In some instances, this will come in the form of an advanced, PC-based motion controller.
The Waterjet Cutting Process
With the components outlined above all working harmoniously, waterjet machines cut materials using the same principles as natural water erosion — only at a much more concentrated, accelerated level. Water lands forcefully upon the surface of a material, in order to loosen and wash away unwanted particles.
The standard waterjet works through a process of important steps:
Step 1: Gathering Water
The process begins when a large electric pump draws water into the system, at a high pressure rate. The machine stores the water within a heavy-duty intensifier assembly, to amplify the existing pressure.
Step 2: Increasing Pressure
Inside the intensifier system, the water pressure increases to a level that usually falls between 20,000 and 55,000 psi (pounds per square inch). This increase in pressure comes from pistons within the system.
Step 3: Sending Water through an Orifice
The ultra high-pressure water is then drawn through stainless steel pressurized piping, into a cutting head — where it is focused through a sapphire, ruby, or diamond orifice between 0.010″ and 0.015″ in diameter. This turns the stream of water into a fine needle of cutting power.
Step 4: Adding Abrasive
In an abrasive waterjet, the water passes through a mixing chamber, where the pressure of the stream draws abrasive into the water. The mixture of abrasive and water passes through a ceramic mixing tube, before exiting the nozzle as a stream of high-power cutting particles.
Step 5: Exiting the Cutting Head
Either with or without abrasive, the water (or water mixture) exits the cutting head through a focusing tube, at speeds that can reach up to Mach 3 (three times the speed of sound).
The end result of this precise process? Depending on your project, it may be a set of artistic geode bookends, a meticulously-designed and fitted motorbike helmet, or a row of perfectly sliced pastries.
For centuries, the human race has turned to the powerful forces of nature to achieve feats of engineering and creation. From sawing logs, to milling flour, weaving textiles, and even generating power, water has long proven to be a versatile and useful ally in the manufacturing world.
Water can easily wash away hills and shape mountains, through erosion — and from this natural process, the idea to create an accelerated machining solution emerged. From the promising waterjet solutions of the past, to the innovative and comprehensive waterjets used across the world today, there’s almost nothing water can’t do.
Waterjet cutting is one of the fastest growing methods of machining in the world — capable of profiling a huge array of materials. Let’s take a look at how this precise cutting process got to where it is today.
Where Waterjets Began
Waterjets officially emerged for the first time during the early 1800’s — when coal miners from the Soviet Union and New Zealand used pressurized water, diverted from streams, to remove loose debris and coal. During the Gold Rush of the mid-late 1800’s in California, the same concept was put to use; pressurized water excavated gold from soft rock, and directed it downstream for pan-wielding miners. Though hydraulic mining isn’t the primary function of waterjet machines today, it marks the start of a series of inventions that lead to water’s current role as an industrial cutting device.
In the 1930’s, waterjet technology found a purpose cutting materials like paper, using a jet-stream technique created by Leslie Tirrell and Elmo Smith. After time, innovators began to see the benefits of adding abrasives to a waterjet stream, in an attempt to cut harder materials. While the initial lifespan of abrasive waterjet nozzles was too short to be commercially viable, these new designs prompted the creation of new mixing tubes and materials, designed to make waterjet machining stronger — and more reliable than ever.
The Evolution of High-Strength Waterjets
In the post-war era, researchers and manufacturers across the globe continued to seek new methods of efficiently cutting materials. In the 1950’s, a forestry engineer called Dr. Norman Franz experimented with ultra-high pressure water systems, in an effort to cut trees to lumber. His experiments showed that abrasive waterjets could effectively cut harder materials.
In the mid-1960’s, research into traditional waterjet cutting by G.L. Walker, and S.J. Leach helped to determine the ideal shape of waterjet nozzles. The 1970’s saw the invention of crystal waterjet orifices — created by the Bendix corporation — which helped develop the very first mainstream waterjet cutting system on a commercial level.
This new waterjet system could achieve pressures of up to 60,000 PSI — meaning that a jet of approximately 0.1mm diameter could slice and dice anything from food products to paper. Though these waterjet machines were expensive — and required a lot of maintenance — they were still regarded as more cost-effective than traditional methods of cutting softer materials.
The Waterjet Today
By the end of the 1980’s, the Boride corporation had developed mixing tubes composed of a ceramic, tungsten, and carbide compensate. These carefully designed tubes could withstand the erosive pressure of abrasive waterjets, transforming the unreliable process of the 1930’s into a viable solution for the future of manufacturing.
Flow International, Inc. became the first company to sell a waterjet machine to an automotive manufacturer — and others quickly followed suit. Over time, intensifiers emerged to develop a more consistent pressure within waterjet machines; while new components allowed experts to measure the amount of abrasive they were using. Each new innovation has made waterjet technology more affordable and reliable within the manufacturing industry — allowing its popularity to grow and blossom.
The waterjet’s capabilities are still evolving, as diamond orifices replace sapphire orifices, and standard nozzles transform into composite carbides. The manufacturing industry is continually seeking to make the process more precise, reliable, and accessible — when it comes to sheer power, we may just be floating on the surface of what water can do.
Do you have any predictions for the future of waterjet cutting? Let us know in the comments below!
Waterjets can cut metals, plastics, foods, and even carbon fiber — without any risk of warping or distortion. As the popularity of waterjets increases, there are some misconceptions floating around the industry, that may leave you confused as to what a waterjet machine is actually capable of.
To help you better understand the process, here are a few of the most common myths associated with waterjet cutting:
1. Waterjets Struggle to Cut Complex 3D Parts
Some people believe that although waterjets can easily cut precise designs into flat pieces of material, they fall short when it comes to dealing with 3D components. The truth is that recent advances in the realm of XD three-dimensional cutting have maximized the versatility of this promising fabrication method.
Using a cutting head that can swerve in multiple directions — controlled with advanced software — allows waterjets to cut complicated 3D parts in a single, fluid motion; removing the need for secondary cutting.
2. Abrasive Waterjets Are Messy, Noisy, and Slow
It makes sense that people assume the results of waterjet cutting take a lot of time and effort to produce — after all, they’re quite astounding. However, waterjet cutting uses a process of accelerated erosion to slice through material — usually in a very short space of time.
This fast cutting speed doesn’t actually lead to additional problems in mess, or noise. Cutting under a small amount of water can reduce the presence of mist, steam, or spray — particularly when manufacturers use a pierce shield at the same time. Underwater cutting also serves to reduce noise levels! While cutting above water can lead to noise pollution of 95 decibels (depending on the distance between the material and the mixing tube), underwater cutting reduces that level to only 75 decibels.
3. Waterjets Use Excessive Force to Pierce Materials
While it’s true that waterjets use significant pressure to create impressive cutting results, the force might not be as high as you think. On average, an abrasive waterjet produces between 20,000 and 55,000 pounds of water pressure PSI — about 30 times the pressure you might see at your local car wash. Although they can get up to 55,000 pounds, the amount of force exerted by a standard waterjet machine is usually only between 15 and 40 PSI.
4. Garnet Mesh Doesn’t Affect Speed
Most people in the manufacturing world know that garnet is necessary to create an abrasive waterjet capable of cutting through hard metals — but many don’t recognize the importance of the garnet mesh, in regards to the speed of the cut. Garnet abrasive is used in most waterjet machines, typically ranging from 50 mesh to 220 mesh.
In waterjet cutting, the size of the abrasive particle translates to the speed of the cut. That means that 50 mesh is likely to cut a little faster than 80 mesh, at the same flow rate. On the other hand, if you were to switch to a very fine abrasive — designed for use with special cutting, and smooth edge production — you might find that the process is a lot slower.
5. Fixturing Parts is Unnecessary
The force used in waterjet cutting may be less than you expect, but it’s still quite a force to be reckoned with — it’s important to use fixtures to hold a piece of material in place. Fixtures keep the workpiece carefully situated within the machine, to reduce the chances of unwanted movement and ruined designs. It’s very easy for a piece to move during production — which can waste both time and resources.
6. Striations Will Always Happen
It’s true that striations — the furrows and linear marks that appear on fabricated materials — can occur during the waterjet process. However, this outcome usually occurs as a result of a number of extraneous factors; which can be controlled during cutting. For instance, maintaining a consistent amount of power through the machining process will create a smoother finish. Oftentimes, the faster you cut, the more striation marks will form. The material you use can be important, too — irregularities in pieces of metal, or plastic, can quickly lead to unexpected marks.
7. Waterjets Can Cut Through Anything
The materials a waterjet can effectively cut through will depend largely on the type of waterjet you’re using. While pure waterjets are best suited to softer materials, the precise cut they produce won’t work with metals, or tougher parts. Alternatively, abrasive waterjet technology can extend the benefits of waterjet technology to harder materials — ranging from steel, to carbon fiber, and more!
The Truth about Waterjets
Today, most fabrication and manufacturing experts are aware of the benefits of using waterjets to shape and structure parts. These innovative solutions produce very little waste; while contributing to the creation of smooth edges, precise parts, and quick, efficient results. In fact, when compared to laser and plasma cutting, waterjets provide the added benefit of leaving no heat affected zone to damage the materials.
What do you think are some of the most common misconceptions about waterjets? Has our list helped to clear up your understanding of the waterjet world? Let us know in the comments below!
Although pure waterjet solutions are still used to cut soft materials (like paper and food), most manufacturing companies use abrasive waterjets to shape parts and components. In an abrasive waterjet system, the efficiency of the cut is about more than just hitting material with pressurized water — it’s also about selecting the correct abrasive, designed to cut through the material as cleanly as possible.
While garnet is the most common choice for waterjet grit — providing the hardness needed for clean, powerful cuts in even the most intricate of designs — this abrasive comes with flexibility, in regards to the grit size. Depending on what you’re cutting, the types of cut you’re making, and the intricacy of each cut; you have a crucial decision to make before you start the waterjet process. A larger grit won’t produce the same results as a smaller grit.
Choosing the right size grit for your waterjet project can minimize the consumption of abrasives, reduce unnecessary costs, and maximize productivity on the manufacturing floor.
The Factors Involved in Choosing Grit Size
Commonly, fabricators will have a selection of “mesh” grades they can choose from, when selecting the perfect abrasive (or grit) for a waterjet project. Each “mesh” grade represents a different grit size — and although they might not dictate the exact dimensions of each particle, they do give some insight into the general distribution of grit size.
There are three mesh grades that commonly appear on the waterjet market. These include:
- 50-60 mesh — This covers larger sized particles, and tends to be for rougher grit applications.
- 50-80 mesh — The common standard, known as “moderate” grit.
- 100-220 mesh — The smallest grit size, for the finest possible particles.
Of these options, the 80 mesh solution is the most popular, for the majority of “general” projects.
How Grit Size Determines Your Project Results
Knowing the grit sizes available is one thing, but understanding how those grit sizes affect your project is another matter. Typically, the bigger your grit size, the rougher the cut will be. Smaller grits are for finer, more precise details — which means that your ideal abrasive will depend on what you’re trying to achieve in the machining process.
The grit size impacts a variety of factors, including:
- Expenditure — While the cost of the materials for your project might not be the most important factor, it’s worth thinking about when choosing grit. Smaller mesh batches are generally much more expensive than larger grits; so, depending on the mesh you’re looking to use, your project could become costlier.
- Speed and efficiency — The larger the grit size, the faster the cutting process will be. This means that a 50 mesh will often blast through materials faster than an 80 mesh; but it may also mean that you have to compromise on other things — such as surface finish.
- Surface finish — If you are jetting with the hope to avoid secondary finishing procedures, the grit size you use is essential. Smaller grit will always lead to a finer, cleaner finish than larger grit. This means that a polished surface aesthetic requires a far smaller grit size.
Problems with Choosing the Wrong Grit Size
While it may seem simpler to choose an 80 mesh because it’s most popular, or stick to the least expensive grit you can find, selecting the right abrasive for your particular project is essential to achieving the results you want. The wrong abrasive can not only damage your components, or waste materials; it may also damage your waterjet machine by clogging the nozzles, and delaying productivity.
Clogs can easily occur in waterjet machines, as a result of too much abrasive, or a mesh size that’s too large for a specific orifice diameter. Regardless of which grit size you choose, make sure that it not only suits your project, but the other parts of your machine too. Always use the correct nozzle/orifice combination, and select the proper orifice for the grit size you need.
Waterjet Abrasives and Cutting Performance
Grit size will not be exclusively responsible for your waterjet cutting experience — pressure settings, nozzle sizes, and orifices must all be considered, as well — but it does play a crucial role. Tailoring your grit size to your specific project will help you to get the best results possible, while structuring each cut in a way ideal for streamlining workflow. Choosing the appropriate grit size is essential to getting the perfect results you need, for a cost-effective and efficient fabricating process.
Which are your preferred grit sizes, and why do you like using them? Have you found that specific grit sizes work best for certain projects? Let us know in the comments below!