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 most companies, success relies on the ability to offer customers a consistently impressive product.
When the foundation of your organization is built upon quality, you can gain a competitive edge, and ensure that sales numbers and profits continually thrive. Quality contributes to customer loyalty, positive brand recognition, and repeat business — and increases the chance that customers will recommend your business to others.
Unfortunately, on the production floor quality control can quickly become lost in the rush of machining; often slipping through in the urgency to get completed projects out the door, while minimizing costs and maximizing profit.
How can you maintain quality control without losing profits? The solution relies upon streamlining your production processes, solving problems quickly, and implementing consistent progress.
Define Necessary Processes — and Standardize Them
Before you start promoting quality on the production floor, evaluate your current processes — how workers complete their jobs, and whether your manufacturing equipment is appropriate for the tasks workers need to do each day. Are any of your machine parts defective, or unnecessary? Are important project steps skipped, in an attempt to save time?
Your current definition of “quality” — according to the expectations of your customers, and industry standards — should help you to begin standardizing work procedures in terms of content, timing, sequence, and outcome. In other words, you can begin to make sure that everyone does the same job, in the same way, following the same steps. Over time, your definition of “necessary processes” may change, as you implement new machinery and new quality management systems.
Standardizing work procedures, based on what you already know, will engage your employees in understanding the best method for each job. This reduces the chance of quality errors, and enhances the finished product.
Solve Problems Immediately for Preventative Maintenance
Consistent preventative maintenance of equipment is crucial to avoiding downtime — not to mention the significant cost associated with replacing broken down machinery. Build quality testing into each of your processes, and deal with issues instantly; rather than trying to address them at the end of the manufacturing line, when the problem is more expensive to fix.
By replacing worn components when they begin to break, and conducting regular inspections to ensure equipment is functioning at the highest efficiency; you will significantly reduce your chances of falling victim to poor quality.
If you can implement automated testing, do so. When something goes wrong, take it as an opportunity to evaluate the machinery and processes, and aim to eliminate the root cause of the issue.
Remember, even a lack of cleanliness can lead to problems over time — particularly in a production environment, where raw materials leave residue on the machinery. This residue requires regular clearing to avoid breakdowns; just as damaged parts need replacing, and faulty processes need fixing. Don’t wait until a problem becomes too big to solve.
Make Quality a Team Effort
In a huge production factory, it’s unlikely that quality will be sustainably improved by just a few individuals. Make sure every member of your team embraces your quality management measures. You can even bring your team members together in meetings to ask them for input on quality improvement methods. Remember, a variety of perspectives leads to a wide range of solutions to each potential problem.
What’s more, if you use team-based thinking to create a culture of quality, you open the production floor up to constant improvement. You may even collect feedback from certain valued customers, business partners, or suppliers, regarding problems with quality in an existing product. Include this feedback in your team discussions. The more you listen — to your consumer base, your suppliers, and your employees — the more your product will improve.
Implement Changes Gradually
Inefficiencies within processes, or abnormalities in parts, can exist on any production floor. Creating a culture of quality, and ensuring that your team knows the value of their work, will help to ensure mistakes are consistently fixed, and your product is always improving.
Just remember that when you’re implementing large changes into your production processes, it’s wise to do so gradually; by changing one aspect of your procedure at a time. Rapid changes can be difficult for employees to embrace, and may even slow down production — particularly if they involve learning how to use new equipment, or services. Each change should come with the appropriate training, and give your team plenty of time to adapt.
While people often think laser cutting is a new, modern technology — it isn’t necessarily a new concept. In fact, the use of lasers in manufacturing began with the ideas of physicist Max Planck in 1900, when he published his findings regarding the connection between radiation frequency and energy. These findings inspired Albert Einstein’s theories on the concept of stimulated emission, and the principle of harnessing the energy produced by light.
Although Einstein published his ideas in 1917, it wasn’t until much later — in the late 1940’s — that his theories came to life, through the innovations of engineers searching for ways to harness the energy of the “photoelectric effect.” From these first explorations into the world of light and lasers, emerged the first working laser, created by Theodore H Maiman in 1960.
Let’s take a look at how the laser arrived on the manufacturing floor, and how it has affected modern production.
What is Laser Cutting?
Material cutting is one of the most crucial steps in completing a project in manufacturing, or fabrication. The need for accuracy, speed, and efficiency is what prompted the development of laser technology for the industry.
Lasers are high-powered beams of light that can cut through various materials. Today, these machines are generally controlled by computers, and used to melt, vaporize, or burn through components according to a pre-set path, or set of instructions. Once little more than science fiction, laser cutting has proven to be one of the most versatile inventions of the modern world.
History of Laser Cutting
The first laser designed for the purpose of production was introduced by Western Electric in 1965. A leader in the manufacturing and electrical engineering spaces, this company has been a trailblazer in the industry for years, contributing to advanced forms of production. Western Electric began using lasers as a way of drilling holes into diamond dies in 1965, and the technology took off from there.
By May of 1967 (just two years later), a German scientist named Peter Houldcroft had begun developing his own laser-cutting nozzle. This nozzle used a CO2 laser beam and oxygen assist-gas to experiment with industrial cutting. Thanks to these experiments, Houldcroft became the first person to use laser cutting to cut through a 1mm steel sheet. Western Electric quickly jumped on these advancements, making improvements to Houldcroft’s technology — soon enough, lasers were being sold to companies for industrial applications.
In 1969, the Boeing company released a paper discussing the possibilities of using laser cutting on harder materials — such as ceramic and titanium. The paper suggested that, with significant development, laser cutting could become an effective tool for industrial cutting. This groundbreaking paper prompted many companies to begin evaluating the possibilities of laser cutting.
As techniques advanced during the 1990’s, new possibilities emerged in the technique of laser sintering, and the first SteroLithography Apparatus, which allowed companies to create quick prototypes for future technology. By the time the millennium arrived, there were numerous techniques and methods available, raising the standards in laser cutting.
Laser Cutting as We Know It Today
At the beginning of the century, many industries worried that laser systems didn’t have the precision required for complicated designs — those issues are now a thing of the past.
Today’s laser cutting technologies are often integrated with computer-based programming systems, allowing for complete control when cutting various materials. Due to these precise solutions, lasers can now create various shapes and components without distortion, making them ideal for a number of modern industries. Thanks to its non-contact technology, laser machining is a valuable tool in the processing and manufacturing industries. Through its evolution, laser technology has allowed the world of manufacturing to achieve a level of speed and accuracy that Einstein himself may not have imagined — and with engineers constantly working on advancements, who knows where we’ll end up next.
Abrasives make up one of the most important components in the waterjet cutting process. While a pure waterjet (without abrasives) can cut softer materials like foam and rubber, adding an abrasive substance enhances the jet’s cutting capability — to the point where you can cut glass, steel, and a variety of other components. As you might imagine, the type of abrasive used is extremely important in determining the machining outcome.
Professionals have tested various synthetic and natural materials for use in waterjet cutting, and the prominent choice for the industry is garnet. A garnet abrasive offers a reliable and rigid substance that forms sharp edges when fractured — providing superior cutting ability. Garnet offers the correct combination of durability, density, and particle shape to maximize the cutting capabilities of most common waterjets. On top of that, garnet is also mostly chemically inert — meaning it won’t react poorly with materials you’re cutting.
The Best Option for the Best Price
Although it’s possible to synthetically create garnet, for the purpose of waterjet cutting, the substance is found naturally in the earth; extracted from underground mines, and seashore locations. In its ideal form, the mineral looks similar to a ruby — although it’s much less costly. Processing the mineral for use in waterjet fabrication may include crushing it to a specific size, washing it, or simply screening it for a specific “mesh.”
On the MOHS scale — often used to determine the hardness and durability of minerals — diamond earns a level of 10 (the hardest substance known), while garnet usually falls around the 7.5 to 8.5 range. Though there are stronger minerals available, garnet generally offers the best level of hardness, for the most reasonable price.
As an abrasive substance, here’s what garnet has to offer:
- Significant hardness. Garnet can generally last a long time before needing to be replaced, making it a cost-effective abrasive.
- Options for recycling. In some cases, garnet can be recycled, depending on your chosen grit size.
- Environmentally friendly cutting and cleaning. Garnet is frequently used in blast cleaning next to bodies of water, thanks to its lack of chemical input.
Choosing the Correct Garnet
Not all garnet is equal when it comes to cutting. Some garnet solutions are far more productive than others — even though each mineral offers a similar chemical makeup.
On average, abrasive accounts for about 70% of the operating costs associated with waterjet machining. As such, the garnet you choose for any particular project will have a significant impact on the success, and economic impact, of your operations.
Garnet comes in a range of grit sizes, designed to provide different results; such as a smooth or rough finish, depending on the hardness of the machining material. In most circumstances, companies need to use finer grits for processes that demand higher edge quality, while larger grits are most effective in projects that require faster cutting.
Most of the time, when companies purchase garnet for waterjet machining, they receive the substance in a sand-type form, after it’s been run through a screen to obtain the exact sizing required. Garnets come in a range of “mesh” sizes, and companies generally choose a mesh size based on the material they’re cutting. Mesh sizes generally range from between 50 to 200, indicating the size of the garnet abrasive in “microns.”
Most fabricators that process a wide range of materials choose garnet mesh sizes that work on both thick and thin materials — typically 80 mesh. Specialist organizations that cut thicker materials (like granite or steel) might select a coarser 60 mesh, while companies that cut plastic or aluminum might stick to 120 mesh.
Using Garnet for Abrasive Waterjet Cutting
Standing fairly close to diamond on the hardness scale, and more affordable than similar minerals, garnet stands out as the top choice for most abrasive waterjet projects. Some garnet is better for cutting than others depending on its shape, hardness, sharpness, and purity; yet across the board, its durability, sharp edges, and low chemical input make it ideal for working with almost any material. Although other abrasives are available in certain circumstances, most organizations agree that garnet offers the best results, for the best price.