Regardless, the abrasive waterjet has evolved from being a piece of specialty equipment for fabricators to become a new, general-purpose tool in machine shops and manufacturing facilities around the world. Optimizing the tool path for acceleration and deceleration to control the stream while its in the material and utilizing taper compensation to get a high precision cut in a quicker time frame have each contributed to more efficient cutting at any pressure. [citation needed], While cutting with water is possible for soft materials, the addition of an abrasive turned the waterjet into a modern machining tool for all materials. [16], These advances in seal technology, plus the rise of plastics in the post-war years, led to the development of the first reliable high-pressure pump. Acrylic and other plastics are excellent candidates for waterjet cutting thanks to the absence of heat transference, but they do tend to have some chipping or cracking issues when piercing. Much like sandpaper, finer surface finishes require higher, more fine-grained mesh sizes. The effects of additional horsepower also depend on the material being cut. [3] These early applications were at low pressure and restricted to soft materials like paper. Thats according to a 2018 paper by Dr. Axel Henning, Pete Miles, and Ernst Schubert titled Effects of Particle Fragmentation on Performance of the Abrasive Waterjet, presented at the International Conference on Water Jetting, in which the authors studied how cutting performance related to abrasive particle size (see Figure 3). With recent advances in control and motion technology, 5-axis water jet cutting (abrasive and pure) has become a reality. [40] The process is the same for abrasive waterjets until the water reaches the nozzle. Proper waterjet cutting pressure comes from a combination of pump horsepower and nozzle and orifice diameter. Just as increasing wattage increases CO2 laser cutting productivity, increasing pressure significantly improves waterjet productivity, and manufacturers quickly discovered how a 94,000 psi HyperPressure pump dramatically improved productivity when compared to other pumps that operate at approximately 60,000 psi. Commercial water jet cutting systems are available from manufacturers all over the world, in a range of sizes, and with water pumps capable of a range of pressures. For example, the abrasive consumption of a 60,000 psi pump running at 50 hp is the same as a HyperPressure 87,000 psi pump running at 100 hp. 2022 FMA Communications, Inc. All rights reserved. This means the garnet use the main cost driver is cut in half, making the HyperPressure system twice as efficient as the lower pressure pump. Non-abrasive cuts are normally 0.007to 0.013in (0.180.33mm), but can be as small as 0.003 inches (0.076mm), which is approximately that of a human hair. As such, 5-axis cutting opens up a wide range of applications that can be machined on a water jet cutting machine. Abrasives cut only when they successfully reach the material. nozzle orifice at 60 KSI is constrained to a 0.010-in. HYPERPRESSURE VS. NORMAL PRESSURE A critical development was creating a durable mixing tube that could withstand the power of the high-pressure AWJ, and it was Boride Products (now Kennametal) development of their ROCTEC line of ceramic tungsten carbide composite tubes that significantly increased the operational life of the AWJ nozzle. Waste water usually is clean enough to filter and dispose of down a drain. This has the effect that, in contrast to AWIJ, the jet consists of only two components (water - abrasive). There will also be a clear split in systems that are designed for higher productivity and lower productivity, and pressure will play a significant part in that split. Later on the abrasive waterjet entered the scene and began being used for cutting hard materials, including metals, stone, composites, glass, and ceramics. Finding the best combination of horsepower and pressure for a given machine is like telling you the best way to drive your car. These advantages allow manufacturers to quickly produce small or large batches of parts, even for their toughest projects. 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As pressure goes up, the speed of the stream increases. The March 1984 issue of the Mechanical Engineering magazine showed more details and materials cut with AWJ such as titanium, aluminium, glass, and stone. Higher pressure also enables greater cutting detail due to the smaller stream diameter. Pressures have risen steadily throughout the history of waterjet technology. nozzles, a mesh of 120 or higher is optimal. Both play an important role in optimizing waterjet processes, but the relative importance of horsepower and pressure depends entirely on your waterjet application and the condition of the waterjet machine itself. At higher pressures, however, the direct relationship between PSI and cutting speed begins to break down. Hydraulic intensifier pumps can deliver exceptionally high pressures at the cost of an energy-intensive hydraulic system. As long as these materials form the foundation of all abrasive waterjet cutting, horsepower and pressure will play major roles. The interaction of the water jet in the mixing chamber with the air inside creates negative pressure, the water jet entrains air particles. AWSJ cutting, in contrast to the AWIJ cutting process described below, can also be used for mobile cutting applications and cutting under water, in addition to machining demanding materials. High-pressure systems were further shaped by the aviation, automotive, and oil industries. Once the stream exits the orifice, its all about velocity. This means the abrasive speed is governed by the water speed. Its also not practical for applications where actual cut speed and cost per part is a small portion of the total cost to produce the part. Pressure has increased every decade since, moving to 55,000 psi by the end of the 1980s and reaching the current standard of 60,000 psi in the mid-1990s. Meatcutting using waterjet technology eliminates the risk of cross contamination since the contact medium is discarded. Today, there are two different types of Abrasive Waterjets: The Abrasive Water Suspension Jet (AWSJ) - often called Slurry Jet or Water Abrasive Suspension (WAS) jet - is a specific type of abrasive water jet, which is used for waterjet cutting. These advancements contribute to more efficient cutting at any pressure and are a must on any waterjet system, but increasing pressure still yields additional productivity gains. Passing through a small-diameter orifice, the water forms a coherent jet of water that then passes through a venturi nozzle, where a metered amount of granular abrasive is drawn into the water stream. Waterjet cutting is used in various industries, including mining and aerospace, for cutting, shaping, and reaming.[2]. It is also perfect for applications where precision parts are required, since the 33 percent smaller diameter stream enables more intricate inside corner cutting down to a 0.015 in radius. For example, 4 inches (100mm) thick aluminium Q5 would be 0.72in/min (18mm/min) and Q1 would be 4.2in/min (110mm/min), 5.8times faster.[54]. Eighty-mesh garnet is most universal between nozzle sizes, whereas 50-mesh garnet is much coarser and is typically used with larger-diameter orifices such as 0.022 or 0.020 in. The AWIJ[32] is generated by a water jet that passes through a mixing chamber (a cavity) after exiting the water nozzle and enters a focusing tube at the exit of the mixing chamber. [26] The abrasive grains become faster with the WASS than with the WAIS for the same hydraulic power of the system. Figure 1. [43] Sharp corners, bevels, pierce holes, and shapes with minimal inner radii are all possible. In waterjet cutting technology, a jet is considered more efficient if it cuts faster at a lower cost for the input power. There are some minor drawbacks to HyperPressure systems. The garnet abrasive is a non-toxic material that can be mostly recycled for repeated use; otherwise, it can usually be disposed of in a landfill. Notice here how jet speeds have increased over time. Abrasive Water Suspension Jet (AWSJ) cutting, Abrasive Water Injector Jet (AWIJ) cutting. There are six main process characteristics to water jet cutting: Edge quality for water jet cut parts is defined with the quality numbers Q1 through Q5. In the nozzle, the water is focused into a thin beam by a jewel orifice. Chadwick, Ray F Chadwick, Michael C Kurko, and Joseph A Corriveau. Used to cut honeycomb laminate for the Mach 3 North American XB-70 Valkyrie, this cutting method resulted in delaminating at high speed, requiring changes to the manufacturing process. In 1987, Ingersoll-Rand Waterjet Systems offered a 5-axis pure-water waterjet cutting system called the Robotic Waterjet System. In abrasive waterjet cutting systems, however, the abrasive does the cutting, not the water. Dr. Mohamed Hashish, the inventor of the abrasive waterjet in 1979, has discussed the correlation between water velocity to pressure in numerous technical papers he has authored over the decades. Produces a taper of less than 1degree on most cuts, which can be reduced or eliminated entirely by slowing down the cut process or tilting the jet. The correlation between water velocity to pressure. The largest waterjet manufacturer, Flow International (a spinoff of Flow Industries), recognized the benefits of that system and licensed the OMAX software, with the result that the vast majority of waterjet cutting machines worldwide are simple to use, fast, and accurate. Glass behaves similarly in this regard. That being said, some combinations of horsepower and pressure tend to work under ideal conditions and with specific orifice/nozzle sizes. When Ultrahigh-Pressure (UHP) waterjets first came on the market, pressures were in the 36,000 psi range. Most machines accomplish this by first running the water through a high pressure pump. It has a short ROI due to its ability to produce parts cheaper and faster with less labor costs. [45], Due to its relatively narrow kerf, water jet cutting can reduce the amount of scrap material produced, by allowing uncut parts to be nested more closely together than traditional cutting methods. Walker, The Application of High Speed Liquid Jets to Cutting. [23] By January 1989, that system was being run 24 hours a day producing titanium parts for the B-1B largely at Rockwell's North American Aviation facility in Newark, Ohio. [34] Creating motion control systems to incorporate those variables became a major innovation for leading waterjet manufacturers in the early 1990s, with John Olsen of OMAX Corporation developing systems to precisely position the waterjet nozzle[35] while accurately specifying the speed at every point along the path,[36] and also utilizing common PCs as a controller. Finish and accuracy also improve because the higher PSI focuses the particles at a single point. However, the only way to find the best balance between horsepower and pressure is to perform plenty of experimentation and have a close working relationship with the waterjet OEMs applications experts. As waterjet cutting moved into traditional manufacturing shops, controlling the cutter reliably and accurately was essential. For a given pump power, any increase in pressure must be matched by a proportional decrease in volume flow rate. In a direct-drive waterjet pump, the horsepower comes from the crank case, pictured here. Aircraft manufacturers such as Boeing developed seals for hydraulically boosted control systems in the 1940s,[14] while automotive designers followed similar research for hydraulic suspension systems. For most shops looking to increase cutting speed on an existing machine, adding a higher-horsepower pump will provide the greatest advantage. Intervals between maintenance can be slightly shorter, but that is mitigated by quick maintenance techniques and simple-to-handle seal cartridges in the newer pumps. A good starting point is 20-50 HP and 60 KSI of pressure and a jewel size of 0.011 in. Regardless, the basic principles behind waterjet cutting havent changed. Power is proportional to pressure times volume flow rate (P = kp V). Intensifier pumps were considered easier and cheaper to maintain, especially at high pressures, while direct-drive systems offered higher energy efficiency. Foams require a different approach altogether, because the waterjet process does not use abrasives. For most standard metals, including aluminum, steel, brass, and titanium, the correct cutting conditions will differ depending on whether the material is thick or thin. Since the inception of waterjet technology nearly 50 years ago, there has been an ongoing argument concerning what combination of pressure and power results in optimal cutting performance. The abrasive is pulled into the cutting head from very low velocity via a venturi effect (a way of creating suction) and then accelerated down the mixing tube by the supersonic water, as shown here. After contact with the abrasive material in the mixing chamber with the water jet, the individual abrasive grains are accelerated and entrained in the direction of the focusing tube. If youve ever investigated purchasing a waterjet system, youve probably been hit with an onslaught of marketing and sales data showing the benefits of each. Sullivan will be based out of the companys headquarters in Norwalk, Conn. beginning August 1. Both vehicles will get you from point A to point B; the question really comes down to how nice the ride is. Mohamed Hashish was awarded a patent on forming AWJ in 1987. Others have advocated direct-drive systems that use a mechanical crankshaft pump (see Figure 1). While using high-pressure water for erosion dates back as far as the mid-1800s with hydraulic mining, it was not until the 1930s that narrow jets of water started to appear as an industrial cutting device. Easily access valuable industry resources now with full access to the digital edition of The Tube & Pipe Journal. To frame the discussion, lets remove the intensifier versus direct-drive pumps argument. You can expect that trend to continue, with a likely 25 percent to 30 percent increase in pump pressures in the next five to ten years. What does all this really mean? Where the normal axes on a water jet are named Y (back/forth), X (left/right) and Z (up/down), a 5-axis system will typically add an A axis (angle from perpendicular) and C axis (rotation around the Z-axis). IMTS will be held September 12-17, 2022, in Chicago. Because of the angles that can be cut, part programs may need to have additional cuts to free the part from the sheet. [13] By the turn of the century, high-pressure reliability improved, with locomotive research leading to a sixfold increase in boiler pressure, some reaching 1,600psi (11MPa). But if the abrasive flow rate, nozzle/orifice diameter, and horsepower at the nozzle are all the same, an intensifier pump and a direct-drive pump will cut at the same speed through most common materials and thicknesses. A 5-axis head can cut parts where the Z-axis is also moving along with all the other axes. Maintenance is easier since the new pump is designed for fast, foolproof maintenance with a special high-speed pressure loading tool provided with the pump. orifice at 90 KSI. Pressure equals productivity and efficiency because of jet velocity. The nozzle/orifice combination assists in pressurizing the water as it is squeezed from high-pressure piping through an opening. The move to higher pressure has improved the productivity of waterjet cutting systems, but the increase in jet velocity is actually the driving force behind these dramatic gains in efficiency. Even as the technology changes, water and garnet largely remain the same. The only way to make a waterjet stream go faster is to raise pressure but not through increasing horsepower. Leach and G.L. For smaller nozzles used for high-precision applications, such as 0.014- or 0.010-in. [48] Examples of materials that cannot be cut with a water jet are tempered glass and diamonds. orifice, a 50-HP intensifier pump running at 60,000 PSI generally will output 1 gallon per minute (GPM). Olsen, John H., George H. Hurlburt, and Louis E. Kapcsandy. The global automation solutions leader invests in US manufacturing with plans of a second expansion in three years to meet growing need. [7] Research by S.J. | Privacy Policy. Water jets are capable of attaining accuracy down to 0.005 inches (0.13mm) and repeatability down to 0.001 inches (0.025mm). The invention of Marlex by Robert Banks and John Paul Hogan of the Phillips Petroleum Company required a catalyst to be injected into the polyethylene. Easily access valuable industry resources now with full access to the digital edition of The FABRICATOR. Safety lessons from a welding equipment manufacturer, In The Workshop, Ep. However, before the use of HyperPressure pumps became common, many other alternatives to improve productivity were attempted: Other methods that have been employed include optimizing the tool path for acceleration and deceleration to control the stream while its in the material and utilizing taper compensation to get a high precision cut in a quicker time frame. This full 5-axis cutting could be used for cutting contours on various surfaces of formed parts. Waterjet technology evolved in the post-war era as researchers around the world searched for new methods of efficient cutting systems. Typical distance is .125in (3.2mm). This can be useful for applications like weld preparation where a bevel angle needs to be cut on all sides of a part that will later be welded, or for taper compensation purposes where the kerf angle is transferred to the waste material thus eliminating the taper commonly found on water jet-cut parts. [15] Higher pressures in hydraulic systems in the oil industry also led to the development of advanced seals and packing to prevent leaks. Nozzle size is not the only factor that determines the ideal mesh size for a given application. Pressure is determined by the volume of water being pushed through a nozzle orifice by a pump (see Figure 2). Copyright 2022 Alliance Communications, Inc. All Rights Reserved. Higher horsepower will definitely speed up machining 3-in.-thick aluminum, but the effects will be negligible when machining shim stock using a 0.010-in. In 2004, the HyperJet pump was introduced into standard manufacturing environments with a rating of 94,000 psi a breakthrough that began the era of HyperPressure cutting with waterjets.
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