Taking Off After New Applications
Waterjet cuts materials fast, sheds its mysteries faster
The advantages of abrasive waterjet machining are no longer a mystery to the everyday shop user, and haven’t been for some time. Steel, stainless, titaninum, composites, and high-temperature alloys and exotics including Inconel, Waspaloy, and Hastelloy, as well as a wide array of nonmetals, are being routinely cut. Materials, especially for sensitive applications, can be cut without heat-affected zones (HAZ) and heat deformation. Complex 3-D shapes can be machined through the use of sophisticated programming and 3-D machining heads. The environmental impact of waterjet is negligible. There’s no contamination from airborne dust particles, smoke, fumes, other irritants, or even deafening noise to deal with. Garnet abrasives can be recycled for use or readily disposed of.
Trends in waterjet technology are expanding applications with larger machines, higher pressure pump technology, including multiple cutting heads, and increased ability to cut complex 3-D shapes. Waterjet machine models cover a wide range of applications. They have the versatility to satisfy rapidly changing job-shop requirements or run continuously in production environments. Technology is pushing the envelope for running through multiple shifts with extended uptime and reduced concern about unexpected maintenance downtime.
According to John Olsen, vice president operations, OMAX Corp. (Kent, WA), the market for larger machines with X axis to 40' (12 m) is something that wasn’t envisioned in the early days of waterjet technology. “Initially, we thought of waterjet as something more like a shop mill, a Bridgeport for the shop. Today, nothing could be further from the truth. Our smaller machines are cantilever-arm style that can be accessed like a drill press. All of our large machines are bridge-style machines. In fact, we’ve recently introduced dual-bridge machines that behave like two totally independent machines on one table with the advantage of having two smaller machines. But when the job calls for a really large part, you can run one bridge and do the big part. We have one right now that is 10 × 40' (3 × 12 m). Applications for these larger machines include rail car components, aerospace structural workpieces, and steel service centers that benefit from nesting and cutting parts efficiently from large plate. The service centers get good material savings, nice clean edges without any slag to remove, or hardened edges that can tear up mill work.”
An area of critical importance is pump technology. “Because of improvements in high-pressure seals and cylinder components, we can run 60 ksi [4137-bar] pumps a thousand hours before routine maintenance compared with several hundred hours previously,” says Olsen. At Fabtech, OMAX will demonstrate its premium OMAX 80X JetMachining Center equipped with an EnduroMax pump and Tilt-A-Jet cutting head, as well as its cost-efficient Maxiem 1530 JetCutting Center with a multiaxis A-Jet accessory and an efficient direct-drive pump.
Like all OMAX JetMachining Centers, the 80X has the ability to cut a wide variety of materials, including ceramics, composites, plastic, glass, and stone, as well as metals such as aluminum, tool steel, stainless, mild steel, and titanium with an accuracy of motion up to ±0.003" (0.076 mm). The 80X features an X-Y travel of 165 × 80" (4191 × 2032 mm), and is equipped with OMAX Intelli-MAX software, running on the Windows 7 Ultimate operating system. The system can calculate the precision of the velocity of a tool path at over 2000 points per inch, allowing for complete control over the motion of an abrasivejet, and enabling precise, rapid machining.
“Initially, we thought of waterjet as something more like a shop mill, a Bridgeport for the shop. Today, nothing could be further from the truth.”
The 50-hp (37-kW) EnduroMAX pump provides double the operating life of previous pumps, and makes for faster part processing, lower operating costs, and easier maintenance. It maximizes machine uptime with its 1000-hr operating range between required pump rebuilds when run at 55 ksi (3800 bar). However, the pump can also effortlessly run continuously at 60 ksi (4100 bar). The EnduroMAX pump operates at 90% efficiency, as opposed to the 60–70% range of intensifier pumps.
The Maxiem 1530 JetCutting Center is well-suited for fabrication shops, metal service centers, trade schools, job shops, architectural, sign, stone and gasket shops. It will be equipped with a high-pressure direct drive 50 ksi (3447 bar) pump in a 30-hp (22-kW) configuration and an A-Jet multi-axis accessory that cuts beveled edges and angles with an articulated jet. The Maxiem product line’s X-Y cutting travel ranges from 30 × 30" to 160 × 79" (762 × 762 mm to 4064 × 2006 mm).
According to Brian Kent, global product manager, Flow International Corp. (Kent, WA), operating pressures will continue to increase because higher pressure always leads to faster, more efficient cutting. “As this trend continues, pump design and other components will continue to evolve to improve performance. The latest development has been modeling the waterjet stream with the ability to program 3-D parts from a solid model and cut them without the additional taper typical of a waterjet. The direct benefit for the users is that they can now import solid models directly into the software so they can program parts faster and cut more accurately, because the modeling is done with the true solids and they aren’t relying on projections,” Kent explains.
“Combining this capability with Flow’s Dynamic Waterjet XD wrist allows users to cut complex parts free of taper. For the last ten years, it has been possible to cut 2-D parts without taper with Dynamic Waterjet technology, and it has also been possible to cut five-axis parts, but the machine could only do one or the other. Now, Flow’s Dynamic XD combines these two technologies and allows the user to cut complex 3-D parts free of taper,” Kent says.
The newest addition to Flow’s machine models is the Mach 4 line which features modular design that can be expanded up to 14 m in length. The Mach 4, which is a high-end production machine well-suited for aerospace production, is being shown at Fabtech. The Mach 4 will demonstrate the combination of Flow’s HyperJet pump, rated at 94 ksi (6481 bar) and Dynamic Waterjet XD, high-precision flat stock and 3-D cutting technology.
The latest developments from Jet Edge Inc. (St. Michael, MN) can be found in its X-Stream waterjet intensifier pumps. Jet Edge will exhibit its 100-hp (75-kW), 90-ksi (6205-bar) X-Stream xP90-100 waterjet intensifier pump at Fabtech. According to Bradley Schwartz, regional sales manager, X-Stream pumps are capable of producing 90 ksi (6205 bar) and supporting 75 ksi (5171-bar) continuous operating pressure. “The X-Stream pumps produce 50% more pressure than a 60 ksi [4137-bar] intensifier pump, resulting in a 40–50% increase in productivity for cutting many materials. Compared to a 60 ksi [4137-bar] pump, typical operating pressures of 75 ksi [5171-bar] use 30% less water, 30% less power, and up to 50% less abrasive, resulting in a 40% reduction in operating costs. The xP90-100 is capable of producing flow rates of 1.45 gpm and supports up to a 0.017" [0.43-mm] orifice.”
A wide range of electric and diesel waterjet intensifier pumps rated from 30 to 280 hp (22–209 kW) are available. “At lower pressures, 100 hp [75 kW] can push two very large jets,” Schwartz points out. “On our 90 ksi [6205-bar] models, we offer 50 and 100 hp [37, 75 kW]. The end result is flowing less water at higher pressure, higher velocity, and accelerating the garnet abrasive much faster, resulting in higher cutting throughput.”
The list of materials that can be cut by waterjet is really quite extensive. “For NASCAR’s Michael Waltrip Racing, waterjet is cutting 2" (50.8-mm) 4140 parts and saving 20 min per part cutting at higher pressure. Applications range from cutting composites for the downdrafting components on the front of the race car to drivetrain and suspension components, and the hundreds of different parts that go into each car,” says Schwartz.
For cutting complex parts, Jet Edge offers the Mid Rail Gantry Waterjet System that features many sizes ranging from 5 × 5' to 24 × 13' (1.5 × 1.5 m to 7.3 × 4 m). The Mid Rail Gantry model is equipped with one abrasivejet cutting head with the option for adding a second cutting head. Ballscrew-driven for high accuracy, the Mid Rail Gantry uses an industrial PC controller and can be configured so that all three axes are fully programmable.
“An area of critical importance
is pump technology.”
Precision Waterjet Concepts Inc. (Pequot Lakes, MN) has installed a Jet Edge Mid Rail Gantry waterjet cutting system with dual abrasivejet cutting heads with mirroring capabilities. Powered by a 60 ksi (4137-bar), 150-hp (112-kW) Jet Edge iP60-150 waterjet intensifier pump, the Mid Rail Gantry is capable of processing materials up to 8 × 13' (2.4 x 4 m). “We went with a Mid Rail Gantry for our second system, because of the mirroring system and programmable head spacing,” explains Joe Quaal, president.” We cut a lot of extremely large parts and we can save a lot of time and money by mirroring. Fifty percent of the time, we are mirroring. The programmable head spacing also saves up 10–15 min per job on setup time.”
Going outside traditional markets for waterjet technology is not uncommon. Jet Edge Mid Rail Gantry machine technology is being used to cut Insulation for a cryogenic refractory market application, says Schwartz. The material comes in rolls and has to be cut to wrap very long pipe parts. The machine’s large format and ability are able to match the high feed rate required with repetition for cutting the insulation. The machine’s software and controller enable the machine to continue cutting without returning to home position, a definite improvement over the previous controller, says Jet Edge’s Schwartz. “Unique to our control is that when a large piece of material is placed on the table, the sheet is located and rotated for nesting.”
Mitsubishi/MC Machinery Systems Inc. (Wood Dale, IL) with its partner KMT is introducing the latest PRO series pump with cutting pressures now at 100 ksi (6895 bar). “We all see the benefits of going from 60 to 90 ksi [4127–6205 bar], and now reaching 100 ksi, speeds will increase by about 15%,” says Steve Szczesniak, national waterjet product manager. “With greater cutting pressures, higher speeds are achievable, thereby doubling throughput on the machine. Customers are truly seeing this benefit and continue to replace older lower-pressure technology. We even have taken our experience and knowledge from the EDM applications and married them to the waterjet process. For instance, integrating a B axis to index complex parts that would traditionally have needed a five-axis type cut are now being done on waterjets by our customers at lower cost of a complete package. And we still have all of the benefits of a traditional waterjet for the less complicated applications. With our machine design, tighter tolerances are achievable more now than ever before, so waterjet is complementing EDM, milling, and laser even more. With higher cutting pressures, and this is even climbing faster, better surface finishes are achievable so waterjet becomes a viable alternative to conventional processes.”
At Fabtech, the Mitsubishi Waterjet four-axis DX510, which features Intelligent Tapering Control to correct the natural tapering of the cut automatically, will be demonstrated. Through the CNC, the DX510 inclines the waterjet up to ±2° while pointing the jet toward the cutting direction. This process allows for the optimum cutting speed in a contour with accurate wall straightness.
Bystronic Inc. (Elgin, IL) is well known for its high-end waterjet technology designed for automated high-production environments. “In the US, we were focused on the very large, high-end market with a standard machine that could be automated with a power shuttle. Now we are introducing the ByJet Smart, a mid-priced cantilever-style machine targeting job shops, general engineering, waterjet shops, laser shops, and fabricators who want the benefits and advantages of waterjet alternative cutting technology,” explains Brody Fanning, vice president sales.
The ByJet Smart will be introduced to the US market at Fabtech. “Like all of our machines, the ByJet Smart features Swiss precision for 2-D cutting applications, equal to or better than the accuracy of comparable waterjet machines,” says Fanning. Applications that are being targeted for the linear-motor drive machine include traditional metal cutting, as well as straight-waterjet applications cutting foam rubber, gaskets, insulation, and similar nonmetal applications. “The ByJet Smart with one or two cutting heads features a high efficiency, direct-drive pump rated at 55 ksi [3792 bar], with 30% more efficiency and 30% longer duty cycle on its wear components,” says Fanning. The machine can process material thickness of 8" (200 mm) and has a cutting range for flat processing of 120 × 60" (3048 × 1524 mm) with positioning accuracy of ±0.003"/m (±0.08 mm/m) and repeatability of ±0.0009" (±0.025 mm/axis).
“We intend to pursue traditional applications like aluminum cutting. The aerospace industry has always accepted waterjet well, because it’s HAZ free. The ByJet Smart is available in one size: 5 × 10' [1.5 × 3 m]. We continue to offer our larger format machine, the ByJet ClassicL, which is available in 10 × 20' [3 × 6 m] or larger, with the latter more suited to service centers. In any case, in making their decisions, end users need to consider the total cost to produce a part, including machine amortization, performance, the ability to run multiple heads, and, of course, maintenance costs. The cheapest machine won’t necessarily produce the lowest cost per part,” Fanning concludes. ME
This article was first published in the November 2011 edition of Manufacturing Engineering magazine. Click here for PDF.