Advances in laser technology offer shops more powerful, cost-efficient ways to boost cutting efficiencies
By Patrick Waurzyniak
Faster, more powerful laser cutting technologies are enabling wider application of lasers beyond more traditional fabrication job shops. With improved laser-cutting hardware, software, controls, and automation options, today's laser users are cutting metal more quickly and efficiently to meet the exacting standards demanded by today's manufacturers.
With improvements in lasers, many job shops are now combining the laser equipment previously found more in fabrication shops with the traditional metalcutting machines that dominate most chipmaking operations. "When you go into job shops, they're either chip or fab; very few have both technologies," notes James Rogowski, 2-D product manager, Trumpf Inc. (Farmington, CT). "We're starting to see more job shops—whether they're chip or fab—make the leap to the different technology and have both available."
More manufacturers are using high-power lasers for roughing operations that employ flatsheet lasers to rough out or remove excess material from high-tensile-strength materials, Rogowski notes. As laser technologies' efficiencies improve, lasers represent an attractive cost-effective alternative to conventional carbide drills and end mills for roughing.
"The higher power, of course, is probably the first asset that is allowing us to get a foot in the door in a chip shop—the higher power gives us the higher capacity," Rogowski says. "Now we have a 6-kW machine that can cut up to 1" [25.4-mm] thick stainless steel. But also, as we create these higher-power machines, we're making them operate at a lower cost per hour, and thus incurring less cost per part.
"In the past, for example, if you had a piece of 1" stainless steel, first of all you could not rough that out on a laser, because a laser didn't have the capacity to cut 1" stainless steel. Secondly, if you did, the cost for that part on a laser was greater than it is today. We're making a machine now that can cut the material and has very few consumables. It runs at a lower cost per hour than a chip machine, and can cut through those materials more quickly than an end mill can."
Laser cutting systems can save chip shops significant amounts of money on consumables related to maintenance and coolant, but also lasers are cheaper simply by not using expensive tooling. "Of course, the most expensive side of a chip machine for consumables is the actual tool that you're using," he adds. "That is a consumable, and end mills can be very expensive—a 1/2" [13-mm] carbide end mill with coating can be $50–$60."
Last October, Trumpf introduced a new 6-kW CO2 laser resonator, the TruFlow 6000, for flat-sheet laser cutting. It's now available on the company's high-speed TruLaser 5030 system, which was initially introduced in North America with a 5-kW resonator. Equipped with linear drives, the high-power resonator increases cutting speeds up to 29% while improving quality and efficiency. The TruFlow 6000 resonator cuts effectively at speeds of up to 1900 ipm (48 m/min) when processing thin sheets at high speeds. The system is said to be capable of cutting material as thick as 1" mild steel and stainless steel, and 5/8" (15.9-mm) aluminum.
"Certainly the tolerances and finishes have improved in lasers as well," Rogowski adds. "As lasers get higher power, and as we develop new techniques for cutting, the finishes become better and better. Now, you don't have the very tight tolerances that you can get with a chip machine. But once again, if you had to rough 25 parts out of a sheet of stainless steel, it can be done faster and cheaper on a laser machine than it can be done on a chip machine."
Improved tolerances for laser-cut parts have also expanded the applications considered suitable for laser technologies. "On the machine side, what we observe is chip manufacturers are seeing some more realistic tolerances these days. We have engineers that are really studying end products, whereas opposed to maybe 20 to 30 years ago, they were just assigning tolerances to parts, sometimes without any rhyme or reason. Now we're starting to see parts that, if you need a certain tolerance on them, then certainly you have to cut them on a chip machine or an EDM machine, something that can hold those extremely tight tolerances. Anything ±0.002" [0.0508 mm], you'd have to machine on a machining center, and anything greater than that, we consider running on a laser machine.
"We're starting to see more and more chip guys looking at lasers, for example, with quarter-inch mild steel or quarter-inch stainless steel, specifically the materials with higher-tensile strengths, because those will eat up the consumables on a chip machine. With those higher-tensile strengths, people from the chip side will start to consider more and more using lasers to rough those parts out and, where they can, finish them."
Another higher-tensile strength material is the Armox material used in armor plating, Rogowski adds. The Armox material, from SSAB Oxelösund AB (Sweden), is used in the security industry for armored vehicle protection. "That is extremely high-tensile-strength material that a lot of our job shops and even OEMs are using in Humvees to protect our troops. These higher-tensile strengths are very difficult to machine, or maybe not so difficult, but very costly, in comparison to using a laser."
Automation options, tapping tools, and new software are among the many productivity-enhancing features included in the fixed-beam laser cutting systems offered by Mazak Optonics Corp. (Schaumburg, IL), a subsidiary of Yamazaki Mazak Corp. (Oguchi, Japan). Mazak Optonics has recently released four new laser cutting systems including the HyperGear with FMS automation and OptoPath sorting system, the HTX, the STX Champion, and the FabriGear with Tapping Tools, plus an updated software solution, e-Soft, designed to increase customers' productivity.
Automating the laser-cutting process, Mazak Optonics offers customers several levels of automation, from pallet shuttles to the company's Flexible Manufacturing System (FMS), that help optimize machine utilization, notes Lou Derango, Mazak Optonics 2-D product manager. "One of the things we look for in automation is that, although we get better machine utilization, are we also getting better operator utilization? As everybody knows, labor rates and material costs continue to rise, so we need to offset that to keep our margins. We need to use our equipment and labor better.
"We took a look at our machine and labor utilization, and when we use the machine and labor more efficiently, we're adding value-added time and subtracting non-value added time," Derango says. "We've done that again in tool change. When you go from one material thickness to the next material thickness, you need to have a different setup, a different way to cut thick or thin material. If we oversize our nozzle, we're expending a lot more gas than necessary; in different applications, we could be expending $7 an hour or better just in gas because we didn't optimize the setup."
With the Mazak Optonics HyperGear 2-D laser system, users get a torch and nozzle changer that automatically sets focus lens position, nozzle to material distance, and beam adjustments. Nozzle inspections are performed with a CCD camera, and the automated nozzle changers recondition, change, and recalibrate nozzles, all under the guidance of the software system. Available as either a 2.5-kW or 4.0-kW laser cutting system, the HyperGear system processes up to 1" mild steel and comes with a standard 5 x 10' (1.5 x 3-m) bed and the next-generation Mazatrol Preview 640 PC Control and Linear Drives, allowing the system to cut at speeds with 3g acceleration while maintaining dimensional accuracy and cutting corners with precision.
Adding tapping tools, the Mazak Optonics FabriGear line of 3-D lasers adds an automatic tapping system that enables the system to tap threads on a variety of material types including round, square, rectangular, and triangular pipes, as well as C, L, H, and I beams. Holding six different taps, the system uses compressed air to tap holes under 1/2" in diam. On the HyperGear, the system can feature a toolchanger with as many as 20 stations. "Taps get broken after so many uses, so we have tap breakage detection on the machine—if the tap is broken, the system detects it, gets a new one, and continues to tap," Derango notes. "So there's a need for multiple stations for taps and torches in a large toolchanger.
"We're optimizing everything we can," he adds. "In addition to the fixed-beam delivery system to the materials and the consumables that we're using, and how the operator interfaces with the machine, we're adding automation. Across the board, we're looking at our value-added and non-value-added time, optimizing our materials used and our labor."
Lights-out laser cutting also is possible with the company's e-Tower software, which helps users schedule jobs to run untended overnight or over weekends. "When we combine our software like our e-Tower with a load/unload device, it becomes more of a management system," Derango states. "It manages several different programs. We can take the operator out of the picture by utilizing our e-Tower software as a scheduler. You can set up a long list of queues, it switches programs and loads sheets.
"We have a lot of customers that do untended operation," he adds. "This software allows them to further take the operator out of their costing for making a part, and they're better able to compete. We have a customer who does unattended operations regularly; on the weekend, he schedules an operator basically on call, and on the weekend he comes into the shop once, switches on the system, and leaves. They use Web cameras to take a look at what's going on at the machine in real-time and log on through the Windows remote desktop to access the system."
Automation equipment remains a key requirement for customers with more than half of the laser cutting systems from MC Machinery Systems Inc./Mitsubishi Laser (Wood Dale, IL) ordered with some kind of automation, notes Jeff Hahn, Mitsubishi national product manager. "Whether you buy it with the automation or standalone, we have a very modular automation scheme," Hahn says. "Automation is the biggest trend leading the market right now. With automation, you must have very high reliability if you're in a 24/7 environment."
With Mitsubishi's automation offerings, customers get options ranging from units handling 22,000 lb (9900 kg) of material to tower systems featuring eight to 20 shelves that hold 6000 lb (2700 kg) per shelf. Lights-out cutting is enabled with the Ncell automation software for line control, Hahn adds, which is supplied by Mitsubishi's partner Ncell Systems Inc. (Minnetonka, MN).
"That's what a lot people are doing with our equipment, especially on weekends," Hahn notes. "The software's very sophisticated, and if there's any issue, it'll give you an alert. It's being used in all industries, but our mainstay has always been the job-shop environment. Because of our reliability, more and more OEMs are giving us a chance to prove our equipment, but the job-shop market has been the biggest for us."
With its patented X-Flow cross-flow resonator, Mitsubishi offers a different resonator type than competitors, Hahn notes. "We're the only cross-flow laser on the market," he says. "Just about all the other laser manufacturers are fast-axial flow. What our resonator offers is lower cost of ownership. Inside the resonator, there are no glass tubes, and there is no turbine blower. What makes ours significant is that I can turn it on in 45 sec, and turn it off in two minutes, so it really aligns itself with JIT operation."
At the high end, Mitsubishi offers its LVPlus model with a 4-kW resonator laser and the company's Diamond-Path Technology, which maintains consistent beam quality by using a constant-beam-length system that the company says enables cutting stability at speeds up to 1150 ipm (29.2 m/min) across all processing areas. "Mitsubishi builds the resonator, machine tool, controller, servos, and the amps," Hahn notes. "On our LVPlus, we have the Diamond-Path, a fixed-beam-length system. Early on, when flying optics first came out, the one flaw in them was they would cut differently near to the resonator than they would farther from the resonator. With Diamond-Path, you have the same cutting ability from one end of the table to the other end, and we have adaptive optics, which change the beam size according to the application."
High-speed laser cutting is also offered by Prima North America Inc. (Chicopee, MA), a subsidiary of Prima Industrie S.p.A. (Torino, Italy), with its new high-performance Syncrono 2-D laser and new CV5000 laser resonator.
Prima's Syncrono laser features a fully automated material-handling system, and it offers a patented laser head designed with two additional small, linear-motor-driven parallel kinematics axes on the moving gantry. The system is said to cut at high acceleration of up to 6g, allowing the laser to cut more than 1000 holes per min. Its automated material-handling system consists of either a 10 or 15-shelf storage pallet loading/unloading unit, automatic arm with pick-up device and suction-cup loading, a double-sheet thickness control device, a sheetmetal separation unit, controller, and standard protection barriers.
This article was first published in the August 2007 edition of Manufacturing Engineering magazine.