Advances in technology have changed laser cutting economics
By James R. Koelsch, Contributing Editor
and Jim Destefani, Senior Editor
Many fabricators are making the same discovery about laser cutting that one manufacturer of decorative shelves recently made: justifying the initial investment and operating costs of a laser system is much easier than it was a decade ago. Advances in technology make laser cutting much more versatile and faster. Consequently, today’s laser systems can save significant sums of money, even sometimes when pitted against punch presses.
Such was the case at the manufacturer of shelving units. The company had been producing parts using a punch press followed by tumbling and polishing. Switching to a laser cutting machine from Amada America Inc. (Buena Park, CA) produced the pieces at roughly the same rate but also eliminated secondary processing and punch inventory. It also allowed processing of plastic parts with no additional capital equipment, enabling the user to introduce lines of products containing plastic and pursue customers that prefer this material.
Laser technological advances fall into two major categories: those that improve the quality of the laser beam itself and those that streamline going from drawing to finished parts. Better beams mean better and faster cuts, and easier-to-use machines mean faster changeovers. Not only can one laser head cut a greater number of materials, but also software and hardware often automate those changeovers that are necessary. “Features in the controller accommodate changes in the type and thickness of the material, so you don’t have to change heads,” says Amada laser division manager Ancel Thompson. And when changes are necessary, quick-release nozzles and lens cartridges streamline the task.
Probably the most important development for boosting the productivity of lasers is better beam quality. Generating more powerful beams and throwing them at the cut would do the job in most cases, but the strategy is too expensive to be practical. Both development and operating costs would be too high.
Consequently, builders have poured their resources into delivering the power they need in a different way. They have been refining the beam itself, generating one that resists diverging and stays together longer so they can focus it into tighter spots and create higher energy density.
As the heart of laser cutting, the resonator is key to better beams. Although resonator design has improved across the board, Rick Neff, laser product manager at Cincinnati Inc. (Cincinnati), believes that the type of resonator is crucial to beam quality. For this reason, he prefers a diffusion-cooled resonator. “Its main characteristic is a beam with a very small divergence angle,” he says. “The smaller that angle, the better the beam will focus to a small spot. For instance, a 4000-W, fast-axial-flow resonator would have a typical power density of 13 MW/cm2. A 3300-W, diffusion-cooled resonator set up to cut the same material would have a power density of 37 MW/cm2.”
Consuming less overall power means lower operating costs, and creating greater power density from a less powerful beam means that “the diffusion-cooled resonator is like cutting with a sharper knife, rather than cutting with a stronger arm,” notes Neff. “Some materials, especially thin ones, see great benefit from being cut with a sharper knife.” Others, such as thick steel plate, require the “strength” provided by raw power.
To capitalize on the beam that its resonator generates, Bystronic Inc. (Hauppauge, NY) has developed software and optics that can adjust the diameter and other characteristics of the beam produced by its 5.2-kW CO2 laser cutter for the particular materials that it is cutting. Using data from its material library, the laser’s controller modifies the beam automatically for the particular material and thickness that it is cutting.
“The user simply selects material type and thickness when entering the job’s parameters,” says Michael Zakrzewski, vice president, Metal Processing Systems Div. “The machine then shapes the beam automatically for the material.”
Most manufacturers build and tune their laser cutters to accommodate a large range of materials, but Bystronic claims that optimizing the beam for the raw material can increase feed rates by as much as 30%. “The ability to modify the beam for a variety of materials changes the situation entirely because the laser is now tuned for peak performance on each job,” explains Zakrzewski.
The ability to manipulate the beam to preserve its quality is especially important for specialty machines such as the Alpharex plate cutter from ESAB Welding and Cutting Products (Florence, SC). Maintaining beam quality over the entire cutting area becomes a challenge when the smallest model in the line has a 10′ (3-m) width and can be more than 100′ (30 m) long. The beam can diverge substantially and produce inconsistent results as the head traverses these distances.
To solve this problem along the length, ESAB engineers mounted the resonator on the bridge so it moves to the required X coordinates and eliminates the problem in that direction altogether. For the Y axis, they developed three adaptive-optic lenses that adjust on the fly to prevent beam divergence as the head moves. Based on a position map and material library, the machine’s CNC varies the pressure of the coolant behind the mirrors to adjust their concavity, which in turn controls focus and thus beam divergence.
Faster Drives. Because better beams and higher power mean faster cutting, builders have fitted their machines with drives that keep up with the laser. Linear motors have become quite common on modern laser cutters. Cincinnati Inc., for example, has been using these very fast and responsive drives on its flagship laser systems since 1996. “Linear motors allow for higher productivity, especially if you have lots of small features where you spend a lot of time traversing from one feature to another,” says Neff.
To maintain beam quality on its large Alpharex gantry plate cutters, ESAB uses three adaptive-optic lenses that adjust their shapes on the fly to prevent beam divergence as the head moves.
Like its competition, the company has made steady improvements to linear-motor technology. It has boosted the initial 8500-ipm (215 m/min) rapid traverse rates to 10,000 ipm (255 m/min), and 2-g acceleration to 3 g. The newest machines deliver this speed and responsiveness while maintaining position accuracy of at least ±0.001″ (0.025 mm), and processing accuracy is 0.005-0.015″ (0.13-0.38 mm), depending on material type and thickness.
Lutz Ehrlich at Finn-Power International Inc. (Schaumburg, IL) says linear motors have boosted productivity of the company’s laser cutters by approximately 50% without sacrificing accuracy and repeatability. And since the builder introduced its linear motor-driven laser cutter in 1999, advances in the technology and its application have increased the productivity of subsequent models by 30% in some applications.
Builders exploit the benefits of linear motors in various ways. They, for example, have nearly eliminated the unproductive dead time that is part of any job for moving the cutting nozzle from cut to cut. By combining with the higher-power lasers available today, they also have built machines that can cut much faster, a benefit that is especially useful on long cuts. Perhaps the biggest impact of linear motor technology has been on contour cutting, where their ability to accelerate rapidly allows fast, precise cutting of even small contours with good edge quality.
Improving linear motor technology has increased the productivity of FinnPower lasers, such as this laser-punch combination machine, by as much as 50% over conventional systems.
Linear drive technology also has changed the way manufacturers are designing and building their high-speed laser cutters. “The challenge to maintaining accuracy here is not as much in the CNC as it is in the mechanical design,” says Ehrlich. “You need rigidity when moving masses around that quickly. If we were to put linear motors on a conventional laser, the machine would walk away because of the inertia.” Besides a rigid mechanical structure, builders also attempt to redistribute the mass of the machine, reducing the mass of its moving members.
To make linear motors less costly to install, Mazak Laser Corp. (Schaumburg, IL) designed a concept that eliminates the need for expensive chillers and glass scales. Rather than laying flat like conventional designs and having water lines running through them to dissipate the tremendous amount of heat that they generate, Mazak’s linear motors are hollow rectangular boxes. Enough air can blow through the center of these boxes to cool the motors, making liquid-based chillers unnecessary.
The company eliminated glass scales for positioning by transforming the motor’s magnetic segments into a scale. Its engineers discovered that the controller could read position directly from the segments if they were machined accurately enough. They also designed a reader that mounts on the carriage and counts the magnetic segments as it moves back and forth.
CNC advances and sophisticated control software are simplifying laser programming, setup, and operation. According to Cincinnati Inc.’s Neff, his company’s control automates much of the laser’s activity and gives operators access to the shop’s computer network. “Today’s controls are basically a PC on a network,” he says. “Anyone familiar with Microsoft Windows can navigate around a company’s computer network and pull in files easily from a programming system to a laser without having to go through an RS-232 port.” Moreover, operators can use the software on the machine controller for both programming the machine and nesting.
Zakrzewski says Bystronic has invested significantly to develop its Bysoft 6 programming software. The latest version, version 6.6, works on the builder’s press brakes as well as its laser and waterjet cutters. Users can import a CAD file, program the laser and brake simultaneously to cut the part, and simulate both cutting and bending on the computer screen.
The software selects the correct tools for each bend and the bending sequence automatically. Consequently, when the laser cuts a blank and releases it to the press brake, the operator need not struggle with setting up the brake to produce good parts. Tolerances should be tight enough for robotic welding, Zakrzewski says, and operators can use the software to accommodate last-minute deviations from the cutting plan.
Not all the benefits of modern controllers come from software that operators can access. Quite a bit happens behind the scenes, as control packages quietly optimize the process, often without the operator knowing it.
A simple example is software that “cuts corners” automatically during rapid traverses. Rather than allowing the head to move in a step motion-going up, over, down-the software shortens the travel path by converting the motion into a smooth arc. “That saves a lot of time,” says Ehrlich at Finn-Power.
Another example is software that eliminates close-loop feedback on Mazak’s HyperGear laser cutter. “The controller has so much processing capacity that not only does it know what geometry it needs to cut, but it also can look ahead to account for G forces and inertia in the motion system,” says senior VP Glenn Berkhahn. The machine needs this ability because its linear motors can accelerate at 3 G and maneuver faster than the controller can receive and act upon position feedback. As a result, Mazak’s engineers decided not to rely on a feedback signal, but to look forward instead.
Smart Sensors. Modern laser CNCs are also accepting and acting upon a variety of signals from sensors placed throughout the machines, even alerting operators to required maintenance. The Preview 640 control on Mazak’s HyperGear cutter, for example, can track the performance of filters, warn the operator that a filter is near the end of its life, and even stop the machine if maintenance fails to change it.
Based on light emissions from the plasma surrounding the cut, this CNC also can alert operators to check the cutting head for a dirty lens or nozzle. When it suspects the lens is getting too dirty, it can direct the machine to move it in front of a camera to check and, if necessary, can change the torch itself or just the nozzle. A magazine that can hold as many as ten nozzles facilitates replacement, and can also hold as many as four torches and even can store and use motorized reamers, taps, or grinders to remove spatter or perform other secondary operations.
In the case of the LVPLUS, the latest laser cutter from MC Machinery System Inc.’s Mitsubishi Laser Div. (Wood Dale, IL), the key sensor is called MEL’s Eye. Mounted above the processing lens, this photoelectric eye collects light emanating from the cut and transmits it to proprietary software inside the control. Based on spectral signatures, the software judges whether specific cutting activities are optimal and, if not, decides what action the machine should take to make it so.
Corrective actions can take many forms. For example, when it detects the light produced by red molten metal, the controller will stop cutting, clean the nozzle, and resume cutting. When it sees a blue light coming from the nitrogen surrounding a cut in stainless steel, it knows to slow the machine down until the blue arc goes away to avoid losing the cut. A lack of light during a piercing operation indicates that the laser has broken through the material and can begin traversing the cutting path.
“In conventional piercing, many people put in a two or three-second buffer to make sure that the laser pierces through the hole every time,” says senior product manager Jeff Hahn. The eye eliminates the need to wait, and also permits what Hahn calls truly automatic focusing.
“Autofocus is a bit misleading,” he explains. “What most people call autofocus is a lens with a motor on it that moves the head into position automatically [when the laser begins cutting a different material]. But you still have to tell it where the zero position is, and that’s a manual operation without a sensor like MEL’s Eye to find that point automatically. Automating this part of focusing the beam eliminates a source of variation that affects the quality of the cut.”
Speed in 3-D. Drives, computers, and sensors may take the lead in today’s advanced laser cutting technology, but builders have not ignored design of the machine’s superstructure. This was a major consideration in two recent concepts for 3-D cutting.
The Domino HS cutter from Prima North America Inc. (Chicopee, MA), for example, can move at 5900 ipm (150 m/min) in both 2-D and 3-D modes-faster than some 2-D cutters. The machine’s superstructure contributes to its speed by preventing vibration that usually occurs when conventional 3-D machines try to cut flats as fast as 2-D systems. A synthetic granite frame dampens vibration and inhibits thermal expansion, and a resonator integrated into the machine’s structure also adds a measure of stability. Consequently, accuracy and repeatability are 0.001″ (0.025 mm).
Designers also kept moving masses low by relying on flying optics for 2-D cutting and a combination of flying optics and a cutting head to generate the five-axis motion necessary for 3-D cutting. “Also, instead of using traditional ballscrews, we are using a fixed-spindle and rotating-nut drive, which can accelerate much faster and reach much higher speeds,” says Prima’s Thomas Burdel. Different programs for 2-D and 3-D cutting to allow the machine to optimize its speed for straight-aways and corners in 2-D shapes and contours on 3-D parts.
Good design also helps robotic cutting of 3-D parts. In the past, builders of many laser-cutting robots were forced to use smaller motors and lighter drives to keep tooling weight within the robot’s payload capacity.
To make robotic laser cutting more robust and thus more attractive to users, Laser Mechanisms Inc. (Farmington Hills, MI) developed a remotely actuated cutting head. The company’s engineers got the idea to move the motors off the arm while developing equipment for an automaker cutting hydroformed rails. The laser-cutting robots that had been doing the job were down too much, optics required frequent cleaning, and external cables snagged on tooling and broke.
“When we designed this head, we completely sealed the optics chamber and eliminated all external cables,” says Laser Mechanisms’ Mike DelBusso. “That led us to go a step further and remove all the motion devices from the head.” In addition to allowing the designers to specify a more robust motor, this move also helped them to solve the contamination problem.
Material handling innovations are transforming laser cutters into flexible-manufacturing cells. Most builders offer towers that can contain a variety of work materials, from 3/4″ (19-mm) steel plate to 16-gage stainless. The cell operator downloads the appropriate programs, then the controller selects the material from the appropriate shelf in the tower and loads it onto the machine for processing. Cut parts are placed into a tower or conveyor on the other side for transfer to the next operation.
Although loading fresh sheets into the laser cutter is a smooth process, a bottleneck exists for unloading. Separating the good pieces from the remaining web or skeleton has been too tricky a business for automation to handle and usually requires human judgment and agility. “So, most lights-out operations give you a tower or pallets full of skeletons and parts,” says Elizabeth Kautzmann, laser product manager, Salvagnini America Inc. (Hamilton, OH). “In the past, this has always been handled by people separating the part from the skeleton on the next day.”
To remove this bottleneck, Salvagnini engineers are developing software that can plan cutting paths in a way that would allow robots to transfer the parts to the next process automatically. “Our vision is to have the laser-cut parts already put through a panel bender or sitting in front of a press brake,” Kautzmann says.
The first version of this software is already at work in a factory making heating and air-conditioning units. It nests the pieces into kits or groups that can go to the next process together, putting them in an array of boxes that resemble the panes of a window.
Consider a 5 × 10′ (1.5 × 3-m) sheet. The software would begin cutting by dividing it into perhaps six pieces, three at the bottom and three at the top. Having a common line eliminates the small bits of web between them, which is a primary source of uncertainty and a major obstacle in automating the handling of parts. “It’s a very narrow piece of metal that has been stress relieved,” explains Kautzmann. “So it warps and can move and tip the cut pieces.”
After creating these panes, the laser goes to work cutting parts from them. Rather than cutting them out completely, however, it leaves what Kautzmann calls microtabs that keep the parts attached to the individual panes. If necessary, the software can direct the laser to cut interior scrap from holes and other features into pieces that are small enough to fall through the grate that serves as the cutting surface on most lasers.
Because the software has organized the remaining parts such that they all go to the same operation, the pane can serve as a carrier that a robot or other automated handling device can deliver to that operation. Although the operator at the destination still must punch or shake the parts from the carrier, the parts arrive at the right place automatically in a manageable manner.
Welding lasers have followed their counterparts in the cutting world in their quest for higher beam quality. The primary goal over the last decade has been to generate beams that can hold together better over long distances so the builders could increase the focal lengths of their lasers.
The extra focal length allows the laser to deliver a given energy density from greater distances. Consequently, lasers can weld using higher standoff to keep the optics away from weld spatter and smoke and reduce maintenance.
Better beams have other benefits, too. Trumpf Inc.’s Laser Technology Center (Plymouth, MI), for example, has been able to exploit them to reduce the time its TrumaScan L4000 remote welding system spends traversing from weld to weld. Trumpf engineers borrowed the scanner technology found in laser markers to design what could be called a laser marker on steroids. Rather than manipulating a 10-150-W beam over the workpiece, the programmable mirror they developed can deflect 3.5-6-kW laser beams over a working area large enough for welding automobile body panels.
The major advantages of the design are speed and accuracy. As in laser marking, the beam can jump from point to point very quickly. “Users don’t have to move a heavy part in a fixture around underneath the beam source,” says Greg LaManna, product manager for Trumpf’s CO2 lasers. “They don’t have to move a focusing module around over the top of the part.” Because the only moving member is the mirror, system inertia is low and repeatability is ±0.2 mm.
The technology excels in applications that require several welds over a fairly large area. In one automotive application, the scanner design outperformed a conventional laser roughly fivefold, according to LaManna. It completed the welds in 5 sec, whereas the conventional laser took 23 sec and a resistance spot-welding unit took 30 sec.
Trumpf has advanced the idea to the next level of sophistication by deploying the beam over two welding stations on its L4000 system. While one station is welding, the other one can be handling the material, unloading welded assemblies, and loading a fresh set of parts. “So you maximize laser usage and improve the throughput of the system,” notes LaManna.
Nd:YAG lasers have reaped the benefits of better beam quality, too. Trumpf has developed a YAG laser that uses a thin disk, rather than a rod, to generate the laser beam. “Because the disk is significantly smaller than a rod, we’re able to cool it much more effectively,” says Trumpf Nd:YAG product manager David Havrilla. “Better cooling gives us higher beam quality, which allows focusing the laser to a small spot or increasing the focal length.”
The ability to focus to a smaller spot creates higher power densities with less overall power, and allows transmitting the beam through a smaller fiber. One model, for example, transmits 1 kW through a 150-µm fiber. The result is welding and cutting speeds that are higher than those that are possible with conventional lamp-pumped YAG lasers, Havrilla says.
Another benefit of the disk laser is that it places no limit on the length of the fiber optics. At certain power levels and fiber diameters, long fibers tend to reflect energy back into lamp pumped or diode-pumped rod resonators and create instability. “Laser manufacturers get around this phenomenon by limiting the length of fibers at these power levels and fiber diameters,” says Havrilla. Because the disk contains much less lasing material, this phenomenon is eliminated in disk lasers.
Family Business Grows With Laser CuttingSouth Jersey Metal (Deptford, NJ) has been manufacturing custom kitchen food service equipment since 1946.Director of Operations Jared Wagner explains that the company’s custom manufacturing resulted in long lead times, a situation he hoped to change by implementing new manufacturing methods. “The biggest hurdle our company needed to overcome was the time it took to go from approvals to the finished product,” Wagner says. “Our work is very labor-intensive, so our goal was to reduce or eliminate some steps in the process going from flat sheets to forming.”
A November 2003 consultation with a sales rep for Mitsubishi Laser(Wood Dale, IL) gave Wagner insight into how laser manufacturing could help South Jersey Metal increase productivity and shorten lead times. But, the company wasn’t prepared to invest in a brand-new machine.
“I didn’t want to buy a used laser at auction,” Wagner says. “Without Mitsubishi’s pre-owned program, we couldn’t have made the leap into laser manufacturing.”
South Jersey Metal purchased a Mitsubishi 3015LZP-3020D laser with automatic pallet changer in November 2003. Wagner says he selected Mitsubishi mainly because the company designs and manufactures its own resonators.
Results were immediate. “The amount of time it used to take us to go from flat stock to bending was cut in half,” Wagner recalls. “Before the laser, the fabrication process included shearing, layout, notching, and punching. “Now all we do is load the metal and press the start button.”
Improved productivity helped offset big price increases for the company’s staple work material, stainless steel sheet. “Over the past year, stainless steel prices have increased 35%,” Wagner says. “The time saving our laser achieves helps us counter those material costs and keep more consistent prices for our customers.” Laser technology has also increased the company’s client base, allowing contract cutting of flat architectural and ornamental sheet, he adds.
Flexible Laser Boosts Fab BusinessOne of the main ways Marks Brothers Inc. (Portland, OR) has succeeded at taking on new and challenging jobs is by using state-of-the-art equipment.Although Marks operated three lasers, managers recognized that making preformed parts on the systems often required secondary operations such as shearing, notching, punching, and machining. All these steps increased processing times and manufacturing costs.
After some research, the company purchased a Domino 1530 high-speed laser cutting system from Prima Laser Tools (Chicopee, MA). President Jon Marks explains the decision: “We found only one other machine like the Domino five-axis cutting system in our market region. But we also saw an advantage in the very unique, versatile system.”
According to Marks, the system has reduced part costs up to 80% because it can produce intricate components with 2-D and 3-D features four times faster than traditional methods. The machine’s five-axis cutting capability eliminates up to four secondary processing steps for some parts. For example, the system’s gantry-mounted cutting head enables bevel cutting, eliminating costly mechanical chamfering operations. The machine has also opened new markets, such as cutting features into preformed tubes used in sporting goods applications.
Marks says the machine’s overall productivity more than offset the modest learning curve involved with its operation. “We are now taking on jobs in new markets. We actually increased our business by almost 40%,” he concludes.
Laser Replaces Plasma For Truck PartsMcNeilus Truck and Mfg. Inc. (Dodge Center, MN) manufactures body components for refuse trucks and concrete mixers at the rate of 5000 per year. Concrete mixers are available in multiple sizes, and refuse truck bodies come in 21 different major configurations. The company also produces parts for older models, as well as replacement parts for competitors’ trucks.McNeilus was using a variety of plasma torches and plasma-punch machines to cut parts from steel plate and sheet. “However, we recognized that laser-cut parts lend themselves more towards automation because of their consistency and higher quality,” says director of manufacturing Joel Urch.
Urch followed laser technology, noting improvements over the past few years. “When a 4000-W laser could cut 1/2″ [12.7-mm] steel quickly, we really got excited, because we run a steady diet of hot-rolled steel in thicknesses from 20 gage up to 3/4″ [19 mm],” he says.
Before McNeilus bought its first laser, the company looked at four manufacturers. Urch checked out both the suppliers and shops using the equipment before settling on a laser cell consisting of two Bystar 2-D 4020 lasers with automatic, integrated material handling that moves the plates from storage drawers into and out of the lasers. Manufactured byBystronic Inc. (Hauppauge, NY), the lasers can handle sheets to 2 × 4 m in size.
“We liked that the sheet stays in one place and only the laser’s cutting head moves,” Urch says. “We cut a lot of heavier stock, and we felt moving the stock around on one axis would be detrimental to machine longevity. We also like that the integrated material handling system feeds both lasers.” According to Urch, the system runs around the clock, with untended operation on Friday and Saturday nights. Programming is done offline, and programs are sent to the lasers via Ethernet. Urch says Bystronic’s dynamic nesting program allows McNeilus to run multiple part numbers from a sheet, improving material usage and reducing scrap.
“We also use common line cutting with the laser to increase sheet usage, which a plasma torch can’t do,” he adds. “If you’re cutting out many different rectangles, you can basically set them next to each other. When you make one cut between these nested parts, they are separated. This makes your machine time more efficient and maximizes machine cutting time.”
According to Urch, the lasers have produced higher quality parts than plasma systems, which facilitates downstream automation and minimizes secondary processing. He says the machines’ beam-on efficiency (the time the beam is actually cutting) averages more than 82%, and sometimes tops 90% in untended operation. Installing the lasers allowed McNeilus to take a three-head plasma cutter out of service, and the result is more parts with less labor input, he adds.
Cutting Head Retrofit Simplifies Laser OperationDowding Industries (Eaton Rapids, MI) fabricates a variety of heavy-gage steel parts using flatbed laser cutters. Over half the company’s lasers were manufactured by Mitsubishi and were more than three years old.Dowding often runs at full capacity, so laser maintenance is closely monitored and completed on schedule. Still, unexpected failures occur.
Case in point: one of the motor-driven, adjustable-focus cutting heads on a machine froze in a usable position. Part fabrication continued while staff began to explore options to repair or replace the head. Things went from bad to worse when a catastrophic crash ripped the head off the machine. The laser burned the inside of the head, making it unusable, so a quick decision and repair was needed to get the laser cutter back into production.
According to Senior Laser Technician Dwayne Porter, the cost of a replacement head from Mitsubishi was nearly $30,000. An option was to purchase a non-OEM head from Germany, but it too was expensive and did not have the features Dowding was looking for.
For less than half the cost of the German-made head, Dowding decided to try a new cutting head from Laser Mechanisms Inc. (Farmington Hills, MI). The head offered multiple features, including magnetic crash protection with integral switching to shut off the laser immediately in the event of a crash.
Magnetic crash protection works by allowing the head to separate from its magnetic base during a crash. The crash impact energy is not translated to the gantry, and the head is not severely damaged. More importantly, the laser shutter is automatically closed when the head and base separate. This prevents dangerous laser exposure from damaging the equipment, injuring personnel, or starting a fire. The head resets to usable condition in about 30 sec after a crash.
Other features that immediately saved time included front access to lens cartridges, which cut lens inspection and replacement time to 30 sec, and a hand-adjustable external vernier scale to adjust fine focus without tools.
Laser Cuts 120+ Hours a WeekWood-Mizer sawmills-from powerful hydraulic units for high-volume professional sawyers to manual mills for woodworking hobbyists-have been sold in more than 100 countries over the past 25 years. The company maintains quality and competitive prices by judicious use of new manufacturing technology.Case in point: laser cutting. In 2000, the company began searching for a new metal-cutting laser for its New Point, IN plant. Jeff Heidlage, VP-New Point Operations, says the company evaluated laser systems from various suppliers before it selected a CL-6 laser cutter from Cincinnati Inc. (Cincinnati).
With a 5 × 10′ (1.5 × 3-m) table, dual pallets, and 2000-W cutting power, the system met Wood-Mizer’s operational and quality requirements at a good price, according to Heidlage. More than four years later, he has no regrets about the decision. “We turn the machine on Sunday night at 10, when third shift starts, and turn it off Friday night or sometime the next Saturday,” he says. “It runs 24 hours a day, five to six days a week, depending on if we need to run overtime.”
Wood-Mizer processes more than 3200 different parts on the laser, ranging from 16-gage to 1/2″ (12.7-mm) thick plate. About 90% of parts are carbon steel, with the remainder being stainless.
To minimize work in process, “everything we cut on the laser is a short-run quantity,” Heidlage says. “The number of pieces we run is also keyed to how much storage space we have assigned in the welding department for that particular part.” The laser’s ability to cut tabs and slots also allowed redesign of some parts for simpler fixturing and assembly, he adds.
Besides its own production parts, the plant does some contract laser cutting. One outside customer had a 3/4″ (19-mm) thick part that Wood-Mizer would flame cut, edge finish, then send to a machining center for holemaking. “Now, we cut everything on the laser, eliminating edge finishing and hole machining,” says Heidlage. “Cost per piece dropped by over 75%.”
This article was first published in the March 2005 edition of Manufacturing Engineering magazine.
Published Date : 3/1/2005