LASERS KICK IT UP A NOTCH

Sheet-metal cutting is the single largest global industrial laser application by sales revenue. Three years ago, over 35,000 laser cutting systems of diverse configurations were installed worldwide, total revenues for this sector exceeded $2.7 billion, and annual growth was projected to reach 10 percent or more for the foreseeable future. Just 18 months later, this installed base had expanded to more than 40,000 units. Approximately 1,500 high-powered laser cutting systems were being sold annually in North America. Most of these systems used CO2 lasers.

Though the economic downturn slowed everything down and the overall industrial laser market is projected to fall 32 percent this year alone, the technology continues to pursue higher power and beam quality, improved reliability with lower maintenance, faster processing speeds on thicker metals, and fully automated procedures for unattended operation. These advances have created two major shifts that are transforming the industry: one from 2D to 3D laser cutting and the other from CO2 lasers to fiber lasers.

DIVERSIFY OR DIE: MOVING FROM 2D TO 3D

Once upon a time many shops ignored 3D laser cutting, assuming the systems were complicated, expensive, and difficult to use. ?The industry used 2D lasers to cut flat sheet metal,? says Thomas Burdel, vice president of sales and marketing at Prima Laser Tools (Chicopee, MA). ?Much of the demand for higher productivity in sheet metal processing was filled by high-acceleration motion control and elevated laser power that boosted 2D laser cutting speeds. And replacing oxygen with nitrogen assist gas overcame speed-limiting oxidization.?

But the current economic climate forced fabricators to rethink a hard truth: virtually any laser sheet system can cut light gage sheet metal, leaving shops that only use flat-sheet cutters vulnerable to fierce competition. The new rule in sheet metal fabrication became diversify or die. Become a one-stop destination that processes metal sheet, plate, tubing, formed parts and other profiles, or watch the business dry up. The time to move from 2D to 3D arrived.

While economically attractive, cutting metal with a tilted laser beam can be deceptively difficult. In typical 2D CO2 laser cutting, the laser beam is oriented perpendicular to the workpiece surface. The beam melts the metal while a jet of assist gas blows the molten material out of the cut kerf. ?The gas jet is much larger than the focused laser-beam diameter, meaning only a small part of the jet passes through the narrow cut kerf while most of the gas is deflected,? explains Pieter Schwarzenbach, vice president of laser technology at Prima Laser Tools. ?This problem compounds when the beam tilts for bevel cutting on a flat-cutting system fitted with a 3D head. The greater the tilt, the less effective the system is in blowing out the molten metal from the cut kerf.?

Tilting the beam may also make a machine unable to handle a cut, because the cut depth grows larger than the sheet thickness once the angle of incidence deviates from 0 deg. ?Just tilting the beam 45 deg can increase the effective part thickness from ¼ in to nearly 3/8 in,? notes Schwarzenbach. ?Parameters must be adjusted. The X and Y axis must move in a non-typical trajectory because of the offset between the Z axis and the focal point. This offset is a function of the bevel angle, and the trajectory calculation is a tool-correction offset evaluation. In extreme cases, the cut kerf quality might also be compromised.?

New laser cutters and their software address these issues so that systems can effectively run applications by tilting the beam. ?In fact, laser bevel cutting eliminates additional processing on the workpiece,? says Burdel. ?For example, welding preparation is a time-consuming and difficult process when parts are conventionally laser cut. But with a tilt cut, the laser delivers the bevel during the initial profiling process and eliminates an entire process step, including planning, working space, personnel, tools, logistics, stocking, and rejected parts.?

Schwarzenbach reminds operators to be aware that reflected laser light can present a safety hazard. ?This means they should perform the piercing process with a perpendicular incidence (angle = 0 deg). As soon as piercing is complete, they can then tilt the cutting head to the required bevel angle.?

Another example of how the tilt beam slashes process time and operating costs is the high-speed trimming of hot stamped automotive parts. ?Because these parts are made from hardened steel, conventional stamping tools would wear out in no time,? explains Burdel. ?The tilt beam also lets shops produce more complex parts, such as slanted teeth for helical gears or simple beveled holes for countersunk screws.?

He points out that laser systems featuring 2D and 3D capabilities can open avenues to new revenue for shops. ?These systems are highly dynamic and stiff, offer high resolution for the required timing and positioning, and they?re surprisingly affordable,? says Burdel. ?Adding an optional rotary axis for profiling gives shops a low-cost, all-in-one machine that pumps out a variety of jobs.?

Walt Corey, president of Pickwick Manufacturing Services (Cedar Rapids, IA), totally agrees. Pickwick is a contract metal fabrication firm that began serving international clients back in 1939. Besides being one of the 400 fastest-growing, privately held manufacturers in the country, Pickwick has the distinction of purchasing the first sheet laser in the U.S. back in 1985.

The company follows a simple business equation ? save time, save money and increase sales ? with a dramatic solution: a robotic 3D laser that resides in the Fabrigear 300, a laser-cutting system that transforms 26 ft lengths of tube, channel, beam and angle and extrusions into precise, ready-to-weld or assemble pieces. ?The ability to cut precise, tight joints and tabs and slots out of structural steel saves a manufacturer or contractor hours of labor,? explains Corey. ?One of our customers recently eliminated the need for a $25,000 custom welding fixture thanks to this laser cutter.?

Corey believes that this laser system does for structural steel what the sheet laser did for sheet metal. ?There are no limits and no tools to wear out,? he says, noting that the system?s 26 axes provide three dimensions of laser accuracy to joint preparation, which eliminates machining and fit-up problems. The machine automatically loads and unloads and reduces assembly steps with its ability to perform multiple tasks in one pass. ?In a single operation that takes just minutes, we can cut a tube or beam to length, provide bevel edges, cut and tap holes and more,? explains Corey. ?Automated processing provides far greater precision, speed and quality than manual drilling, cutting, beveling and so on. Separate setups and operations are things of the past.?

Pickwick has developed applications for the Fabrigear in the environmental, wind energy, agricultural and other industries. According to Corey, the system takes only 80 minutes to complete one structure that previously required six hours to complete in three separate operations. ?We have begun collaborating with our clients to develop methods that eliminate fixtures and tack welding and save them even more costs and time. When it?s applicable, this system typically saves huge amounts of labor,? adds Corey. ?It fits in perfectly with the lean philosophy and takes structural steel processing to an elevated level of automation to fit our customers? needs.?

There?s no argument on that from Roger Byers, president of Byers Precision Fabricators (Hendersonville, NC), which offers full-service 5-axis laser processing to help reduce costs for manufacturers in the automotive, aerospace, energy, and pharmaceutical industries.

In 1942, Roger?s father Paul opened a general sheet metal shop in Hendersonville called Byers Sheet Metal Works, which quickly became one of the largest ductwork and roofing contractors in the state. The company
grew and evolved into a premier industrial precision fabricating job shop with an ultra-modern plant that now uses a Prima Rapido 1532 5-axis laser system equipped with a 3.5 kW CO2 laser to cut steel, stainless, aluminum, ceramics, plastics and other materials on simple 2D and more complex 3D jobs. Two cutting heads cover a wide range of material thickness. Catia Fastrim software is used for fixture design.

?We can cut and trim hydro-formed, spun, deep drawn, and stamped parts for a more economical trimming solution than additional tooling or trim dies,? says Byers. ?The laser can produce features at an angle close to the horizontal and in areas inaccessible by other machining methods. 3D part contouring is not a problem.? These capabilities allow the shop to provide rapid prototyping services for customers based on the model data they provide, or add new features to existing parts. Outsourcing to Byers Precision reduces the cost for customers because no capital expenditure, ongoing operational costs, upgrading costs, or operational changes are required on their part.

For job shops needing more flexibility at an economical cost, the compact SG-U44 production laser with Robo Feeder from Mazak Optonics Corporation (Elgin, IL) automatically feeds tube, pipe and structural material and performs (1) high-speed 2D processing of sheet metal and plate, (2) 3D cutting of pre-formed parts, and (3) 3D-rotary cutting of tube, pipe and structural. This system is ideal for fabrication job shops seeking to diversify their markets, parts suppliers supplying hydro-formed or stamped parts, and machine shops that are now machining thick plates or tubing.

In rotary mode, the SG-U44 performs 2D and 3D cutting of tube, including rectangular, round, and triangular pipe as well as C, H, I and L-beams within a 6.0 in diameter. The 5-axis torch and simultaneously controlled chuck let the machine fabricate ? in one operation ? precise angle cuts, weld-prep bevels and advanced contours such as saddle joint cuts. The 64-bit control incorporates illustrated fill-in-the-blank screens to quickly program such complex contours and other cuts.

The Robo Feeder option enables processing of mill-length pipe and includes a feeder unit, control and 4 jaw scroll chuck. The workpiece diameter ranges from1.1 in (28 mm) to 6.02 in (153 mm). The maximum supported workpiece weight is 330 lb (150 kg). The material supply stroke is adjustable up to 49.21 in (1250 mm). Special clamping jaws are tailored for square, rectangular and H/I/C shaped material. With its multi-axis torch, the SG-U44 also laser-cuts stamped, hydroformed and spun pre-formed parts, as well as high-speed 2D cuts and bevels in flat material.

With its small footprint, this system can process any length pipe and up to 4 ft x 4 ft x 7/8 in sheet. A choice of resonators up to 4 kW allows fabricators to choose the power most efficient for their business. Space CAM and FG CAD/CAM software options generate NC code from a 3D CAD drawing, imported or crafted in the system. Space CAM can also generate code for a slot-and-tab workholding fixture.

For fabricators focused on work with heavy tubes, the TruLaser Tube 7000 from Trumpf, Inc. (Farmington, CT) can cut tubes and profiles with large diameters and wall thicknesses without sacrificing productivity. With up to 3.6 kW of laser power and a 0.6 in to 10 in clamping range, this system is ideal for a wide range of new applications that process tubes up to 30 ft long with a maximum weight of 496 lb.

?A tube inside a tube? might be your initial reaction when you see this high-end laser cutting system processing tubes inside a tunnel-like safety enclosure and then, depending on size, moving them forward to the brush table or ejecting them to a parts container behind the machine.

This machine can boost productivity significantly over conventional sawing, drilling or milling. One example is the short set-up time when changing programs. Nearly all of the adjustments depend on profile specifics. Values that must be entered at the machine and the loading unit can now be handled by the parts program. The self-centering chucking jaws do not need to be changed. The rollers that provide support and lateral guidance for the tubing automatically adjust to the diameter. Even the integrated scrap container in the feed station is emptied without operator intervention.

The FocusLine function automatically adapts the laser focal position to the material type and thickness. The machine?s software independently adjusts to the focus parameters given in the technology table, eliminating any set-up effort. A new slender cutting head with a 6 in lens and new style clutch provides flexibility and process safety.

The LoadMaster Tube magazine holds up to 8,000 lb of raw material and fully automates the system with a pivoting feed support that holds and positions a number of tubes at constant orientation. It measures the pipe length and adjusts the position of the grippers accordingly. This loading unit performs a feasibility test to compare the tube geometry with the parts program. Special profiles and small batches can be fed by a conveyor section.

The entire system operates with a new version of TruTops Tube software to create sophisticated processing strategies. Built around a comprehensive database of technical knowledge, this software enables complex tube profiles to be fabricated easily, precisely and reliably. This software saves time by making it possible to position one 3D tube on another, instead of designing and programming individual tubes, and modifying the length, width, height, wall thickness and spacing between cut-out parameters to generate any number of variations.

But make no mistake regarding the advances taking place in laser technology. Apart from the buzz about 3D laser cutting, 2D sheet metal cutting applications are alive and well, with new innovations and higher speeds that deeply support the lean operations of many shops.

ALIVE AND WELL: INNOVATIVE AND FAST 2D
For sheet metal fabricators that need reliable cutting performance at an affordable price-performance ratio, the Sirius is an automation-ready flying optics laser cutting system from LVD Strippit (Akron, NY) that processes parts at optimal speeds and accelerations to suit the part geometry. It achieves quick and precise positioning with axis speeds up to 120 m/min.

Modular construction permits the user to select the configuration that works best for their application and budget. The standard laser cutting system features 3 m x 1.5 m integrated shuttle tables that maximize uptime by allowing one table to be loaded while the machine cuts on the other table. Table change time is a mere 25 seconds.

This system is equipped with a high pressure laser cutting head that produces exceptionally clean cuts. A crash-protection system protects the head from damage after collision with the workpiece. A total power control feature automatically adjusts the laser power in relation to the cutting speed, ensuring an optimal cut at every contour width and minimizing the heat-affected zone. The edge function feature processes sharp corners cleanly, particularly in thicker materials.

The cutting head accommodates a 5 in or 7.5 in water-cooled quick-change lens that uses a self-centering system for fast changeover and minimal set-up. Lens calibration is programmable and quick. Sirius employs a GE Fanuc RF excited fast axial flow 2.5 kW or 4 kW CO2 laser that is fully integrated with a GE Fanuc PC-based CNC control, drives and motors for superior processing speed, high reliability, low operating and maintenance costs. The control reproduces programmed contours and creates acute angles at high speed. The laser power is matched to the vectorial speeds for a constant cut width and a small heat-affected zone.

All parameters, diagnostic and start-up procedures are conveniently displayed on the screen. The 32-bit control features powerful mathematical capabilities and an extensive material library. Optional CADMAN-L 3D offline programming software provides a comprehensive laser-cutting CAM package that includes an integrated 3D design and unfolding module for easy importing of 2D and 3D designs, and automatic unfolding and generation of flat patterns from 2D or 3D files.

CADMAN-L 3D incorporates fully automatic, semi-automatic or manual nesting and optimizes cutting and machine parameters to maximize sheet utilization. Advanced features include cutting path optimization, common line cutting and high-speed communications via Windows, networking or DNC link to maximize machine productivity.

By adding various components, the system can expand into an automated load/unload system with a compact tower that creates a flexible manufacturing cell for ?lights out? operation. The tower system includes a shelving unit for storing raw material and finished parts that works in concert with the material handling unit to fully load and unload. This expanded system uses NC Focus for programmable adjustment of the focal position without operator intervention, provides Process Control for piercing and cutting, and an automatic shut-down feature.

For lean fab shops trying to reduce labor content even further, the HyperGear laser cutting system with the Fab Shop Type-A FMS and OPTO-PATH Sorting System requires minimum operator intervention. This system, from Mazak Optonics, uses an advanced FMS that combines all the benefits of automated setup and valued-added process integration from multiple laser cutting machines, along with automated raw material loading and subsequent unloading. It also sorts cut parts from scrap skeletons.

On its own, this laser system incorporates intelligent features that automatically optimize setups, notify maintenance, and achieve the fastest cutting speeds for every material type and thickness to improve cash flow by processing more parts per working day. The system uses an automatic torch and nozzle changer and automatically sets up focus lens position, nozzle-to-material distance and beam adjustments.

A next-generation MAZATROL PREview 640 PC control and linear drives enable the machine to cut at unmatched 3G acceleration speeds, yet with the precision to maintain perfect corners, tight dimensional accuracy and roundness on contours. This CNC monitors key cutting conditions to predict failure conditions, prevent them where possible, and minimize recovery time to allow extended hours of unmanned operation at optimum productivity. The unique air-cooled linear motors and stainless sealed protection covers eliminate the need for costly chillers or bellows.

A quick-change piercing gun combined with Mazak software automatically determines the optimum sheet pierce sequence. The piercing torch provides fast, stable piercing of thick plate while reducing heat build-up that can deform the sheet. A nozzle-grinding system saves costs by enabling the machine to recondition its own nozzles.

The 4 kW or 2.5 kW laser can process the thinnest painted galvanized steel up to 1 in mild steel on either a 5 ft x 10 ft or a 6 ft x 12 ft bed. This laser cutting system can reach unheard-of production capacities when processing a wide variety of material types and thicknesses with varying lot size requirements, including parts requiring tapping and chamfering. Its advanced material handling and parts sorting systems include material stockers, magnetic sheet separators, scrap removal forks, scrap bins or conveyors, multiple finished worksheet tables, a unique 7,200 vacuum pad pick-up device and parts separation.

Smart System Software and e-Soft play integral roles in NC programming, optimum nesting of parts and auto-programming, and FMS activation of any of the 7,200 vacuum pads matching a specific part profile to pick up and place only the finished parts, leaving the scrap to be taken away to the scrap bin or conveyor in one step via the scrap fork.

While traditional CO2 lasers continue to dominate the laser cutting sector of metal fabrication, the fiber laser is starting to make inroads into sheet metal applications.

ENTER THE FIBER: A CUTTING EDGE SOLUTION
Solid state fiber lasers first appeared in the sheet metal fabrication market about five years ago, using an optical fiber doped with low levels of a rare earth element such as Ytterbium as their lasing medium. Their pumping mechanism is the laser diode, another solid state device. What competitive advantages do they promise for cutting metal?

?Being completely solid state, fiber lasers are very compact and much smaller than an equivalent CO2 gas laser,? answers Paul Hilton, technology manager at TWI (Cambridge, UK). ?They are very efficient in energy usage, up to four times better than some existing CO2 lasers. They have no recognized consumables. Their laser diodes have projected lifetimes of about 100,000 hours and require essentially no maintenance.? Hilton believes that fiber lasers represent the first serious alternative to the CO2 laser since laser cutting was introduced 40 years ago.

Yet only a relative handful of fiber laser systems are currently installed for sheet metal cutting, with a value of just a few million dollars. Aside from the economic downturn, why haven?t they made more of an impact in sheet metal fabrication?

?Fiber lasers are very effective for precision or thin-sheet metal cutting, but they have not necessarily been the best choice for thicker metal in the past,? explains Tom Huasken, director of photonic market research at Strategies Unlimited (Mountain View, CA). ?Since job shops typically prefer a proven tool for both thick and thin sheets, the best candidate has been the CO2 laser, whose initial cost can be very low because it is already a mature technology.?

But as fiber laser technology matures, its cost per kW becomes increasingly competitive with CO2 lasers as its low maintenance and total cost of ownership align more closely with the lean manufacturing needs of job shops. This makes fiber lasers ideal for those niches in the industry that focus on thinner exotic alloys. ?Fiber laser cutting speeds have already reached almost 60 m per minute on thin materials such as 0.8 mm thick steel,? says Hilton. ?But they can also cut stainless steel and aluminum effectively. With more attention to the interaction between the assist gas flow from the cutting nozzle and the molten material ejected from the kerf, the quality and speed of fiber laser cutting will continue to improve.?

Fabricators are discovering this technology in different system configurations. For shops where space is at a premium, the L1Xe from Salvagnini (Hamilton, OH) is a fiber optic laser cutter for sheet metal fabrication that uses only one mirror, no gas consumables, no turbine, no glass tubes and no moving parts. By eliminating many of these restrictive variables, this compact system is economical to own, energy efficient, and ecologically responsible.

The system uses a fiber optic resonator from IPG Photonics (Oxford, MA) that requires 50 percent less energy to achieve the same level of performance as a CO2 laser. It drastically reduces consumption through the high efficiency source (&#951; > 25 percent), which is considerably superior to a typical CO2 source (&#951; < 10 percent). The cooling circuit is only about one-third the size of those required by CO2 lasers, which further reduces energy consumption.

Fiber optic laser technology harnesses light with a wavelength one-tenth that of a CO2 laser. This yields a high beam density and improved focus on thicknesses below 3 mm that permits high-speed laser cutting and rapid piercing. Through a wavelength typical of fiber, this laser can correctly cut highly reflective materials, such as brass and copper, as well as a wider range of materials.

This machine operates as a standalone laser cutter or as in integrated production cell with ASRS, sheet loaders and an MCL Cartesian sorter. Tradjust laser software is incorporated into the proprietary SiX controller to effortlessly run any application, generate the most efficient axis trajectories, and reduce the demands on the operator. The system?s uncluttered machine architecture is made possible by the absence of the optical path restrictions that characterize typical CO2 lasers.

In the food processing equipment sector, most of the drum mixers, industrial filters, slicers, food crushers and other machines are made from thin stainless steel which is cut and then processed. Two main dilemmas face the manufacturers of this equipment: cutting speed and post processing.

The Titan FLS 48 laser cutting system from Laser Photonics (Lake Mary, FL) solves the cutting speed issue by using a 2 kW to 5 kW upgradeable fiber laser that can quickly cut stainless steel, aluminum, mild steel, opaque plastics and most other highly reflective metals at the fastest cutting speed on the market. The system includes a Class I safety enclosure and direct drive motion control platform that is also excellent for deep engraving. This system has the smallest heat affected zone in the industry and requires no optical system alignment, laser service or laser replacement parts.

The ultra low power consumption of the Titan yields the lowest operating costs among all laser types. This high power, maximum throughput laser cutting system uses approximately the same amount of power as three vacuum cleaners. Other laser systems designed for the same applications are more than four times the size of the Titan and consume massive amounts of power.

In food equipment manufacturing, the post processing stage is a completely separate process from the initial cutting. Post processing ensures that all of the edges of the products are clean and safe for everyday use. When stainless steel was cut in the past, it was very difficult to guarantee the edges were completely smooth.

This is extremely important in this industry because jagged edges, no matter how small, will accumulate bacteria, dust and other harmful materials that are dangerous when working with any type of food processing. The Titan makes such a precise and clean cut, with no deformation of the metal or burnt edges, that none of the edges need any post processing at all. The system can cut intricate patterns with superior edge quality that speeds up the cycle time and directly improves the bottom line of the manufacturer.

Equipped with a single pallet shuttle table, this laser system is capable of large scale industrial cutting jobs. Because only one system is needed to complete both processing stages at one time, the Titan frees up more space in warehouses, uses less energy, and helps manufacturers become more environmentally friendly. During the next few years, watch for the cutting and marking of food processing machinery to improve in a big way as manufacturers move to fiber laser machines in mass.

As this technology matures in a future that demands leaner and greener applications, expect the aerospace, medical instrument and many other market sectors to follow close behind as fiber laser cutting expands throughout all of the sheet metal fabrication industry.

– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –

Mike Riley is the editor of Fabricating & Metalworking magazine.

Prima Laser Tools, 711 East Main Street, Chicopee, MA 01020, 413-598-5200, Fax: 413-598-5201, www.prima-na.com.

Pickwick Manufacturing Services, 4200 Thomas Drive SW, Cedar Rapids, IA 52404, 800-397-9797, www.pickwick.com.

Byers Precision Fabricators, Inc., 675 Dana Road, Hendersonville, NC 28792, 888- 693-7411, Fax: 828-692-5753, www.byersprecision.com.

Mazak Optonics Corporation, 140 E. State Parkway, Schaumburg, IL 60173, 847-252-4522, www.mazakoptonics.com.

Trumpf Inc. , Farmington Industrial Park, Farmington, CT 06032, 860-255-6112, Fax: 860-255-6424, www.us.trumpf.com.

LVD Strippit, Inc. , 12975 Clarence Center Road, Akron, NY 14001, 800-828-1527, www.lvdgroup.com.

TWI Ltd., Granta Park, Great Abington, Cambridge, CB21 6AL, United Kingdom, +44 (0)1223 899000, Fax: +44 (0)1223 892588, www.twi.co.uk.

Strategies Unlimited, 201 San Antonio Circle, Suite 225, Mountain View, CA 94040, 650-941-3438, Fax: 650-941-5120, www.strategies-u.com.

IPG Photonics Corporation, 50 Old Webster Road, Oxford, MA 01540, 508-373-1100, Fax: (508) 373-1103, www.ipgphotonics.com.

Laser Photonics, Inc. , 37 Skyline Drive, Suite 2103, Lake Mary, FL 32746, 407-829-2613, Fax: 407-804-1002, www.laserphotonics.com.

Salvagnini America Inc. , 27 Bicentennial Court, Hamilton, OH 45015, 513-874-8284, Fax: 513-874-2229, www.salvagnini.com.