Lasers march on - EuroBLECH 2012 review

With over 1,500 exhibitors from 39 countries and eight halls of exhibits, EuroBLECH highlighted developments that will shape the sheet metal sector over coming years, as Andy Sandford reveals Some broad themes were clear: the solid-state, as opposed to gas, laser – whether fibre, disk or diode – is carving out an ever greater market share in cutting and materials processing; and where metalforming is concerned, servo drives are becoming increasingly prevalent on press brakes, and more or less the norm on forming and stamping presses. The march of the fibre laser in metal profiling seems unstoppable. One exhibitor estimated that two years ago there were seven companies showing fibre laser-based profiling machines; this year, there were 25. With Mazak, LVD and Mitsubishi introducing new fibre lasers at the show, there are now no major suppliers that do not offer this technology. Bystronic (0844 848 5850) CEO Ferdi Toengi says that his company has had a new competitor in this sector every two weeks in the last two years – with the total standing at around 70 today. One reason for this is that companies such as Rofin are now selling fibre laser units as simple 'plug-and-play' systems that can easily be integrated with an existing X-Y table. Perhaps more importantly, though, the application range of the fibre laser is expanding, as higher power units come on the market and the control of the cutting process is better understood. For standard machines, 2 kW seems to have become the norm, while both Rofin and Bystronic showed 4 kW units. The received wisdom used to be that fibre laser machines would be the choice if you were only cutting thin material – up to, say, 4 mm – and that anyone regularly cutting a range of thicknesses would opt for a CO2 system. Now it seems that the tipping point has moved more into medium thicknesses – maybe 7 mm, 8 mm, or even greater. Bystronic's Mr Toengi acknowledges this: "Two to three years ago, we thought that the fibre laser would take maybe 15% to 25% of the market – and that forecast was wrong. We only saw it as being for thin sheet. Now customers are buying it for the medium-size ranges too, and we feel that fibre laser will take up to 50% of the market." From a slightly different perspective, Trumpf is now offering its solid-state disk laser technology across its complete range of machines and here again is looking at cutting thicker material. It offers as a standard flexible machine a TruLaser Series 3000 with a 3 kW source that can cut up to 20 mm of mild steel, 15 mm of stainless steel and aluminium, and 6 mm of copper and brass. Amada (01562 749500) was one of several at EuroBLECH highlighting the benefits and possibilities of welding with solid-state lasers – including high precision, minimal distortion, processing speed and good visual appearance. It used the show to launch its FLW series of fibre laser-based welding equipment. The range is designed to be modular, with powers from 1 to 6 kW, and includes a six-axis welding robot system. ROTATING LENS A particular feature of Amada's fibre laser technology is a rotating lens that can scan the beam to create a larger spot size. This allows it to bridge larger and uneven weld gaps, as well as optimising the heat input. Amada says the result is a precisely defined weld, with no unnecessary weld metal. This contributes to the cost-effectiveness of the process by minimising, or even eliminating, secondary finishing operations. On the Trumpf stand (01582 725335), presentations aimed at designers and production engineers stressed the advantages that could come from adopting laser welding and many of its exhibits were aimed at increasing its productivity in an industrial environment. These included a new 5-axis cutting and welding processing centre, the TruLaser Cell 300, integrated with a press brake and marking machine in a small production cell, and a larger TruLaser Robot 5020 welding cell with modular clamping and an automatic pallet changer having an integrated rotary axis. Other refinements included coaxial delivery fibres that can be used for both welding and cutting, without having to be changed over and a 'flat pack' approach to making small series welding fixtures, using parts cut on a 2D laser machine. Several companies were showing the next-generation technology of diode lasers. These convert electrical energy directly into light and are already used to 'pump' fibre and disk lasers. Now they are finding a growing range of applications in their own right, in welding, brazing, cladding and heat treatment. At EuroBLECH, German manufacturer Laserline (www.laserline.de) was demonstrating fibre-delivered diode lasers with output powers of up to 15 kW and, as European sales manager Dr Andre Eltze explained: "The advantages of the diode laser are lower investment cost, very small footprint and very high efficiency. As they are converting energy directly from electricity to light, they have the highest efficiency, by far, of any laser type; far higher than fibre or disk, reaching 45% wall plug efficiency. "They also have very low operating costs, because of this high efficiency. Since there is less power loss, the cooling requirements are lower and there is less thermal damage to the components, so you get a very long life." He adds that the slightly shorter wavelength, compared to a fibre laser, is also an advantage when welding aluminium, and Laserline is moving more and more into this area, both with and without filler wire. The technology has been in production at Audi for around three to four years, and an example of a Q5 boot lid was shown on the stand. SCANNING LASER For higher volumes, particularly in the automotive industry, scanner welding continues its steady growth. In this process, a robot-mounted unit scans the laser over the workpiece to produce spot, stitch or seam welds in the fly. This is an alternative to resistance spot welding – and potentially much quicker and offering a higher quality. Uwe Bergmann, director of scanner welding system specialist Bergmann & Steffen, says the process only really started to take off around 2006 when the first high power fibre and disk laser systems became widely available. Now he reckons that scanner welding has taken around 3% to 5% of the automotive spot welding market. His company has so far supplied 95% of its systems into the car industry – mostly in Germany, which seems to be leading the market. The first projects were on car seats, and today he has projects on doors, boots, bumpers, reinforcements and structural parts. Initial applications were on steel, but Mr Bergmann is now also seeing the scanner welding being used on aluminium components, too. He sees the potential for significant further growth in the technology. "At the moment, it is too expensive for general manufacturers, but it is a very flexible technology, very productive and could be easily adaptable to smaller volume production. The programming is all off-line and takes just a couple of hours, whereas a few years ago it would have taken weeks to program. We have already talked to some subcontractors about systems." The increased cutting speeds achievable on thinner material with fibre lasers have created a demand for faster, lower tonnage press brakes – a demand that is increasingly being met by machines with servo-motor drives. Amada's approach on its EG-6013 servo-electric press brake is to use a separate twin-motor drive unit on either side of the press beam, with two 3 kW motors providing the bending force and two 1.5 kW motors being used to give very fast approach and return strokes. For its new small E3 KinEtic electric press brake, Salvagnini (01989 767032) uses a servo-motor-driven planetary gear system, which gives a machine with a press force of up to 80 tonne and a positioning accuracy of ± 1 micron. Bystronic, too, launched an electric press brake, the 80 tonne 2m Xcite 80 E, which, it claims, is 2.5 times faster than a hydraulic press brake. This is achieved through a fast servo-motor-driven belt and pulley system, and a 'Fast Bend' safety control system that allows very fast approach speeds, without endangering the operator. Not all the electric machines on show were small. SafanDarley (0116 200 1777), which pioneered electric belt and pulley drive machines, showed its latest E-Brake, a twin-motor 130 tonne unit with a 4.1 m bed, aimed primarily at the cladding sector. VIRTUAL REALITY As well as faster machines, the other main focus for press brake innovation was faster set-ups. Here, SafanDarley showed an augmented reality system, which it is developing with Sony and Google, that allows the operator to see which tool is required and where it should be placed. This can either be done by wearing special glasses or by projecting images onto the machine. The system can also allow the operator to 'see through' the tooling to align the workpiece correctly with the back gauge. Both Amada and LVD (01295 676800) showed press brakes with automatic tool-changing systems. According to Amada, the time devoted to actual productive bending can be less than 50%, with the rest spent on set-up. It says that the combination of its HG-1003 servo-hydraulic press brake with the ATC makes batches of fewer than 10-off economical. LVD estimates that most companies with two or three press brakes make at least six tool changes a day on each machine. To reduce unproductive time, it developed its ToolCell machine – a press brake with integrated tool storage behind the beam and an automated system that uses grippers on the back gauges to change the tools. It says this ensures that the right tools are always available and properly set up in the right place every time, with no adjustment required – leaving the operator to concentrate on more productive tasks. While servo motors are starting to make an impression on the press brake sector, in just a few years they have almost become the norm in the power press market. Whereas a traditional mechanical press involved a motor, flywheel, clutch and an eccentric linkage, modern machines use servo motors to directly drive the slide. This gives a high degree of control for increased productivity, complex forming processes and energy efficiency. Now, five years after it launched its ServoDirect Technology (SDT), Schuler (01922 619100) used EuroBLECH to unveil its latest concept – TwinServo Technology. Instead of having a conventional press frame where the drive pushes the slide down, this uses two servo motors below the bed of the press that pull the tool down. This gives a lot more control for off-centre loads, greater rigidity, allows a design that requires around 30% less space and, because no potential energy is stored in the press frame, is much quieter, saves energy and protects the tooling. So far, Schuler has built a 1,600 tonne prototype, and plans to offer a range of transfer and progression presses, ranging from 1,000 to 3,000 tonne – with typical users being automotive OEMs and Tier 1 suppliers. First published in Machinery, January 2013