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Experts call for discerning approach to lasers

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MAJOR laser providers are warning customers to invest more time in understanding the technology to avoid costly misapplications.

David McHugh, CEO of LMC Laser , told Manufacturers Monthly when in comes to decisions about the suitability of lasers, it is important customers know the right questions to ask. This means, for example, being aware of factoring acceleration rate when gauging speed of a machine. “The key question is not how fast something goes, but how long it takes to cut the part.”

“People make a mistake not understanding the impact of certain things. The number of objects in a beam path, for example, is a critical question. How does the manufacturer maintain raw beam diameter? Why is one more applicable than the other? Proper service from the laser expert is important. Some people believe everything they are told there.”

McHugh’s advice comes as developments in speed and quality increase the popularity of lasers. “Manufacturers are becoming increasingly aware of lasers as they become impressed with the speed, and at every exhibition they are get faster and faster,” says Bernard Regan, CEO of HG Farley Laserlab.

Peter Bristow, CEO of Bristow Lasers , attributes ever improving speeds and increased pay-backs to two major factors: higher laser power and constant beam path technology. “Cutting up to 32mm of stainless steel (which I don’t believe anyone has done before) while having 6kW and 7kW has allowed us to be 30%-50% faster than any other laser. Constant beam path maintains beam quality for the high speeds, producing good quality cuts through 24 hour shift work.”

Sandvik, a supplier of stainless-steel products, just bought a 6kW 10m by 2m constant beam part system from Bristow Lasers, the largest ever built in the southern hemisphere. Bristow explains, “They’re now producing what were traditionally plasma cut parts, in some instances up to a third of the time at a much higher quality, with a much higher return on product. There’s a massive saving in welding, sheet pinup of multiple sheets compared with traditional methods.”

However, while speed is making laser technology more cost effective, Regan is concerned it is blinding manufacturers to alternatives such as plasma where he says developments are keeping pace.

“Some people spend too much on capital equipment and don’t look for the alternatives. Some of the new plasma systems are equal to most jobs the laser does.”

Regan emphasises the fundamental issue is cost. “If users have an application involving general ironware not requiring minute accuracies, there’s no need to spend a lot of money cutting it to within a couple of microns. You can spend three times what a plasma is on a laser, and the operating costs are higher. There’s been a proliferation of laser and we’re guilty in the market of poor application.”

However, Bristow says the laser expert should be able to provide clear information, particularly when it comes to exposed cuts or joints because there is rarely doubt whether plasma or laser is suitable. “There are not too many grey areas between one and the other.”

Laser advances

One of the significant developments recognised by both Bristow and Wayne Hooper, director of HVOF & Laser Technologies , is the diode laser but this emerging technology highlights the importance of customers understanding the capabilities of a new laser purchase.

Diode lasers are semiconductors producing coherent radiation (in which the waves are all at the same frequency and phase) spectrum when current passes through them. They have been used in optical fibre systems and CD players but are now making a mark in manufacturing.

Bristow says the manufacturing future of the diode laser is assured but customers still need to be aware this technology, which applies best to specific applications such as clean welding of stainless-steel, remains a very cost sensitive area.

“It produces very high quality cuts but it is really only good if users have high precision-jigging. In Australia it is very hard to find a customer prepared to put in the money on the jigging and the materials handling side which will match the capabilities of the laser.”

Bristow it will make inroads into high production line areas, such as the automotive industry and some components manufacturers but should remain a fairly specialised market.

However, growth for conventional laser systems continue to rise as proof of its capabilities continue to emerge. Hooper says, for example, laser cladding is finding more and more applications because of its inherent properties or advantages over other surfacing techniques.

“With laser cladding we’re achieving a welded or metallurgical bond with very low heating giving users surfaces that can be very hard, wear and corrosive resistant, without distortion and with a very small heat effected zone in the sub-strain. And as a result, in many applications, it’s superior to thermal spray and other surfacing techniques. We are developing that, but because it’s new technology, people don’t know about it yet,” Hooper said.

Meanwhile, Bristow is looking forward to developing higher powered 7kW with constant beam path technology to achieve quality 36mm and possibly 40mm stainless steel cuts.

He also points to major improvements associated with the treatment of raw materials of varying quality, particularly relevant to mild steel applications. “We’ve just finished two week cutting trials, cutting in 16, 20, 25mm which has been traditionally cut with unpredictable results. We’ve been working on nozzle technologies and other process technologies in particular so we can see the same results cut time and time again in locally sourced 20mm and 25mm material,” Bristow said.

The advice from the experts may take the edge of the excitement, but laser technology will remain something for manufacturers to watch.

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