Manufacturing with lasers is a global, multi-billion dollar industry. It has seen lasers replace conventional tools in many areas, enabling increased productivity, efficiency and quality. But experts believe we have only just begun to explore the true potential of lasers to have an impact on the engineering industry. It is thought they will play an increasingly important role in Britain as it continues to make the transition to a high-value-added, advanced manufacturing economy – which, it is hoped, can stay a step ahead of competitors overseas.
Based at Edinburgh’s Heriot-Watt University, which has a world-renowned engineering department, the Engineering and Physical Sciences Research Council centre for innovative manufacturing in laser-based production processes is researching a diverse range of technologies. The centre, which is supported by £5.6 million from the research council, and almost £5 million from 31 manufacturing industry partners, is intended to help British companies to take advantage of these advances, bringing together a multidisciplinary team of researchers and partners. The centre’s director, Professor Duncan Hand, says lasers are an “enabling technology” for manufacturing, feeding into many areas of engineering. Firms involved in the industry in the UK include those making high-power lasers for manufacturing, and those integrating those lasers into machine tools.
But there is a field where British firms have made less use of the technology than other countries, says Hand. “The area we have not done so well in is making use of these lasers for manufacturing in the UK. Our laser companies tend to export 99% of what they make. We are keen to support UK manufacturing with laser technology,” he says.
One area that uses lasers is additive layer manufacturing (ALM) processes, especially those producing metal components. About 40% of the Edinburgh laser centre’s work is devoted to ALM, says Hand. In terms of traditional metal-cutting or welding, penetration of laser technology in the British market is “not particularly high,” he adds. “There are companies that use lasers for cutting metal sheet and welcome them in terms of their flexibility in terms of changes of design, which involves changes to software, rather than hardware. There is take-up of lasers but it is not as big at home as in the Far East. Germany has made more use of lasers than the UK, too.”
Laser technology offers several benefits. It can allow firms with high labour costs to compete more effectively with overseas rivals, says Hand. Another advantage is that lasers for welding create welds with a lower total heat input, he adds. “You end up with less heat-affected material than if you were using, say, an arc welding process.”
Another important area is laser marking, as used in creating date-stamping for food packaging, and even for patterning genes. “Laser marking can give you a pretty indelible mark on lots of different materials,” says Hand. According to leading British engineering firm Renishaw, every one of its products involves a laser at some stage, whether in terms of high-precision marking for quality and traceability, or for other parts of the manufacturing process.
High precision laser machines are used by metrology firm Renishaw
Lasers can be used to cut both brittle and softer materials more effectively, says Hand. But the speed and financial benefits vary depending on application. Glass for mobile phones can be cut effectively using lasers. If a soft material is difficult to cut mechanically because of deformation, lasers can be used. The effectiveness of using lasers to cut standard materials depends on quantity, and the quality desired for the cut. “They are not the answer to everything,” says Hand. Lasers are cheaper and more reliable than they were, but “they are a relatively expensive part of a piece of equipment,” he says.
The laser centre at Edinburgh is funded for the next four years, but Hand says the university has been researching these techniques for some time. “We have been looking at the development and application of high-power lasers in manufacturing for 20 years.”
Hand is also working on a separate project with the University of Bath on delivery of high-peak-power lasers down optical fibres. High-peak-power lasers take the energy in a longer pulse and ‘squash’ it into a short pulse of a few picoseconds. This approach has benefits for machining material, making it “almost like a cold machining process,” he says. “That makes it very clean, and the optical fibres make it possible to deliver the laser in a flexible way. You can move the fibre around in the most flexible manner possible.”
Meanwhile, additional laser manufacturing progress is being made in Cambridge, where engineering firm TWI is one of six laser research institutes involved in a Europe-funded suite of projects to accelerate the development of laser-based equipment and “encourage the adoption of lasers in manufacturing operations” across the Continent.
Fibre provider: New forms of laser increase manufacturing efficiency
Lashare, as the scheme is known, or Sharing Laser Expertise for the Benefit of SMEs, is funded under the EU’s seventh Framework programme, which is also extensively used by organisations such as Leicestershire’s engineering and research consultancy Pera to fund British engineering projects.
Choon Yen Kong, a laser specialist at TWI, says: “Lashare is a complex project that involves a lot of parties and research and development in Europe. Lashare is assessing the latest laser technologies, and within the programme we are looking at cutting and welding.”
The scheme began in September 2013 and should help to spread new laser-based manufacturing techniques, providing a robust framework for the assessment of laser equipment and technologies. These range from individual components such as the laser source, to more customised or specialised machine tools for a given manufacturing application.
Lashare comprises 14 laser equipment studies. TWI is involved in one of these, known as Nextcut, which is examining the use of a high-power direct-diode laser for metal-cutting applications. The assessment is validating benefits, such as increased productivity and reduced costs, by producing and integrating a diode laser source with a CNC flatbed system for cutting; carrying out an experimental matrix of cutting trials; and performing validation of the equipment in a production-style environment.
Light circuit: Lasers are used during the manufacture of PCBs TWI has been involved in the development of laser processing since the 1960s, and has experience in many aspects of the technology, including surface transformation hardening, micro-joining to additive manufacturing, and thick-section welding and specialist cutting. Further projects are expected to be introduced under the Lashare umbrella in the future, says Kong.
As with Hand, he believes that laser technology will ultimately allow British firms to compete more effectively with manufacturers overseas, such as in the Far East. “In the UK, we are looking to such technologies for advanced manufacturing. They will burnish our cutting edge,” he says. “We are using lasers to improve efficiency, so we can complete manufacturing processes in shorter time and use less energy. Lasers are more efficient than conventional arc welding: lasers can weld wind-turbine components, for example, in days rather than weeks.” These are important developments given the relatively high cost of labour in Britain, he says.
Further breakthroughs are likely to occur in using lasers to weld very thick material or to join different materials together, according to TWI. “For example, we are looking at using electron beam welding to weld very thick sections of 120-150mm steel in one part, using lasers in the region of 20-30mm,” says Kong. “Also, there are advances to be made in joining different types of material – such as welding copper with steel.”
Most laser cutting in the UK is carried out by carbon dioxide lasers, which have an efficiency of about 8%, he says. But other techniques are becoming available, says Kong. “Through Lashare, we are introducing technology such as fibre lasers and diode lasers. They will increase efficiency to about 35-40%, and help to save energy.”
Indeed, fibre laser cutting machine tool sales are increasing in the UK as an alternative to traditional CO2 laser-based cutting equipment, says Dave Larcombe, managing director of Coventry laser cutting tool firm Bystronic, which is Swiss-owned.
For processing thin materials, including stainless steel, fibre machines can be between two and three times faster than conventional CO2 systems, he says. “They also use about a third of the power from the wall.” In the UK, the company sold more than 50 fibre laser cutting machines in 2014, compared with 14 of the rival CO2 laser systems.
The fibre laser machines are imported from Bystronic’s European parent. “We introduced the technology in 2011, starting off with a 2kW version, and we are up to 6kW now.” The benefits are principally felt when cutting thin materials. On thicker materials the cutting speed is similar to that of CO2, says Larcombe.
Reflective materials can also be cut by fibre laser without damaging the window that stops reflections going into the light source. When cutting copper, brass and aluminium, a pool of molten metal can act like a mirror. Fibre technology prevents this from happening, and damage to the laser occurring.
On a true fibre machine, the laser light is generated by banks of LEDs. The fibre optic cable is spliced into the light, amplifies it, and directs it down to the material. In a conventional CO2 laser, the light is shone via a series of mirrors which have to be very precisely aligned. “These mirrors degrade and get dirtier over time, and they are expensive. They can mean a lot of servicing in terms of cleaning and replacing them,” says Larcombe. With the fibre-
optic cable, there is no need for this alignment, so the machines need to be serviced every 3,000 hours, compared with every 2,000 hours for CO2. “There is less to do, so the servicing is half the price,” he says.
Sales of fibre laser machines are likely to increase, he believes. There are advantages that CO2 systems will continue to offer. “These include a better surface finish when cutting large amounts of thick material,” he says. Users can expect to pay a 5% premium for fibre laser machines.
He sees the introduction of fibre laser cutting as a manufacturing milestone. “Every so often a disruptive technology comes along that causes a paradigm shift in manufacturing. Additive manufacturing, or 3D printing, has been one example in recent years. It is increasingly clear that fibre laser cutting is rapidly becoming another.”
Pooling expertise Europe-wide Lashare is the acronym for a European project involving more than 30 small and medium-sized enterprises from across the Continent, partners from industry, and six renowned laser research institutes. The project’s main objective is to share knowledge on laser-based equipment and its use. “As a key success factor for European manufacturing, the transfer of innovative solutions from the laboratory into industrially robust products stands at the heart of the project,” it says.
Lashare is co-funded by the European Commission, and coordinated by the Fraunhofer Institute for Laser Technology (ILT), based in Aachen, Germany. With 420 employees and more than 11,000m2 of research space, the Fraunhofer ILT is a globally recognised contract research institute. Its activities cover a wide range of areas, such as the development of new laser beam sources and components, precise laser-based metrology, testing technology and industrial laser processes. These processes
include laser cutting, caving, drilling, welding and soldering, as well as surface treatment, micro-processing and rapid manufacturing.
The Fraunhofer ILT is part of the Fraunhofer-Gesellschaft – the model for the Catapult centres introduced by the British government on the recommendation of technology entrepreneur Hermann Hauser. The Fraunhofer-Gesellschaft has 67 institutes and
23,000 staff. Since September 2013, Lashare has initiated 14 projects, the first results from which are now being made available. And the venture is expanding: a competitive call this month will allow new teams of suppliers and users developing laser technology for manufacturing to join Lashare.
The organisation intends to now focus on sensors and knowledge-based ICT systems for complex manufacturing tasks using lasers. Through this latest call, funding of more than 1.7 million euros is being offered to new partners, based on the rules of the Framework programme of the commission. The new Lashare projects are expected to start in September.