Special delivery - fibre optics at AILU conference

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Fibre-coupled laser systems for welding automotive gear controllers along with a 20kW laser cell installed at the Manufacturing Technology Centre in Coventry, UK, were both discussed at AILU's Power Beam Delivery and Manipulation conference, which took place on 3 December. Tom Eddershaw reports from the event 

A fibre-coupled laser system for making the welds on automotive gear shift controllers has been developed by Erlanger Lasertechnik. Erlas developed the systems as part of a 2.5-year, €3.5 million project and has installed two machines, one in Germany and one in Hungry, with a third €1.7 million system being built in China.

Roland Dierken from Erlanger Lasertechnik outlined the project at the AILU Power Beam Delivery and Manipulation conference, which was held at the University of Cambridge on 3 December.

The Erlas system for assembling and welding gear box parts was built for the automotive industry that is ‘driving’ automated manufacture in Germany. It used robots to mount the components in a jig before being transferred into a welding room. The production process used seven robots in all, each with six-axis movement, five of which assembled the components before then passing them into one of the two welding cells. The cells used two robotic arms that provided laser movement of 190 x 320 x 70mm. It would take eight seconds to weld the 22 seams before the part is moved out for integrity checks to be made.

In all, 1 million of these gear shift controllers are made per year and so any time savings in production are crucial. Dierken commented that Erlas’ aim was to make the time required for laser processing as the primary cycle time. However, he added that the laser processing was just the tip of the iceberg and that loading and unloading parts into the robot cell was the process that took the most time.

The conference focused on beam delivery, which was a big part of the Erlas project. The Erlas system was based on a robot cell where both the laser head and the workpiece itself were moved for the laser to access each side of the part, so required a fibre-delivered laser.

Chaired by Duncan Hand, professor of applied photonics at Heriot-Watt University in Edinburgh, the event held presentations and exhibitions from a range of companies and speakers followed by a tour of Cambridge University’s Centre for Industrial Photonics Institute for Manufacturing.

Ten companies exhibited a range of mechanical devices, lasers, lenses, protective equipment and thin films for use in the photonics industry between the 11 talks that were given by speakers from both industrial and research backgrounds. The talks illustrated the imaginative ways that industry is finding to manipulate the direction of a laser across an expanding range of applications.

Tony Jones, managing director of TEC systems, used a case study of a 20kW laser cell which his company has installed in Coventry, for the Manufacturing Technology Centre to discuss beam delivery and other considerations in robot controlled fibre laser systems.

For this case study, TEC systems decided to use a six-axis robotic arm with a 2.9m reach, which can move at 16m/s and carry 180kg. The system was required to have 3D movement capabilities around a product of up to 3m in diameter and be able to cut, clad, clean and weld while having four types of fibres that could be interchanged easily. The robot would require beam delivery fibres and water cooling to be accessible at the robot head. The only convenient way to provide these is to have a myriad of cables running down the arm, so as to not inconvenience the essential movement.

The robotic arm was fully automated; however, mounting of the components had to be done manually, unlike in the system that Dierken from Erlanger Lasertechnik discussed.

James Hall spoke, on behalf of Tannlin, about a new 2D kinematic actuator the company was developing. Designed for small, smooth accurate movements to fine tune the position of a laser for 2D movement, it used a single rail for the x direction with two motorised components with arms of a fixed length. When the angle between the arms decreased, the y coordinate increased; when the angle increased, the y coordinate decreased.

The machines have been built as economical, simple, and adaptable with a low moving mass to provide frictionless repeatability. They could possibly be used to provide very small, precise movements on the end of a robotic arm, Hall stated. He did concede that currently the actuator was quite slow moving with the current speed being 40mm/s.

Paul Hilton of TWI presented novel methods of high power beam delivery for nuclear decommissioning. He started by pointing out that in decommissioning requires the storing of nuclear material until it has become safe. This means space is an issue and suggests by using remote decommissioning lasers to reduce the size of the waste, more material can be stored in a smaller area.

Hilton said that cut quality is not a concern, and that the lasers TWI were suggesting could therefore use long focal lengths. Hilton showed that these lasers can cut through tubing of a diameter of 170mm and a maximum thickness of 60mm. By using a snake arm robotic manipulator from OC robotics the TWI laser can manoeuvre around obstacles, cut its way through obstructing materials and then dismantle the material, while being controlled from a safe distance. Hilton then progressed to show a ‘hand-held’ laser that could possibly be used for the same function.

Other speakers present were Beat Neuenschwander from Bern University of Applied Science, Switzerland, who discussed the results of a study that used polygon scanners at different speeds and analysed the changes in accuracy. Stephen Brüning spoke on the uses of picoseconds lasers for manufacturing printing tools, while Mark Greenwood discussed how his company, JK Lasers, was overcoming the problems of back reflection and using them to the lasers advantage.