Kempten, Germany—From experience Sauer Lasertec has learned that the output of a company's machinery is limited as soon as it has filled the capacity of its production facility.

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Small-sized productive drilling machine

Kempten, Germany—From experience Sauer Lasertec has learned that the output of a company's machinery is limited as soon as it has filled the capacity of its production facility. Numerous surveys have shown that the footprint of a machine is an important factor for companies. Those who cannot afford larger facilities depend on smaller machines. Because of this experience the company developed the Lasertec 50 PowerDrill with a footprint of only 43 ft2 and stability provided by a solid polymer concrete base. With this new system, which was introduced at a recent open house here, the company expects to reach a wider range of smaller companies who will appreciate the advanced machine design and lower purchase price of a smaller machine that does not reduce productivity.

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Lasertec's PowerDrill series has been designed specifically for laser drilling of aero engine components such as turbine blades, vanes, shrouds, heat shields, and similar parts. This concept is supported by a special software that is easy to program and user friendly. The productivity of the PowerDrill technology has already been proven by the larger machines in the series. New optics enable focus size change without moving the focus spot in any direction. This machine can be equipped with Nd:YAG, CO2, or fiber laser sources and it can reach accuracies of 0.0003 in.

While the Lasertec 50 is much smaller than its bigger sisters, the access to the working chamber still is large enough for the industry's needs, measuring 19.7 in on the X- and Y-axes and 27.6 in on the Z-axis. Workpieces can have a weight of up to 31 lbs. Thanks to linear drives with an acceleration of 1g workpieces can be processed at travel speeds over 2,300 in/min.

Sauer Lasertec (www.gildemeister.com) will offer the new machine in a PowerDrill version and as a PowerShape machine, so it can be used for the process of diffuser laser ablation for shaped holes.

Laser beam repairs engine components

Aachen, Germany—A key strategy to ensure flight safety is to maintain reliable engine performance, which is why engines undergo regular, thorough inspections. Engine components that are made from titanium and nickel-based alloys (superalloys) are subject to heavy wear due to extreme fluctuations in pressure and temperature, and they can be damaged by foreign bodies that are sucked into the engine during take-off and landing. Until recently, it was not a feasible option to repair and replace sections of worn materials, necessitating replacement of the entire component. This process is extremely expensive and replacements are often difficult to get hold of due to material availability problems in the global market.

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Repairing a turbine engine component (Fraunhofer ILT).
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Researchers from the Fraunhofer Institute for Laser Technology (ILT) and RWTH Aachen Chair for Laser Technology (LLT) have overcome these difficulties by using a laser cladding technique that enables these defective engine components to be repaired. “What is so innovative is the fact that we can take oxidation-sensitive titanium materials and components that have a tendency to distort and weld them in a precise and reproducible manner without any distortion,” explains Dr. Andres Gasser, project manager at the Fraunhofer ILT. “A local gas atmosphere is used to prevent the molten weld pool generated in the cladding process from reacting with the surrounding atmosphere. With this method we can avoid the need to use a costly processing gas chamber.” The Aachen-based research institute is able to take on responsibility for handling the entire project, ranging from process development and certification to installation of a system for laser cladding at the site of the industrial project partner.

Using this new technique, a local weld pool is generated by the laser beam on the surface of the component. A specially designed powder feed nozzle then introduces a metal powder composed of a similar material. The resulting layer possesses similar mechanical properties to those of the component. “One of the keys to this technique is a newly developed system of powder feed nozzles, which increases the efficiency of powder use while preventing oxidation of the layers,” explains Gerhard Backes, project manager for nozzle development at the LLT. A further advantage of laser cladding in comparison to conventional welding is the fact that the low thermal load helps to minimize component distortion while ensuring that the weld is free from defects and smoothly contoured to the shape of the component.

In parallel to developing the process, the Fraunhofer ILT supplied a modified TRUMPF laser cladding machine, which has been running at Rolls-Royce Deutschland (RRD-Oberursel) for around one year, where it has been producing superb results. Martin Spallek, who is responsible for component repair at RRD, sums up the developments, “By deploying this repair technique we have managed to reduce the time required for general overhauls of the engines by approximately one-third while simultaneously cutting costs. That has made a huge contribution towards boosting our competitive advantage.”

For further information on this advanced laser process contact: andres.gasser@ilt.fraunhofer.de or gerhard.backes@ilt.fraunhofer.de.

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