Forschungshighlights des Fraunhofer IWS

Flexible additive manufacturing of functional components

Additive manufacturing is going to revolutionize manufacturing technology. Today’s limitations in components’ and tools’ manufacturing can be overcome by the three-dimensional layered deposition of material. This process permits maximal freedom of design and enables the designdriven production of complex functional products. Printed turbines and control cabinets, dental and function-integrated implants, generated satellite and aircraft components will all become reality. This will open up entire new worlds of manufacture – tool-free, fast and economical.

Together with their partners, the consortium AGENT3D is getting ready for lift-off in the coming years: Additive manufacturing will be a key technology, providing companies with competitive advantages.

Links

• Additive Manufacturing Center Dresden (AMCD)
• Additive Manufacturing and Surface Technology
  

Milestones in battery research

For about five years Fraunhofer IWS researchers have been working on the development of suitable electrode materials and manufacturing processes to produce high energy density battery cells based on lithium-sulfur technology in a cost effective manner. At the “Future Energy” conference in November 2015 researchers presented for the first time lithium-sulfur pouch cells with specific energy densities exceeding 300 Wh kg-1, which is an approximately 25 percent increase over classic lithium-ion technologies. With regard to an increasing demand for low-cost stationary energy storage, IWS researchers are also working on room temperature sodium-sulfur battery cells. Anode and cathode electrolytes were adapted so that such battery cells can now be operated at room temperature instead of 300 °C. These cells have discharge capacities of up to 980 mAh per gram of active cathode material. The charging efficiency exceeds 95 percent and the cells can be reversibly discharged and recharged more than 1000 times. The EU project “ALISE” started in June 2015 so that IWS can continue with these developments. A BMBF project “DryLIZ” was finished in 2015. Here the researchers showed ways to lower fabrication costs and to reduce processing times for cutting electrodes.

Links

• Advanced Battery Technology Center (ABTC)
• Chemical Surface Technology
  

Laser beams stamp microstructures

Surface nano- or microstructures can significantly alter the properties of components or products. Depending on the material and the specific requirements, a whole range of techniques are used to produce functional surfaces. Lasers offer great flexibility in this regard. In a bid to improve their performance in surface structuring, the research team headed by Prof. Andrés Lasagni has been using interference patterns from several laser beams. This makes it possible to generate millions to billions of microstructures in one go. For his innovative work, Prof. Lasagni was awarded second place in the Berthold Leibinger Innovation Prize 2016 together with Prof. Frank Mücklich from Saarland University.

Ideas and requests for functional surfaces abound. Next to classic applications such as the minimization of wear on lubricated surfaces, antibacterial properties are also in demand, as are implant surfaces that facilitate cell accumulation for improved grafting processes. Improvements in the efficiency of solar cells are planned. Electrical plug-in connections are also to become more reliable in the future, ensuring that loose connections will not have a negative impact on driver assistance systems or autonomous driving features.

Links
 

• Direct Laser Interference Patterning
  
• A fast, ecofriendly way of de-icing aircrafts

Diamond-like coatings save fuel

Friction is the worst enemy of engine designers because it causes wear that reduces engine life and increases fuel consumption, leading to higher operating costs and environmental pollution. A laser arc welding process co-developed by the Fraunhofer IWS in Dresden enables moving engine parts to be coated with a superhard carbon material that significantly reduces frictional wear.

Super hard ta-C coatings (Diamor®) are suitable for many industrial applications due to their excellent wear resistance and their potential to significantly reduce losses due to friction. The Laser-Arc technology developed at the IWS is unique in productivity and reproducibility. Fraunhofer IWS was awarded the 2016 EARTO Innovation Prize and the Joseph-von-Fraunhofer-Preis 2015 for this work.

Links

• Carbon Coatings
  
• EARTO Innovation Award 2016 goes to Dresden

Remote laser metal cutting

The Remote laser cutting technique is a sublimation cutting procedure, which does not need any additional cutting gas assistance. Even in the case of metal cutting, extremely high cutting velocities of up to 800 meters per minute can be reached. The Fraunhofer IWS utilizes the high laser performance of the new laser generation with brilliant beam characteristics to minimize interaction times using extremely high processing speeds. The laser beam energy causes solely the material’s vaporization in the cutting kerf.

The Remote cutting technique is a very promising alternative for cutting those components, which so far could only be manufactured by stamping procedures (e. g. motor gaskets or electrodes for lithium-ion cells). Furthermore, the procedure enables the use of high-strength steels for stamped and bent parts as well as greater freedom in constructively designing the components.

Dr. Matthias Lütke from the Fraunhofer IWS Dresden received the annual prize 2012 of the Wissenschaftlichen Gesellschaft für Lasertechnik e. V. (WLT - German Scientific Laser Society). He was honoured for the development of a Remote laser cutting technique, a procedure, which caused world-wide appreciation and sensation.

Links

• Laser Cutting

Joining in aircraft manufacturing – more efficiency by lightweight construction

For the partners in the aerospace industry as well as their suppliers, Fraunhofer IWS develops and optimizes laser welding of aluminum and titanium alloys (typical in aerospace) applying laser beam and friction stir processes as well as industrialization of large-scale and complexly shaped 3D components (primary structures).

A most essential aim for the production of airliners is reducing weight and, at the same time, production costs. Here the laser beam welding of stiffener elements in fuselage structures can contribute to a high degree. Due to the seam formation, stress and distortion, the two beam welding process takes place simultaneously and from both sides. With two unique machines for laser beam and friction stir welding we are able to join three-dimensionally big parts with filler wire using laser beam welding and with a moving clamping device.

Friction stir welding (FSW) is known for its many advantages in terms of tensile strength and damage tolerance of the joint, but also for its challenges, when welding three-dimensional contours or limp parts. Fraunhofer IWS is using novel machine concepts to overcome these restrictions. These help users to explore new design capabilities for light-weight and efficient part designs. Due to reduced machine invest costs, these concepts can furthermore reduce their investment during industrialization of the process.

Links

• Cutting and Joining
• Aerospace Technology

Artificial mini organisms instead of animal testing

The microphysiological systems developed at the Fraunhofer IWS are miniaturized cell culture systems the size of a business card, which reproduce the pharmacologically relevant functional mechanisms of the human body. As well as the distribution of substances through a network of vessels, this also includes the microphysiological environment of somatic cells and the interaction between different cell types. Thus, the biochemical and cellular procedures of the human body’s organs can be reproduced. This is necessary to replace complicated pharmaceutical tests, which currently take place through animal testing.

In specific terms, researchers are mimicking the function of the organs and organ systems through the joint cultivation of several human cell types in the microphysiological system. As in the human body, different cell types need different conditions to fulfil their specific functions. The researchers’ task at Fraunhofer IWS is to develop customized microphysiological systems for various organs on the chip, thus contributing to a reduction in animal testing. Important body functions, such as the constant regulation of temperature at 37 °degrees centigrade, are provided in all microphysiological systems using technical solutions such as heating and cooling elements. The special feature of the microphysiological systems developed at the Fraunhofer IWS is a miniaturized pump based on the human heart. Powered by a special controller, blood-like cell culture medium is circulated in the artificial capillary network, ensuring cells are cultivated at optimal levels of oxygen and nutrients. The size of the artificial capillary network can be calculated using mathematical models.

The developed microphysiological systems are used by many partners in research and industry. The applications range from individual organ structures in one microphysiological system to many organs in a “multi-organ-chip”. Together with the University Hospital Dresden the Fraunhofer IWS researchers have developed a microphysiological model of the renal capillaries. This allows important kidney disease processes to be reconstructed without using laboratory mice, thus reducing animal testing in basic research. The researchers are currently developing a complete cellular model of the kidneys.

Links

• Micro- and Biosystems Engineering
• Radioactive Substances Fight Cancer in the Mini-lab

Increasing the service life of turbine blades with laser

For more than 30 years, the IWS has been working with laser-assisted surface finishing processes to reduce the damage to turbines caused by condensed water droplets at low pressure. The water droplets destroy the turbine blades’ leading edge, which are designed for decades-long use. The result is considerable economic damage.

With laser hardening with flexible beam shaping, scientists have found a solution for Martensitic hardened steel turbine blades which also deals with the constantly changing blade geometry. The result is a significantly increased wear resistance and a significantly longer service life, thanks to a stress-reducing hardness zone expansion.

The laser-assisted procedure for localized surface layer hardening won them the 2006 Joseph-von-Fraunhofer Award. After gathering conclusive data, around 34,000 laser hardened turbine blades are now stored or in use in more than 180 power plants worldwide. The so-equipped turbine rotors have a longer lifespan and provide a higher electrical efficiency.

Links

• Power and Environmental Engineering
• Heat Treatment and Plating