Technology Offers Mechanical Engineering
Innovative pre-treatment optimizes service life of CVD-diamond-coated carbide tools
In a project funded by the Baden-Württemberg Stiftung gGmbH, the Fraunhofer-Institut für Werkstoffmechanik IWM has developed an improved pre-treatment process for diamond-coated carbide tools. A diffusion barrier for cobalt ensures improved adhesion of the diamond layer. The process can be applied to different carbides and enables previously unattained tool life combined with high breaking strength.
Compact ammonia-water absorption chiller with increased coefficient of performance
Scientists at the University of Stuttgart have developed an absorption chiller that is extremely compact, lightweight and stable in terms of operation, even at low evaporator temperatures and high heat rejection temperatures. Because of its compactness the absorption chiller has lower production costs and requires less refrigerant than conventional absorption chillers.
Force constant adaptation of braided sleeving in the automated production of braided components
The Institute of Aircraft Design (IFB) at the University of Stuttgart developed a flexible pressure roll mechanism for braiding machines, which significantly improves the automated braiding of components with sharp curvatures and widely varying cross-sections without the need for manual intervention. While overbraiding a mandrel the flexible mounting of the pressure rolls allows for adaptation to the mandrel's positioning (e.g. inclined position) and to changes in the cross section. They exert a constant and precisely defined force on the braid and thereby press it against the mandrel.
As part of the automated process, the robot control of the braiding machine coordinates the movement of the pressure rolls. This significantly improves the braiding of components with a variable cross-section and curvatures so that manual intervention is no longer required.
Exhaust tract for combustion engines – turbocharger
The novel MEDUSA technology for turbocharging combustion engines fits the current trend to downsize engines perfectly. The optimal inflow into the turbine, particularly at low speeds of revolution, makes the engine very responsive, with maximum torque developing in the lower range of rotatory speed. Additionally the exhaust tract that forms part of the invention is extremely robust, in particular at high combustion temperatures. Thus the technology is particularly suited for use in small gasoline engines: the efficiency is greater than for wastegate turbochargers; however, unlike the Variable Turbine Geometry (VTG) turbocharger, this charger does not require adjustable guide vanes.
Variable number of threads in braiding machines
A new embodiment of a braiding machine was developed at the Institute of Aircraft Design (IFB) of Stuttgart University. It features a thread positioning unit which forms a secondary ring of horn-gears close to the braiding point. This secondary ring moves synchronously with the primary horn-gears of the braiding machine. Therefore, the position of each thread, that is close to the mandrel, is clearly defined. This is a basic requirement for manipulation of specific threads during the braiding process, which in turn permits the automated production of components with highly varying diameters at a constant braid angle.
Lightweight design for multilayer composites with damping properties
The newly developed sheet metal composite material can be used for a wide range of applications in the automotive sector as well as in the field of mechanical engineering and manufacturing of deep-drawn part. In relation to its weight, the material possesses a high level of rigidity which can be adjusted to meet specific requirements.
The new hybrid material consists of two individual panels bonded via a viscoelastic layer, which has damping properties. Because the material has one plane outer surface paint finish can be applied and flow properties can be enhanced by adding nanostructures, for example.
Correction of angular errors in optical encoder readings prior to sensor signal generation
The purely optical compensation of errors in encoder readings allows for robust sensor design with alignment-free assembly of the encoder disc. Due to a diffractive compensation track the beam spot on the measuring track can be compensated prior to sensor signal generation.
Photo lubrication: Radiation-induced, reversible and irreversible modification of friction and adhesion
Funded by the Baden-Württemberg Stiftung gGmbH, KIT (Karlsruhe Institute of Technology) and Ulm University scientists have developed a procedure that enables the targeted modification of surfaces' friction and adhesion properties through irradiation with light. Depending on the application the modification may be irreversible, i. e. properties are adjusted once-only, or reversible, i. e. facilitating a switch between the minimum and maximum coefficient of friction in a selective and continuous manner. Therefore, the new technique opens up new opportunities for photo-activatable and photo-switchable applications even in the field of micro and nano systems technologies.
Heating control for semi-solid metal casting
An innovative procedure has been developed to control induction heating of material used for semi-solid metal casting. By analyzing electrical value and permeability of the material the grain structure can be determined during the heating process. The induction heating can be regulated accordingly so that the material retains the optimal grain structure for forming.