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17th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2017

作者： Zanjani, Matin Yahyavi Zeidler, Henning Martin, André Schubert, Andreas Prof. Micromanufacturing Technology Faculty of Mechanical Engineering Technische Universität Chemnitz Chemnitz09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz09126 Germany

ISBN: (纸本)9780995775107

In Electrochemical Machining (ECM), where the material removal takes place based on the anodic dissolution of the workpiece material, the working distance is one of the most important parameters. Especially in Jet Electrochemical Machining (Jet-ECM), where a micro nozzle is moved over the initial surface of the workpiece in order to apply an electrolytic free jet to produce the desired shapes, the distance between the nozzle and the workpiece becomes even more important. On the one hand a small working distance is aspired to achieve high current densities resulting in a high efficiency of the process. On the other hand the working distance needs to be large enough to avoid damages on the micro nozzle caused by electrical discharges or mechanical contact. Hence, the adjustment of the working gap is essential to realize a precise, effective and secure Jet-ECM process. The control of the gap size is done based on the data gathered before machining by surface measurement. Until now, the initial surface has been detected by electrostatic probing through moving the nozzle stepwise to the work piece surface and detect the voltage drop between the nozzle and the work piece. With this strategy, only a limited number of points can be detected within adequate time. Hence, in most cases only three points of the initial surface are detected in order to adjust the working distance according to the planar inclination of the workpiece. The coordinates of the three detected points are used to calculate the normal vector of the initial surface. In recent studies, another strategy was analysed, which is realized by dividing the surface into smaller areas and respectively calculating the normal vector of each area in order to obtain more accurate data of the initial surface. A further strategy is to use probing along the machining path of the tool and to gather the coordinates of a number of points along the path. The above mentioned methods usually do not ensure the precise control of

关键词： Surface analysis

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Process analysis for magnetic pulse welding of similar and dissimilar material sheet metal joints

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Procedia Engineering 2017年 207卷 353-358页

作者： Verena Psyk Christian Scheffler Maik Linnemann Dirk Landgrebe Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Strasse 88 09126 Chemnitz Germany

Magnetic pulse welding (MPW) is an impact welding technology for producing metallic bonds of similar and dissimilar materials offering advantages such as avoidance of temperature induced problems. Based on the parameters describing the collision of the joining partners, specifically the impact angle and impact velocity, so-called welding windows describe whether or not welding will be successful for a specific material combination. However, as in MPW collision parameters depend on equipment and setup dependent parameters, using these welding windows for process design requires knowledge about the adjustment of the collision parameters via the adjustable process parameters. Therefore, the influence of adjustable process parameters on collision parameters and resulting weld quality is analyzed and trends, for a target oriented process and joint design, are deduced. Specifically, joining of copper to aluminum, copper to copper, aluminum to copper and aluminum to stainless steel is regarded.

关键词： Magnetic pulse welding Process analysis Multi-material joints

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Simulation of Error-prone Continuous Generating Production Processes of Helical Gears and the Influence on the Vibration Excitation in Gear Mesh

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Procedia CIRP 2017年 62卷 256-261页

作者： Simon Kimme Ruben Bauer Welf-Guntram Drossel Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Str. 44 01187 Dresden Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenainer Str. 88 09126 Chemnitz Germany

A very important feature of high quality gears is a low noise emission in all operating conditions. Micro-geometry of the gear is of relevance for the vibration excitation in the tooth contact and significantly affected by the manufacturing process, especially the finishing operations. Besides known process related effects, uncontrolled variations such as inaccuracies in the speed synchronization of different axes or vibrations influence the surface structure of the tooth flanks. In this paper a detailed simulation of the production process is presented, providing crucial information about characteristic process properties and enabling investigations on the impact of manufacturing process on gear mesh acoustics.

关键词： simulation of gear machining defective cutting process acoustic relevant vibrations

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Designing a Flawless Hem Flange Bonding Process

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ADHESION ADHESIVES&SEALANTS 2017年第3期14卷 26-29页

作者： Wolfgang Woyke Fred Jesche Sandra Menzel Dirk Landgrebe Volkswagen AG Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Germany

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Author Correction: The influence of different sample preparation on mechanical properties of human iliotibial tract

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Scientific reports 2021年第1期11卷 2673页

作者： Benjamin Fischer Sascha Kurz Andreas Höch Stefan Schleifenbaum ZESBO - Center for Research on the Musculoskeletal System Leipzig University Semmelweisstraße 14 04103 Leipzig Germany. Benjamin.fischer@zesbo.de. Department of Orthopedic Trauma and Plastic Surgery Spine Center Leipzig University Leipzig Germany. Benjamin.fischer@zesbo.de. ZESBO - Center for Research on the Musculoskeletal System Leipzig University Semmelweisstraße 14 04103 Leipzig Germany. Department of Orthopedic Trauma and Plastic Surgery Spine Center Leipzig University Leipzig Germany. Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz Germany.

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Different encapsulation strategies for implanted electronics

Different encapsulation strategies for implanted electronics

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作者： Winkler, Sebastian Edelmann, Jan Welsch, Christine Ruff, Roman Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 Chemnitz09126 Germany Fraunhofer Institute for Biomedical Engineering IBMT Ensheimer Strasse 48 66386 St. Ingbert Germany

Recent advancements in implant technology include increasing application of electronic systems in the human body. Hermetic encapsulation of electronic components is necessary, specific implant functions and body environments must be considered. Additional functions such as wireless communication systems require specialized technical solutions for the encapsulation. In this paper 3 different implant strategies based on the material groups silicone, ceramics and titanium alloys are evaluated. With the background of a specific application the requirements for the encapsulation are defined and include the implementation of electrical feedthroughs, wireless communication and wireless energy transfer as well as biomedical specifications such as hermetic sealing, mechanical stability and biocompatibility. The encapsulations are manufactured and qualified experimentally. © 2017 Sebastian Winkler et al., Published by De Gruyter.

关键词： Silicones

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Polypropylene based piezo ceramic compounds for micro injection molded sensors 21st

Polypropylene based piezo ceramic compounds for micro inject...

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21st Symposium on Composites, 2017

作者： Doerffel, Christoph Decker, Ricardo Heinrich, Michael Tröltzsch, Jürgen Spieler, Mirko Nendel, Wolfgang Kroll, Lothar Institute of Lightweight Structures Chemnitz University of Technology ChemnitzD-09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 ChemnitzD-09126 Germany

ISBN: (纸本)9783035711981

Polymer matrix compounds based on piezo ceramic and electrically conducting particles within a thermoplastic matrix show distinctive piezoelectric and dielectric effects which can used for sensor applications. The electrical and mechanical properties can be adjusted in a wide range by varying the ratio of active filling particles and the matrix materials. The sensor effect of the compound is generated by the ceramic particles. A large ratio of piezo ceramic powder facilitates a high sensitivity. The electrical permittivity of the otherwise insulating matrix polymer can be adjusted by the amount of conductive filler. An aligned permittivity leads to a stronger electrical field in the ceramic particles. In contrast, too many conductive particles create a conductive network in the compound which short-circuits the sensors. The piezo ceramic compounds can be processed via micro injection molding for application as ceramic sensors. This offers a wide range of new sensor design variants, notably three-dimensional and highly complex geometries. However, there are two main demands for a highly sensitive sensor, which are conflicting. On the one hand the filler content of piezo ceramic particles in combination with electrical conductive carbon nanotubes must be very high;on the other hand the wall thickness should be as thin as possible. For filling cavities with a high aspect-ratio in an injection molding process, low viscosity polymer melts are necessary. These process characteristics conflict with the increasing viscosity by filling the melt with the particles. The sensor measuring area has to be designed as thin walled as possible. In order to overcome this obstacle a dynamically tempered mold design is applied to avoid solidification of the melt, before the mold is completely filled. The mold can be tempered by Peltier elements. The fully electric tempering is cleaner, more precise and more reliable than conventional water or oil tempering. © 2017 Trans Tech Publication

关键词： Molds

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Hot forming of large spur gears

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Procedia Engineering 2017年 207卷 615-620页

作者： Dirk Landgrebe Andreas Sterzing Mike Lahl Matthias Milbrandt Anne Manuela Taubert Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 Chemnitz 09126 Germany

forming processes are generally characterized by a high degree of material utilization as well as short process times and, consequently, a decent economic efficiency. Considering their application in the manufacturing of large spur gears, forming processes offer a significantly attractive characteristic for the production of essential gearing components commonly used in wind turbines or marine engines. Furthermore, the hot forming process can be defined as an incremental forming process which enables the use of relatively low forming forces and results in a more compact design of the used machines. These conveniences are utilized in terms of roll forming with round tools to form gears and threads in a competitive way. Based on experiences gained over many years of researching rolling technologies, a cross-rolling process characterized by round tools with outer gearings was elaborated to realize a hot forming process for gear rolling of large spur gears at the fraunhofer IWU Chemnitz. Based on the already researched forming of smaller dimensioned gears, rolling trials utilizing a new hot-forming machinery - including defined inductive heating process before rolling - to realize large gears with outer diameters of up to 1000 millimeters were conducted. In terms of realizing this ambition, the derivation of the designated machine parameters for rolling large gears in real-life dimensions can be defined as a crucial factor. Consequently, the experimental research was followed by a mathematical analyzation of the forming forces, momenta as well as the necessary steps to determine the best possible scaling factors for the work pieces.

关键词： Hot forming gear rolling large gears bulk metal forming resource efficiency

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CAD-integrated modelling of Lattice structures for additive manufacturing and property evaluation of generated specimens

CAD-integrated modelling of Lattice structures for additive ...

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Materials Science and technology Conference and Exhibition 2017, MS and T 2017

作者： Kordass, R. Koch, P. Toeppel, T. Korn, H. Schoene, C. Mueller, B. Stelzer, R. Fraunhofer Institute for Machine Tools and Forming Technology IWU Noethnitzer Str. 44 Dresden01187 Germany Technical University of Dresden Institute of Machine Elements and Machine Design George-Baehr-Strasse 3c Dresden01069 Germany

ISBN: (纸本)9781510850583

Lattice structures are highly recommended as lightweight components. But until now, parts with lattice structures are mainly used for illustrative purposes. This is because their modelling, dimensioning, and build preparation still remains complex. To simplify this process a CAD-integrated tool is developed. Therein, lattice structures are represented on a parametric level. In the design process the topology of the whole structure as well as single lattice elements can be customized individually. It enables the designer to create fully adapted load carrying components and finally results in lightweight parts, less powder consumption, faster build time, and therefore lower costs during manufacturing. The mechanical properties of the structure are automatically computed by means of FEM. For verification of the mechanical property predictions, tensile tests are performed with Ti-6Al-4V and X3NiCoMoTi18-9-5 steel lattice structures following the design suggestions in draft standard DIN 50099. © Copyright 2017 MS&T17®.

关键词： Poisson ratio

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Application of Substructure Techniques to Predict Cutting Stability for Mobile machine tools

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Procedia CIRP 2017年 58卷 110-115页

作者： Hendrik Rentzsch Martin Kolouch Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

Mobile machining solutions use autonomous machining units that can be transported to different part locations, making possible easy maintenance and repair of large industrial equipment. Every new part and location results in different boundary conditions for the mobile machine tool-part system; influencing the dynamics of the combined system and necessitating different strategies for part/machine referencing and clamping. To facilitate efficient mutability and modularity in mobile machining solutions, this paper presents a dynamic substructuring strategy that combines the response characteristics of the mobile machine unit with different base models to obtain the synthesized mobile machine tool dynamic response. Numerical and experimental verification of the approach is provided. Framework presented can also combine measured response of parts for which models may not be available a priori. Methods presented provide experimental guidelines for establishing strategies for planning of machining strategies based on the evaluated dynamics.

关键词： Dynamics machine tool Chatter Substructuring

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