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Functionally Aluminum Foam Composites for Building Industry

Procedia Materials Science 2014年 4卷 133-138页

作者： Thomas Hipke Jörg Hohlfeld Susi Rybandt Department of Lightweight Design Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 09126 Chemnitz Germany

Aluminum foams already are in automotive and machine tool industry serial application. Only little interest has been shown by the construction or building industry so far. The still relatively high material costs, lack of connecting and joining techniques, as well as reservations of the users towards new material solutions are the reasons why. In the building industry design for efficiency is taking into account the principles of lightweight material and structure. Especially sandwich panels with aluminum foam core are of high interest. The high rigidity with low weight and high resistance to fire are the major advantages of these panels. Also these semi-finished materials shield electromagnetic waves and show extensive vibration reduction and sound insulation. Combining the sandwiches with additional functions such as cooling and heating by integrated tubes is one example.

关键词： Aluminum foam Foam composites Semi-finished parts Foam sandwiches Building industry Building halls.

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Integration of vision/force robot control for transporting different shaped/colored objects from moving circular conveyor

Integration of vision/force robot control for transporting d...

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International Workshop on Robot Sensing (ROSE)

作者： Michael Jokesch Mohamad Bdiwi Jozef Suchý Robot Systems Chemnitz University of Technology Chemnitz Germany Tools and Forming Technology IWU Fraunhofer Institute for Machine Chemnitz Germany Technische Universitat Chemnitz Chemnitz Sachsen DE

This paper will propose algorithms for transporting different objects from moving circular conveyor with the help of vision/force robot control. Poses and speeds of the objects are calculated from sequential images captured by 3D-camera mounted on the hand of the robot. In the conveyor there are 4 slots which contain four differently formed and coloured objects. The cross sections of these objects are the square, the rectangle, the triangle and the circle. The required object will be segmented and then recognized with the help of fast image processing algorithm depending on its colour and shape. Furthermore, this paper will improve algorithm for grasping and pulling-out the required object from slot with tight clearance. For this task two different kinds of simple force control have been developed. The objects will be grasped by a 6-DoF robot with a primitive two-finger-gripper as end-effector. In the first experiment the proposed system will follow the required object until the movement of the conveyor stops. After that it will start to pull-out the object. In more complicated case, the robot will pull-out the object while the conveyor is moving. In other words, the movement of the robot will be synchronized with the movement of the object and it should grasp it at a convenient time and pose without any prior knowledge about its velocity. This paper will be supported with real experiments presenting promising results which illustrate the capability of grasping a stuck moving object with the help of vision/force robot control.

关键词： Force Grippers Trajectory Grasping Robot kinematics Cameras

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Jet-Electrochemical machining of selective laser melted aluminum and steel alloys for micro injection moulds 14

Jet-Electrochemical machining of selective laser melted alum...

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14th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2014

作者： Schubert, Andreas Zeidler, Henning Martin, André Hackert-Oschätzchen, Matthias Kempen, Karolien Kruth, Jean-Pierre Faculty of Mechanical Engineering Technische Universität Chemnitz Chemnitz09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz09126 Germany Department of Mechanical Engineering Celestijnenlaan 300 Leuven3001 Belgium

ISBN: (纸本)9780956679031

For a flexible and resource efficient generation of moulds for micro-injection moulding, additive manufacturing processes such as Selective Laser Melting are used. Electrochemical machining (ECM) is a promising technique for the final shaping of the mould and for creation of the injection cavity with required precision, since ECM is independent of material hardness and ductility [1]. The latter property is important concerning SLM produced moulds, which are often harder and stronger than cast moulds [2]. In this study, electrochemical machining of two SLM materials, AlSi10Mg Aluminium alloy and 18Ni-300 Nickel-based maraging tool steel, is analysed. A unique process applying a continuous electrolytic free jet (Jet-ECM) is used that offers the possibility to generate micro-structures by controlling the nozzle movement and the current flow [3].

关键词： Aluminum alloys

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Closed loop control for shape memory alloy actuators

Closed loop control for shape memory alloy actuators

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IEEE SSD International Multi-Conference on Systems, Signals and Devices

作者： Christian Auerswald Björn Senf Jan Mehner Welf-Guntram Drossel Chair of Microsystems and Precision Engineering Technische Universität Chemnitz Chemnitz Germany Adaptronics and Acoustics Fraunhofer IWU Institute for Machine Tools and Forming Technology Chemnitz Germany

This paper describes design considerations of a control circuit for adaptive hybrid structures. These consist of a fiber-reinforced lightweight structure with a thermoplastic matrix and additional shape memory alloy wires, which can be used both as actuators and sensors. In order to use their properties, a control circuit able to heat the actuator wires and to measure their electrical resistance when used as a sensor is needed. In contrast to most references using expensive lab test equipment, a small sized, stand-alone control box is presented. It combines advantages of precision linear current sources for resistance measurement with high efficiency switch-mode converters delivering the wire heating current.

关键词： Heating Electrical resistance measurement Voltage measurement Resistance Optical fiber devices Matrix converters Magnetic properties

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Influence of Alloying Elements and Extrusion Process Parameter on the Recrystallization Process of Mg-Zn alloys

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Materials Today: Proceedings 2015年 2卷 S19-S25页

作者： E. Meza-García J. Bohlen S. Yi D. Letzig V. Kräusel D. Landgrebe K.U. Kainer Technische Universitaet Chemnitz Institute for Machine Tools and Production Processes Professorship Forming and Joining D-09107 Chemnitz Germany. Magnesium Innovations Center MagIC Helmholtz-Zentrum Geesthacht Max-Plank-Str. 1 D-21502 Geesthacht Germany. Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 D-09126 Chemnitz Germany

In the present work, the influence of the additions of zinc, zirconium and cerium-rich mischmetal on the microstructural recrystallization development of magnesium were investigated. Grain size and chemical composition were the principal variables of the billets used for indirect extrusion experiments. Significant changes in the evolution of the dynamic recrystallization (DRX) process as a function of the alloying element contents and the process variables were observed. Microstructures and preferred orientation of crystallites were correlated in order to discuss the role of alloy composition on the DRX. This discussion was based on the macro-texture measurements and some EBSD measurements of selected samples.

关键词： Magnesium wrought alloys zinc zirconium rare earth elements indirect extrusion recrystallisation texture

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Structural Integration of PZT Fibers in Deep Drawn Sheet Metal for Material-integrated Sensing and Actuation

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Procedia technology 2014年 15卷 658-667页

作者： M. Müller B. Müller S. Hensel M. Nestler S.F. Jahn V. Wittstock A. Schubert W.-G. Drossel Professorship for Adaptronics and Lightweight Design in Production Technische Universität Chemnitz 09107 Chemnitz Germany Professorship Micromanufacturing Technology Technische Universität Chemnitz 09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany Professorship Machine Tools and Forming Technology Technische Universität Chemnitz 09107 Chemnitz Germany

Today, adaptive sheet metal parts are manufactured by surface bonding of sensors and actuators on shaped structural parts. This paper presents a technology for direct structural integration of lead-zirconate-titanate (PZT) fibers in flat sheet metal and subsequent shaping. Microcavities are microformed into the surface of the metal sheet in which piezoceramic fibers are inserted and joined. After that, the composite is shaped by deep drawing into a complex 3D surface. The production technology is discussed in detail with regard to the limits of each process step. Functional shaped prototypes with ten interconnected parallel piezoceramic fibers were fabricated. The function as transducer and sensor for lamb waves is demonstrated and the degradation due to the shaping is compared for different parameters of the deep drawing process. The composite shapes are cups with a double curvature radius of 100 mm and 250 mm respectively. As a result, degradation of the piezoelectric function varies as a consequence of the process parameters. In the best case, a degradation of the transducer function of 33% was shown in the experiments. The cause of the decreased performance after shaping is discussed and explained by debonding mechanisms. Results of numerical simulations show good agreement with the experimental findings of the optimum process parameters.

关键词： Functional integration direct integration piezoceramic microforming microassembly deep drawing simulation function test sensor

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Mobile Augmented Reality Based Monitoring of Assembly Lines

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Procedia CIRP 2014年 23卷 246-251页

作者： Christian Kollatsch Marco Schumann Philipp Klimant Volker Wittstock Matthias Putz Institute for Machine Tools and Production Processes Technische Universität Chemnitz Reichenhainer Straße 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Straße 88 09126 Chemnitz Germany

Showing process-relevant information of assembly lines is an important task in production, e.g. for diagnostic purposes. Accessing the relevant manufacturing values during production requires extensive knowledge of the used machines and their control systems (e.g. PLC, CNC) and could cause a delay of the production process. Therefore, this paper presents an Augmented Reality (AR) based application for mobile devices realizing a user-friendly and problem-oriented visualization of relevant information directly on-site. The AR application uses a uniform graphical user interface. Due to this the user does not need to handle different human machine interfaces.

关键词： Augmented Reality Assembly Monitoring

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CAD Kernel based Simulation of Milling Processes

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Procedia CIRP 2014年 17卷 710-715页

作者： Philipp Klimant Marco Witt Michael Kuhl Institute for Machine Tools and Production Processes Technische Universität Chemnitz eichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz Reichenhainer Str. 88 09126 Chemnitz Germany

This paper describes a simulation method for NC programs. The simulation uses real axis values from a real CNC as a basis for the simulation of the generated NC program, respectively the milling strategy. To simulate the milling process by means of material removal at the virtual work piece a real CAD core was used. The CAD kernel based material removal simulation allows a close to reality simulation of the real executed NC program and enables a comparison between the simulated work piece geometry and the target CAD geometry directly in a CAD program.

关键词： CAD Kernel Simulation Milling Process

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Microstructuring of Surfaces by Two-stage Vibration-assisted Turning

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Procedia CIRP 2014年 14卷 136-141页

作者： R. Zhang P. Steinert A. Schubert Technische Universität Chemnitz Faculty of Mechanical Engineering Professorship Micromanufacturing Technology 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology 09126 Chemnitz Germany

Microstructuring is one suitable method to improve the tribological properties of surfaces. It leads to a reduction in friction and wear, especially in highly loaded tribological contacts. There are several machining techniques to generate microstructures, such as laser beam removal, cold forming, etching or fly-cutting. This paper describes a new method to produce microstructured surfaces more economically, based on a two- staged vibration-assisted turning process. During the first step, a specific microstructure is realized by ultrasonic vibration assistance of the turning tool in the direction perpendicular to the workpiece surface. In the subsequent step, the peaks of the obtained microstructured surface are removed by precision turning without vibration. This results in a plateau-shaped and microdimpled surface. The two-staged vibration- assisted turning process offers the advantage that no additional process is required after finishing because the microstructuring process is already part of the finishing operation. The investigated process can easily be integrated into large batch production, e. g., for tribological optimization of powertrain components.

关键词： Surface microstucturing Vibration-assisted turning Tribology

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Process Analysis of Water Abrasive Fine Jet Structuring of Ceramic Surfaces via Design of Experiment

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Procedia CIRP 2014年 14卷 442-447页

作者： M. Dittrich M. Dix M. Kuhl B. Palumbo F. Tagliaferri Technische Universität Chemnitz Institute for Machine Tools and Production Processes (IWP) Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany University of Naples Federico II Department of Industrial Engineering (DII) Piazzale V. Tecchio 80 80125 Naples Italy

Machining of aluminum oxide Al2O3 can be classified as challenging by reason of its brittle and high tensile material behavior. Moreover, conventional processes for machining ceramics, e.g. using laser beam or lapping, are typically associated with lower material removal rates and high manufacturing costs. Cutting using water abrasive jet enables cutting of ceramics due to exceedingly low process forces and machining temperatures. In addition to the actual cutting process, surface structuring can be carried out using a reflecting jet by a specific adjustment of process parameters. In this context, water abrasive fine jet machining is up-and-coming due to better charge and higher precision. These factors allow the insert of the smallest geometries which either cannot be manufactured by primary shaping or are suitable for manufacturing only to a limited extent. This article describes how a process design is being executed concerning productivity and machining precision by using an analysis based on the method of the Design of Experiments (DoE). The most influencing parameters become apparent, such as water pressure, abrasive flow rate or path offset. The parameters allow a specific process dimensioning in terms of material removal rate, surface roughness and depth of penetration. Furthermore the investigations show a high reproducibility of the results using appropriate process parameters. The study illustrates that the use of the water abrasive injector fine jet permits a precise and highly efficient insertion of surface structures into ceramic materials.

关键词： water abrasive jet structuring ceramic machining design of experiments (DoE) ANOVA.

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