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Intrinsic manufacture of hollow thermoplastic composite/metal structures

AIP Conference Proceedings 2016年第1期1769卷

作者： Daniel Barfuss Raik Grützner Christian Garthaus Maik Gude Roland Müller Dirk Langrebe 1Technische Universität Dresden Institute of Lightweight Engineering and Polymer Technology Germany 2Fraunhofer-Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

In contrast to common and classical joining technologies for composite/metal hybrid structures such as bonding and riveting, profile and contour joints offer a promising potential for novel lightweight hybrid structures. First and foremost, joining systems with a form closure function enable to pass very high loads into rod- and tube-shaped fibre reinforced structures and achieve high degrees of material utilization for the composite part. This paper demonstrates the theoretical and technological principals for a resource efficient design and production of highly loaded thermoplastic composite profile structures with integrated metallic load introduction elements and a multi scale form closure. The hybrid structures are produced in an integral blow moulding process in which a braided tape-preform is simultaneously consolidated and formed into the metallic load introduction element. These metallic load introduction elements are manufactured in a two-stage process of external and internal hydroforming, after forming simulations have assured process stability for consistent quality.

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Energy-sensitive control strategies for decoupled production systems

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International Journal of Sustainable Manufacturing 2014年第3期3卷 250-268页

作者： Putz, Matthias Schlegel, Andreas Stoldt, Johannes Franz, Enrico Langer, Tino Division Production Management Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

Rising demand for energy caused by emerging economies, decreasing oil stocks, and the intended nuclear phase-out in some industrial countries has led to new problems concerning sufficient and on time energy supply. Since availability of energy has a dramatic influence on production, energy has to be considered a process prerequisite instead of a production-related overhead topic, as usually done. Prospective considerations in MES and ERP systems will need to treat energy as a limited resource just like machine capacity and time. Hence, both products and processes will compete for energy. This paper discusses selected production control tasks, methods, and strategies for discrete part manufacturing. It aims at identifying the extent to which energy features can be implemented next to established logistic goals. Based on first research activities, new approaches were derived in order to develop tools for an energy-sensitive production control focusing on limited capacity of production resources. Copyright © 2014 Inderscience Enterprises Ltd.

关键词： Production control

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Challenge of machining aluminium matrix composites reinforced by diamonds 15

Challenge of machining aluminium matrix composites reinforce...

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15th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2015

作者： Schubert, Andreas Zeidler, Henning Flemmig, Sebastian Penzel, Michael Krönert, Maik Meichsner, Gunnar Essel, Shai Prof. Micromanufacturing Technology Technische Universität Chemnitz Chemnitz09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz09126 Germany Israel Institute of Metals Technion Haifa Israel

ISBN: (纸本)9780956679079

To increase the efficiency of heat transfer and cooling systems, high thermally conductive materials have to be developed. Using Aluminium reinforced by Diamond particles, thermal conductivity and heat dissipation can be enhanced in correspondence to particle size. Due to the high hardness of diamond the machinability decreases. A cutting machining process is not feasible because of the high tool wear. In this study two possible ablating techniques, Pulsed Electrochemical Machining (PECM) and Micro Electro Discharge Machining (μEDM) are assessed. It is shown that with both methods machining and shaping of AMCs, reinforced by monocrystalline diamonds, is possible. Due to the chemical stability of the diamond particles only the base material of Aluminium has been electrochemical machined. Similar to PECM, and also for μEDM, ablating is a selective machining process, but here an approach for further ablating possibilities is given. The achieved surface roughness is dependant on the particle size of the Diamond.

关键词： Thermal conductivity

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Flushing Strategies for High Performance, Efficient and Environmentally Friendly Cutting

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Procedia CIRP 2015年 26卷 361-366页

作者： P. Blau K. Busch M. Dix C. Hochmuth A. Stoll R. Wertheim Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany Technische Universität Chemnitz Institute for Machine Tools and Production Processes IWP Reichenhainer Str.70 09126 Chemnitz Germany

The rising requirements in cutting operations for higher performance and higher efficiency respecting also environmental phenomena are influencing the use of different coolants and flushing conditions. In machining difficult-to-cut materials, in particular high-temperature materials, conventional emulsion cooling is unsuitable due to the insufficient cooling effect and the energy and cost intensive equipment required. For this reason new cooling and lubricating strategies have to be developed and investigated. Using hybrid processes, mainly by superposition of various cooling strategies, offers the potential to extend the existing technological process limits of conventional cutting processes. The paper introduces theoretical, experimental and simulation results with various innovative cooling strategies, such as high-pressure cooling, cryogenic cooling and aerosol dry lubrication in grooving, turning and drilling and derives the appropriate field of application for each flushing strategy.

关键词： Cutting Coolant Flushing HPC

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Improving the ramp-up process of a body-construction line by numerical supported design of clamping devices and FEM based tolerance prognosis 18th

Improving the ramp-up process of a body-construction line by...

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18th International ESAFORM Conference on Material forming, ESAFORM 2015

作者： Landgrebe, Dirk Ackert, Patrick Grützner, Raik Weber, Johannes Mauermann, Reinhard Tegtmeier, André Fraunhofer Institute for Machine Tools and Forming Technology Nöthnitzer Straße 44 Dresden01187 Germany Porsche Leipzig GmbH Porschestraße 1 Leipzig04158 Germany

ISBN: (纸本)9783038354710

Car body manufacturing begins with sheet metal forming, while in subsequent steps the inner structures of the vehicle are assembled and connected to the outer skin by hemming. The use of FEM (finite element method) to assistant in ramp-up processes of car body construction lines is increasing, thanks to developments in recent years. Several methods to predict the distortion of joining and the dimensional effect of clamping during the assembly process were presented and validated. Dimensional effects of the clamping process are basically the result of a deliberate alignment, other than the given values of construction to compensate dimensional inaccuracy of single parts from the body shop. These deliberate alignments are generally effected through a translation of clamps and pins in the clamping device. Until now, most of the methods of clamping and joining simulation presented have been verified using academic samples. In this report, the quality of forecasting in real problems during a ramp-up process will be verified and expanded. As part of a national project, co-funded by Sächsische Aufbaubank (SAB), the potential of FEM to assist in the ramp-up process were reviewed in a cooperative effort between Porsche Leipzig GmbH and fraunhofer institute for machine tools and forming technology (iwu). Furthermore, it will be shown that developed methods are able to represent the influence of deliberate positioning of clamps in complex samples. © (2015) Trans Tech Publications, Switzerland.

关键词： Finite element method

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Dry forming of aluminium sheet metal: Influence of different types of forming tool microstructures on the coefficient of friction 18th

Dry forming of aluminium sheet metal: Influence of different...

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18th International ESAFORM Conference on Material forming, ESAFORM 2015

作者： Scholz, Peter Richard, Börner Kühn, Ralf Müller, Roland Schubert, Andreas Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 Chemnitz09126 Germany Technische Universität Chemnitz Reichenhainer Str. 70 09126 Germany

ISBN: (纸本)9783038354710

In the sheet metal forming industry lubricants are applied in forming processes to expand the technological boundaries by reducing friction and wear. The friction between tool and sheet metal is crucial to the deep drawing process. Due to economic and ecological reasons the aim of the manufacturers is to reduce or even avoid the use of lubricants. Consequently, this approach enables both a shortening of the process chains and an essential saving of resources. The advantages of structured forming tools in lubricated processes concerning the reduction of the coefficient of friction by the appearance of lubricating micro pockets are well-known. However, without using any lubricant this effect does not work. In this case the contact area is reduced by structuring the forming tool which affects the tribological system. In this paper the influence of microstructures with different geometries and surface treatments (uncoated / a-C: H: Si-coating) on the coefficient of friction in dry metal forming of the alloy AA5182 is compared to the frictional behaviour of unstructured forming tools using lubricant as reference. Before coating, the forming tools are machined by milling to generate tribologically effective microstructures. With the use of a strip drawing plant the effects of different surface microstructures and materials on the coefficient of friction are investigated. © (2015) Trans Tech Publications, Switzerland.

关键词： Lubricants

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Investigation of tribological properties of AlMg4,5Mn0,7 in a warm forming process using the barrel compression test 18th

Investigation of tribological properties of AlMg4,5Mn0,7 in ...

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18th International ESAFORM Conference on Material forming, ESAFORM 2015

作者： Müller, Benedikt Jahn, Stephan F. Fang, Ru Schubert, Andreas Technische Universität Chemnitz Reichenhainer Str. 70 Chemnitz09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 Chemnitz09126 Germany

ISBN: (纸本)9783038354710

Within the German Collaborative Research Center 39 PT-PIESA the forming of micro cavities into aluminum sheets is one challenging task. During this forming process high forces and stresses occur which lead to a high tool wear. Hence, the actually applied cold forming process should be replaced by a warm forming process. This paper shows the tribological investigations for the warm forming process. Within the experiments the barrel compression test [1] is used to determine the friction conditions by varying the size of the cylindrically shaped samples of AlMg4,5Mn0,7, the forming degree and the lubrication condition (dry, graphite, forming oil). The flat punches were made from hardened steel 1.3343. The friction factor was calculated, and surface roughness was evaluated by 3D-laser microscopy. The experiments show that the friction factor increases, especially at forming degrees below 1 and for small specimen size, compared to cold forming processes [2]. In addition to that, an influence of the lubrication condition onto the surface roughness was observed. For experiments conducted with graphite, the surface roughness is significantly higher than for samples, which were formed dryly or with forming oil. © (2015) Trans Tech Publications, Switzerland.

关键词： Graphite

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Multiphysics Simulation of the Material Removal in Jet Electrochemical Machining

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Procedia CIRP 2015年 31卷 197-202页

作者： Matthias Hackert-Oschätzchen Raphael Paul Michael Kowalick André Martin Gunnar Meichsner Andreas Schubert Professorship Micromanufacturing Technology Faculty of Mechanical Engineering Technische Universität Chemnitz D-09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 D-09126 Chemnitz Germany

Jet Electrochemical Machining (Jet-ECM) is a technology for quickly and flexibly generating micro structures and micro geometries in metallic parts independently from the material's hardness and without any thermal or mechanical impact [1] . In the process no tool wear occurs and the machined surface is very smooth [2] . The Jet-ECM process strongly depends on the shape of the electrolyte jet. In a previous study Hackert [3] built a numerical model with COMSOL Multiphysics based on a predefined jet shape. The simulated dissolution results of this model progressively differ from experimental results with increasing processing time. Hence, a multiphysics model which integrated fluid dynamics using the level set method for two-phase flow was created. Furthermore, in the present study the electric boundary resistance at the interface of workpiece and electrolyte is considered. According to the real Jet-ECM process the simulation is divided into two steps. In the first simulation step the jet is formed, and in the second simulation step the anodic dissolution is simulated by deforming the geometry. The dynamic behavior of the electrolyte jet could be simulated during the material removal process. So effects became visible which affect the machining results.

关键词： Jet Electrochemical Machining localized anodic dissolution continuous electrolytic free jet multiphysics simulation boundary resistance

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Making Sustainability Paradigms a Part of PPC

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Procedia CIRP 2015年 29卷 209-214页

作者： Matthias Putz Johannes Stoldt Christin Fanghänel Annett Bierer Andreas Schlegel Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 09126 Chemnitz Germany HTWK Leipzig – Faculty of Business Administration Gustav-Freytag-Straße 42a04277 Leipzig Germany

The mounting pressure of the European legislative to improve the sustainability of production operations prompts companies to implement sustainability paradigms into their production planning and control (PPC). First results from an ongoing European project will show how the innovative Resource Networks Methodology can be used to alter the production organisation accordingly. In particular, novel PPC strategies improving the integration of renewable energy sources and other resource efficient technologies by using previously identified levels of flexibility will be presented. These are complemented by an approach for unifying the readiness levels for application (RLA) of similar methodologies. The latter will assist decision making during the development phase and in preparation for industrial implementations.

关键词： Production planning Sustainable development Readiness levels Resource networks

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Manufacturing of micro fluidic moulds by combining micro milling and laser structuring 14

Manufacturing of micro fluidic moulds by combining micro mil...

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

作者： Schubert, A. Gross, S. Eckert, U. Edelmann, J. Fraunhofer Institute for Machine Tools and Forming Technology IWU Germany

ISBN: (纸本)9780956679031

Increasing demands regarding the functionality and the functional density of micro fluidic systems require constant miniaturisation of single components and also of the complete system. A cost efficient and effective manufacturing process requires replication processes such as injection moulding or hot embossing to structure disposables cost-effectively. This paper presents the development of the sequential process combination of laser micro structuring and micro milling for the manufacturing of micro fluidic moulds.

关键词： Injection molding

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