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Process optimization for flexible self-pierce riveting of multi-material structures

AIP Conference Proceedings 2019年第1期2113卷

作者： Tobias Falk Mathias Jäckel 1Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 01187 Dresden Germany

One of the most important mechanical joining technologies for mixed-material car body constructions is self-pierce riveting with semi-tubular rivet (SPR-ST). In order to achieve appropriate joint quality for SPR-ST, it is often necessary to use individual process parameters like die geometry or rivet length for each material and thickness combination. In this paper a method is presented, that allows to increase the flexibility of the SPR-ST process by an optimization of process parameters in regard to join several material combinations with one die geometry. Thereby FEM simulation is combined with statistical approaches to develop an optimized SPR-ST process.

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A New Systematic Approach to the Description of Processes and their Classification

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Procedia Manufacturing 2017年 8卷 199-206页

作者： Alexandr, P. Kuznetsov Hans-Joachim, Koriath Moscow State University of Technology “STANKIN” Moscow 127055 Russian Federation Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz 09126 Germany

Technical systems change their states and relations between elements during the transformation of energy, matter and information. Paper develops a new systematic approach to the description of processes and their classification, completed by a general description of systems. Systemic transformation categories of typical processes are proposed and applied for an energetic-informational model. Functional relations between categories, transformations and parameters of processes are developed for their classification and digital evaluation. The number of processes that may be formed by the elements of the system is determined by the number of combinations. The proposed general energy-information model of manufacturing processes and new classification will initiate progressive research and development activities on manufacturing processes and associated technologies, the evaluation of increased technological competitiveness, the strategic trend scouting, the optimization of manufacturing processes. © 2017 The Authors

关键词： energy information machine manufacturing matter process

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Technologies for the mechanical joining of aluminum die castings

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AIP Conference Proceedings 2019年第1期2113卷

作者： Thomas Grimm Mathias Jäckel Tobias Falk Welf-Guntram Drossel 1Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 01187 Dresden Germany

This paper shows a comparison of existing self-pierce riveting technologies with the newly developed self-pierce riveting with solid formable rivet (SPR-SF) for the joining of Aluminum die casts. The challenges during the mechanical joining of the Aluminum die cast AlSi9Mn by different joining technologies like self-pierce riveting with semi-tubular rivet (SPR-ST), self-pierce riveting with moveable die element and semi-tubular rivet (S-SPR-ST), self-pierce riveting with solid rivet (SPR-S) and self-pierce riveting with solid formable rivet (SPR-SF) will be discussed and the joining technologies in regard to process force, interlock, shear tensile strength and top tensile strength will be analyzed.

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Implementing thermomechanical properties of 22MnB5 steel during hot single-point incremental forming 5th

Implementing thermomechanical properties of 22MnB5 steel dur...

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5th International Conference on Material Science and Engineering technology, ICMSET 2016

作者： Al-Obaidi, Amar Kräusel, Verena Landgrebe, Dirk Institute of Machine Tools and Production Processes IWP Technische Universität Chemnitz Chemnitz Germany Fraunhofer-Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

ISBN: (纸本)9783035710281

The strategy in manufacturing hardened parts used in car bodies is to tailor the mechanical properties. This is done by combining together a high-strength region and a hightoughness region to ensure the crash performance required. Other successive secondary operations such as trimming, joining and welding can be improved as a result of the tailoring process. In this work, the mechanical properties of 22MnB5 alloy sheet material produced by single-point incremental forming have been tailored. For this purpose, the sheets were locally heated by induction during the forming process and subsequently cooled. The sheet temperature was controlled by the CNC milling machine feed rate and induction power. As a result, the produced tailored parts consist of three different regions: ductile, transition and hardened regions. The Vickers hardness values were 583 HV1 and 175 HV1 for the hardened and ductile regions, respectively. The proposed application allows forming and quenching at the same time without transfer and to reduce the process time. © 2017 Trans Tech Publications, Switzerland.

关键词： Induction heating

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On the correlation of hammer-peened surfaces and process, material and geometry parameters

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IOP Conference Series: Materials Science and Engineering 2019年第1期480卷

作者： S Pfeiffer M Fiedler T Bergelt M Kolouch M Putz M F-X Wagner Technische Universität Chemnitz Chair of Materials Science Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

Hammer-peening can replace extensive hand-polishing during the processing of freeform surfaces, but it is rarely applied in practice due to the interplay of numerous parameters, including the process and tool parameters as well as the geometry and the material of the workpiece. In the present study we systematically investigate the effect of tool radii, tool angles, pressure, path and impact distance and the path definition (with respect to the direction of previous surface milling) on the resulting surface roughness and strain hardening of a cast iron, a low- and a high-alloyed steel using a pneumatic tool setup and complementary Finite Element (FE) simulations. Our experimental results show that an impact and path distance of 0.18 mm, a pressure of 7.3 bar and a tool radius of 8 mm reduce the surface roughness of a face-milled surface with an average roughness of Ra = 0.8 μm to an average roughness of Ra = 0.5 μm for all materials under consideration. The FE simulations indicate that, for a ball-milled surface, the surface roughness Ra decreases (and the arithmetical mean height Sa increases) the most for a tool angle of 45° and for a hammer-peening path perpendicular to the previous ball-milling path. These results contribute to the development of a mathematical model that allows to identify suitable parameter combinations prior to hammer-peening processing for a given workpiece surface.

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E-beam sterilization of microstructures in titanium surfaces for medical implants 17

E-beam sterilization of microstructures in titanium surfaces...

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

作者： Winkler, Sebastian Dietze, Marleen Edelmann, Jan Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Fraunhofer Institute for Organic Electronics Electron Beam and Plasma Technology FEP Dresden Germany

ISBN: (纸本)9780995775107

Due to its biocompatibility titanium is the metal of choice for most medical implants. The surface in contact with the human body may be equipped with a functional microstructure for various purposes such as bone ingrowth. All implants must be sterilized before operation. Among other processes, the sterilization by low energy electron beam (e-beam-sterilization) offers a lot of advantages. The non-thermal sterilization works with short process times (milliseconds) and without microbicide gases. The radiation sterilization is a regulated process according to DIN EN ISO 11137, which describes a killing effect of microorganism after the validation of a dose of 25 kGy. In principal it is possible to sterilize all material classes, electronic devices and different geometries, so that the low energy e-beam-sterilization is a suitable method for multifunctional implants. The sterilization of surface microstructures with low energy e-beam-sterilization is challenging because of the limited penetration depth. The influence of high aspect ratio microstructures on low energy e-beam-sterilization was investigated experimentally. A microhole array with 230 μm hole diameter served as a model structure and was manufactured in the titanium surface by electrical discharge machining. Other surface microstructures were generated by laser machining and blasting. All samples were contaminated with 107 CFU/sample Escherichia coli (E. coli) K12, sterilized by e-beam and incubated in a culture medium in order to prove that the sterilization was successful. The microhole depth was varied to determine the critical depth for low energy e-beam-sterilization.

关键词： Sterilization (cleaning)

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Considering Energy-Related Factors in the Simulation of Logistics Systems

Considering Energy-Related Factors in the Simulation of Logi...

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Simulation Winter Conference

作者： Moritz Poeting Bastian Prell Markus Rabe Tobias Uhlig Sigrid Wenzel Institute of Transport Logistics TU Dortmund University Dortmund GERMANY Department Factory of the Future Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz GERMANY Department IT in Production and Logistics TU Dortmund University Dortmund GERMANY Department of Computer Science Universität der Bundeswehr München Neubiberg GERMANY Department of Organization of Production and Factory Planning University of Kassel Kassel GERMANY

ISBN: (数字)9781728132839

ISBN: (纸本)9781728120522

Traditionally, aspects such as emissions and energy consumption have to be taken into account for environmental and economic reasons when it comes to transport. In other areas of logistics, such as production logistics and intralogistics, the energy aspect is also becoming increasingly important. Existing literature has been recently reviewed in a contribution of the Arbeitsgemeinschaft Simulation (ASIM) to the Winter Simulation Conference 2018 (Uhlig et al. 2018) to develop a map of common approaches and best practices for manufacturing and logistics systems. In the paper presented here, as a complement we are focusing on the application of energy simulation in logistics to give a comprehensive overview and present exemplary case studies. Furthermore, we show a classification of approaches to combine energy aspects with simulation. Finally, we will discuss open questions and future trends in this field of research.

关键词： tools Mathematical model Supply chains Matlab Adaptation models

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Requirements and Tasks for Active Energy Management Systems in Automotive Industry

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Procedia Manufacturing 2017年 8卷 175-182页

作者： Franz, Enrico Erler, Felix Langer, Tino Schlegel, Andreas Stoldt, Johannes Richter, Mark Putz, Matthias Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 Chemnitz 09126 Germany ACOD GmbH Schillerstraße 5 Leipzig 04109 Germany

The “2020 climate and energy package” enacted by the EU aims to reduce emission of greenhouse gases, to increase the share of renewable energy and to improve overall energy efficiency. These goals are forwarded to the industry using regulations or funding opportunities. Taking a deeper look e.g. into automotive industry the companies reflect these goals to their plants across Europe. Energy efficiency is a plant-related KPI to gain customer satisfaction, enhance greener production and optimise internal costs. Current developments especially deal with base load reduction for production plants. In order to achieve this, all resources within the factory, interconnected by processes or by energy flows, have to be actively managed. This paper deals with the requirements on energy management systems stemming from the task to control production, infrastructure as well as technical building systems (TBS) simultaneously with focus on specifics of the automotive industry. © 2017

关键词： automotive energy management system energy storage management flexibility production planing and control

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Investigation of various graphene fillers for improving properties of thermoplastic polymers 17

Investigation of various graphene fillers for improving prop...

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

作者： Edelmann, Jan Albrecht, Mirko Zeidler, Henning Gehde, Michael Schubert, Andreas Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Chemnitz University of Technology Plastics Chemnitz Germany Chemnitz University of Technology Micromanufacturing Technology Chemnitz Germany

ISBN: (纸本)9780995775107

The application of graphene in polymers and polymer-based composites was investigated in an application-oriented research project. The aim was the improvement of mechanical, electrical and thermal properties by using graphene as nanofiller in the polymer matrix. Research concentrated on developing appropriate formulations of graphene-based plastics for functionally integrated components, which can be processed in an industrial environment. Since most of recent studies have been done in lab environment, guaranteeing ideal processing conditions not relevant in industrial production, the approach of this project was hallmarked by using industrial equipment for compounding and further processing.

关键词： Graphene

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Finite element simulations on the relation of microstructural characteristics and the formation of different types of adiabatic shear bands in a β-titanium alloy

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IOP Conference Series: Materials Science and Engineering 2019年第1期480卷

作者： S Winter S Pfeiffer T Bergelt M F-X Wagner Institute of Materials Science and Engineering Materials Science Group Chemnitz University of Technology 09125 Chemnitz Germany now at Fraunhofer Institute for Machine Tools and Forming Technology IWU 09126 Chemnitz Germany

Deformation at high strain rates in combination with local thermal softening can lead to the formation of so-called adiabatic shear bands. These shear bands occur when the macroscopic deformation is concentrated in microscopic areas. The fundamental thermomechanical processes and micromechanical mechanisms acting during adiabatic shear band formation are not fully understood yet. In particular, the influence of different initial microstructures on shear band formation has not sufficiently clarified. In an earlier investigation, adiabatic shear bands formed in a β-titanium alloy with different initial microstructures were characterized in detail. It was shown that different volume fractions of the α-phase result in the formation of different types of shear bands. In the present study, a simple modeling approach based on the finite element (FE) method is used to investigate in a systematic parameter study (with a special focus on mechanical and thermal variables) how these different types of adiabatic shear bands can occur in the same material. The FE simulations clearly show that microstructural characteristics – such as size and volume fraction of the α-phase in the β-titanium alloy – have a strong influence on shear band formation. This study contributes to a more detailed understanding of the microstructural and thermomechanical mechanisms leading to the formation of different types of adiabatic shear bands in titanium alloys.

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