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Fundamental research of applying tungsten carbide-cobalt as tool electrode material for sinking EDM

Procedia CIRP 2020年 95卷 466-470页

作者： Eckart Uhlmann Mitchel Polte Robert Bolz Julian Börnstein Fraunhofer Institute for Production Systems and Design Technology Pascalstrasse 8-9 Berlin 10587 Germany Technische Universität Berlin Chair of Machine Tools and Manufacturing Technology Pascalstrasse 8-9 Berlin 10587 Germany

The manufacturing process milling is limited in machining specific geometries like inner contours with sharp edges, high aspect ratios or defined radii. Sinking EDM (S-EDM) is an appropriate process to machine complex features if the negative geometry is machinable. The tool electrode wear is a critical factor, because it affects machining accuracy and process efficiency. The tool electrode wear depends on S-EDM processing parameters, the geometry and material of the tool electrode. The material tungsten carbide-cobalt owns suitable thermophysical properties for the application as tool electrode material in EDM. Most applications of tungsten carbide-cobalt in EDM are limited to EDM drilling processes, where tungsten carbide tube electrodes are widely used. The advancements in milling of hard materials enable an economic manufacturing of tungsten carbide-cobalt form electrodes for sinking EDM applications. However, it is not investigated which composition of the material tungsten carbide-cobalt is the most appropriate for the application as tool electrode material in S-EDM. Additionally, there are no suitable EDM process parameters in order to benefit from the material characteristics of the respective tungsten carbide-cobalt. Focus of this work is the analysis of different tungsten carbide grades regarding the average grain size and the cobalt content in order to identify correlations between the material characteristics and the EDM process results. Therefore, eight different tungsten carbide grades with four different grain sizes and five different cobalt contents were applied in S-EDM experimental analysis. The experimental studies showed a general suitability of tungsten carbide-cobalt tool electrodes for EDM-processing, where the material removal rate is comparable to commonly used tool electrode materials. Nevertheless, the relative tool wear shows inferior results. It could be observed that higher cobalt content and coarser grain size of the applied tungsten c

关键词： EDM tungsten carbide-cobalt tool electrode

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A two-step digitalization level assessment approach for manufacturing companies

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Procedia Manufacturing 2021年 54卷 25-30页

作者： Günther Schuh Thomas Scheuer Gábor Nick Ádám Szaller Tamás Várgedő Laboratory for Machine Tools and Production Engineering (WZL) RWTH Aachen University Aachen 52074 Germany Fraunhofer Institute for Production Technology Aachen 52074 Germany Széchenyi University Research Center of Vehicle Industry Győr 9026 Hungary EPIC InnoLabs Ltd. Budapest 1111 Hungary Institute for Computer Science and Control Budapest 1111 Hungary Department of Manufacturing Science and Engineering Budapest University of Technology and Economics Budapest 1111 Hungary

Manufacturing companies are facing the fourth industrial revolution, which concerns itself with the real-time data-based communication and connection between cyber-physical systems and people. To initiate a successful digital transformation, many organizations turn to Industry 4.0 maturity models for orientation and advice. This paper aims to enable companies to find the model that suits them best. Therefore, several existing models are introduced and two of them, a quick-assessment model ( CCMS ) and a more extensive approach ( Industry 4.0 Maturity Index ), are described in detail. These two complementing models are combined into a new resource-efficient approach to assessing Industry 4.0 maturity.

关键词： Industry 4.0 Maturity model Readiness assessment Digitalization

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Modelling of surface formation mechanism during burnishing of aluminium

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Procedia CIRP 2019年 82卷 450-454页

作者： Rico Stöckmann Matthias Putz Technische Universität Chemnitz Institute for Machine Tools and Production Processes Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 09126 Chemnitz Germany

Burnishing is a finishing process which levels the roughness of machined surfaces and increases the hardness by micro-forming. In this paper, a novel two-dimensional finite element model for the diamond ball burnishing process on aluminium is presented, which allows a prediction of the surface structure. The force, step over distance, and tool geometry during the burnishing process are taken into account by the model and the results are verified by experimental investigations. The verification shows that the model is able to predict all geometrical surface aspects like roughness, sinking-in and bulge formation for reasonable process parameters.

关键词： Finite element method (FEM) Surface modification Burnishing

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Kinematics of the Lumbo-Pelvic Complex under Different Loading Conditions

Kinematics of the Lumbo-Pelvic Complex under Different Loadi...

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作者： Weidling, Martin Voigt, Christian Wendler, Toni Heilemann, Martin Werner, Michael Jarvers, Jan-Sven Heyde, Christoph-E. Faculty of Medicine University of Leipzig Semmelweisstrasse 14 Leipzig Germany Faculty of Medicine University of Leipzig Leipzig Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden Germany Department of Orthopaedic Trauma and Plastic Surgery University Hospital Leipzig Leipzig Germany

The lumbo-pelvic complex is a highly complex structural system. The current investigation aims to identify the kinematics between interacting bone segments under different loading conditions. A specimen of the lumbo-pelvic complex was obtained from a human body donor and tested in a self-developed test rig. The experimental setup was designed to imitate extension, flexion, right and left lateral bending and axial rotation to the left and to the right, respectively. The vertebra L3 was firmly embedded and load was introduced via hip joints. Using a digital image correlation (DIC) system, the 3D motions of 15 markers at different landmarks were measured for each loadcase under cyclic loading. For each loadcase, the kinematics were analyzed in terms of three-dimensional relative movements between L3 and the sacrum. The usefulness of the experimental technique was demonstrated. It may serve for further biomechanical investigations of relative motion of sacroiliac and vertebral joints and deformation of bony structures. © 2019 by Walter de Gruyter Berlin/Boston.

关键词： Kinematics

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Process data based Anomaly detection in distributed energy generation using Neural Networks

Process data based Anomaly detection in distributed energy g...

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International Conference on Control, Automation and Diagnosis (ICCAD)

作者： Max Klein Gregor Thiele Adalbert Fono Niloufar Khorsandi David Schade Jörg Krüger Fraunhofer Institute for Production Systems and Design Technology IPK Berlin Germany AUCOTEAM GmbH Berlin Germany Institute for Machine Tools and Factory Management Technical University of Berlin Berlin Germany

ISBN: (数字)9781728169996

ISBN: (纸本)9781728170008

The increasing share of renewable energies in the total energy supply includes a growing number of small, decentralized energy generation which also provides control energy. These decentralized stations are usually combined to a virtual power plant which takes over the monitoring and control of the individual participants via an Internet connection. This high degree of automation and the large number of frequently changing subscribers creates new challenges in terms of detecting anomalies. Quickly adaptable, variable and reliable methods of anomaly detection are required. This paper compares two approaches using Neural Networks (NN) with respect to their ability to detect anomalous behavior in real process data of a combined heat and power plant. In order to include process dynamics, one approach includes specifically engineered features, while the other approach uses Long-Short-Term-Memory (LSTM). Both approaches are able to detect rudimentary anomalies. For more demanding anomalies, the respective strengths and weaknesses of the two approaches become apparent.

关键词： Power generation Artificial neural networks Computer architecture Monitoring Anomaly detection Generators Time series analysis

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Identification of Indicators for the Assessment of Technological Risks within technology Selection

Identification of Indicators for the Assessment of Technolog...

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International Scientific Conference on Information technology and Management Science of Riga Technical University (ITMS)

作者： Gunther Schuh Patrick Scholz Stefan Seichter Chair of Production Engineering Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University Aachen Germany Fraunhofer Institute for Production Technology IPT Aachen Germany

ISBN: (数字)9781728191058

ISBN: (纸本)9781728191065

An accelerated technological change combined with shortened technology development- and life-cycles results in additional pressure on technology-oriented companies in global competition. These companies are compelled to make decisions for new technologies at an early stage to secure existing and gain new competitive advantages. The challenge is to make the right technology decisions considering the existing high uncertainty at this stage. Hence, existing risks must be assessed concerning the forecast potential to become manageable for decision-making processes. While existing approaches for the assessment of new technologies are primarily focused on technology potentials, holistic approaches for risk assessment of technologies are missing. In particular, there is a lack of the required assessment basis indicating the technological risk. To establish a valid basis for such a technology risk assessment and to support companies in technology selection at an early stage, this paper provides a set of risk factors as indicators for the assessment of technological risks. The identification of these risk factors is based on an extensive literature review. Using a systematic procedure, 83 publications were identified and 697 possible factors were initially compiled. Finally, 19 risk factors were derived based on quantitative and qualitative analyses, which provides the foundation for assessing the technological risks of new technologies. The procedure as well as the identified risk factors are presented in this paper.

关键词： Companies Risk management Uncertainty Systematics Technological innovation ISO Standards Bibliographies

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Nondestructive testing of composite fibre materials with hyperspectral imaging : Evaluative studies in the EU H2020 FibreEUse project

arXiv

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arXiv 2021年

作者： Yan, Yijun Ren, Jinchang Zhao, Huan Windmill, James F.C. Ijomah, Winifred de Wit, Jesper von Freeden, Justus National Subsea Centre Robert Gordon University Aberdeen United Kingdom Dept. of Electronic and Electrical Engineering University of Strathclyde Glasgow United Kingdom Dept of Design Manufacturing & Engineering Management University of Strathclyde Glasgow United Kingdom INVENT GmbH Christian-Pommer-Straße 47 Braunschweig38112 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Hermann-Münch-Str. 1 Wolfsburg38440 Germany

Through capturing spectral data from a wide frequency range along with the spatial information, hyperspectral imaging (HSI) can detect minor differences in terms of temperature, moisture and chemical composition. Therefore, HSI has been successfully applied in various applications, including remote sensing for security and defense, precision agriculture for vegetation and crop monitoring, food/drink, and pharmaceuticals quality control. However, for condition monitoring and damage detection in carbon fibre reinforced polymer (CFRP), the use of HSI is a relatively untouched area, as existing non-destructive testing (NDT) techniques focus mainly on delivering information about physical integrity of structures but not on material composition. To this end, HSI can provide a unique way to tackle this challenge. In this paper, with the use of a near-infrared HSI camera, applications of HSI for the non-destructive inspection of CFRP products are introduced, taking the EU H2020 FibreEUse project as the background. Technical challenges and solutions on three case studies are presented in detail, including adhesive residues detection, surface damage detection and Cobot based automated inspection. Experimental results have fully demonstrated the great potential of HSI and related vision techniques for NDT of CFRP, especially the potential to satisfy the industrial manufacturing environment. © 2021, CC BY.

关键词： Nondestructive examination

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Case Study for the Integrated Development of a Modular System for Vehicle Superstructures of Battery Electric Light Commercial Vehicles

Case Study for the Integrated Development of a Modular Syste...

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IEEE International Conference on Industrial Engineering and Engineering Management

作者： G. Schuh C. Dölle R. Kreutzer M. Patzwald J. Koch Chair of Production Engineering Laboratory for Machine Tools and Production Engineering (WZL) RWTH Aachen University Aachen Germany Fraunhofer Institute for Production Technology IPT Aachen Germany

ISBN: (数字)9781538672204

ISBN: (纸本)9781538672211

Considering fossil fuel scarcity, future transportation is a core challenge for industry and society. With increasing urbanization, the issue of emission-free transportation is of particular relevance for metropolitan areas. To reduce pollution, environmental zones have been set up in numerous German cities. These affect small and medium-sized companies (SMEs) that operate within the city centers, but whose logistics are diesel-based. At the same time, battery electric light commercial vehicles (BELCVs) are more expensive than diesel vehicles. Apart from component costs, this is partly due to lower volumes and limited economies of scale. In the context of vehicle structures in BELCVs, new possibilities for installation space design arise. This paper aims to modularize this installation space tailored to SMEs' needs. Since purchasing is the primary cost driver for SMEs, the presented case study pursues the goal of realizing "car-sharing" for BELCVs via modularization, so that capital investments can be distributed among several parties. Thus, the objectives of the present paper are sharing the lessons learned of the case study and contributing to the validation of the modular system design methodology used.

关键词： Urban areas Interviews Batteries Sustainable development Space vehicles Industries Economies of scale

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Minimally-invasive lag screw fixation technique for posterior malleolus fractures: A cadaveric study

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Foot & Ankle Surgery: Techniques, Reports & Cases 2024年第2期4卷 100385-100385页

作者： Fullarton, M., MSc Vidakovic, H., FRACS Kieser, D.C., PhD, FRACS Hammer, N., PhD Wyatt, M.C., MD, FRACS University of Otago Department of Anatomy Dunedin New Zealand University of Otago Department of Orthopaedics and Musculoskeletal Medicine Christchurch New Zealand Medical University of Graz Division of Macroscopic and Clinical Anatomy Gottfried Schatz Research Center Graz Austria Department of Trauma Orthopedic and Plastic Surgery University Hospital of Leipzig Germany Fraunhofer Institute for Machine Tools and Forming Technology Division of Biomechatronics Dresden Germany College of Health Massey University New Zealand

AbstractAnatomical reduction and lag screw fixation of posterior malleolar (PM) ankle fractures typically involves an open posterolateral approach. The aim of this anatomical study was to assess whether a minimally-invasive, percutaneous posterior-to-anterior lag screw fixation technique is safe to perform. Eighteen cadaveric ankle specimens were used. A transverse incision was made at the lateral border of the Tendo Achilles (TA). Windows were made lateral to and through the substance of the TA and simulated reduction and placement of a single lag screw performed. Specimens were then fully dissected to ascertain proximity and damage to anatomical structures. Lag screw fixation was placed appropriately in all ankles. No injury to the neurovascular structures, ankle joint or syndesmotic ligaments was observed. The mean distance from the soft tissue window to sural nerve was 10.0 mm (range 5–16), and 9.5 mm to short saphenous vein (4–14). Whilst the muscle belly of flexor hallucis longus (FHL) was pierced in six specimens, no injuries to the FHL tendon were observed. The mean distance from screw to syndesmosis was 9.3 mm (range 3–15) and 12.7 mm to the ankle joint (7–17). This study demonstrates that posterior percutaneous lag screw fixation is both safe and accurate. Further work is required to evaluate the precision of reduction and the biomechanical stability of this fixation technique. This novel minimally-invasive technique may be beneficial in avoiding the wound complications associated with open posterolateral ankle approaches and also offer a functional advantage due to minimal soft tissue disruption.

关键词： Ankle joint Approach Fixation Posterior malleolus fracture Trauma V

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Influence of contaminants on part quality during Laser-Based Powder Bed Fusion of nickel base alloys 11

Influence of contaminants on part quality during Laser-Based...

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11th CIRP Conference on Photonic Technologies, LANE 2020

作者： Palm, Mathias S. Horn, Max Bachmann, Andreas Schlick, Georg Zaeh, Michael F. Reinhart, Gunther Institute for Machine Tools and Industrial Management of Technical University of Munich Boltzmannstr. 15 Garching b. München85748 Germany ArianeGroup GmbH Robert-Koch-Straße 1 Taufkirchen82024 Germany Fraunhofer Research Institution for Casting Composite and Processing Technology IGCV Am Technologiezentrum 10 Augsburg86159 Germany

Laser-based Powder Bed Fusion (LPBF) has become a key Additive Manufacturing (AM) technology for the production of complex metallic components within a short lead-time. Contaminated powder feedstock is a major challenge in LPBF due to the uncertain influence of contaminations on part quality. This study investigates the effects of different contaminants inside the feedstock on material density and metallurgical structure in order to evaluate their implications for serial production. Pieces of rubber gloves, human, and recoater brush hair as well as five more substances were applied manually at a defined layer during the manufacturing process of Hastelloy® X (HX) specimens. The part densities were 99.9% for all contaminated specimens. Cross-sections did not show increased porosity. For some contaminants, inclusions of foreign material residue were observed. The results for HX were evaluated and implications for comparable materials were derived. Lastly, the criticality of the investigated contaminants on part quality was analyzed. © 2020 The Authors. Published by Elsevier B.V.

关键词： Contamination

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