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54th CIRP Conference on Manufacturing Ssystems, CMS 2021

作者： Frye, Maik Mohren, Johannes Schmitt, Robert H. Fraunhofer Institute for Production Technology IPT Steinbachstraße 17 Aachen52074 Germany Laboratory for Machine Tools WZL RWTH Aachen University Cluster Production Engineering 3A 540 Aachen52074 Germany

The application of machine learning (ML) is becoming increasingly common in production. However, many ML-projects in production fail due to poor data quality. To increase the quality, data needs to be preprocessed. Hundreds of methods exist for data preprocessing (DPP) that are selected manually depending on use-case requirements. For these reasons, DPP is currently performed unstructured and accounts for 80 % of ML-projects' duration. Thus, we introduce a structured DPP-approach, in which DPP-methods are recommended based on production use-case requirements by benchmarking identified DPP-methods according to ML-model performance on five data sets. The approach is validated through two new use-cases. © 2021 Elsevier B.V.. All rights reserved.

关键词： machine learning

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High performance machining of continuous metal fibers with cascaded multi-stage profile tools 9

High performance machining of continuous metal fibers with c...

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9th CIRP Conference on High Performance Cutting, HPC 2020

作者： Teicher, Uwe Lange, Tristan Ihlenfeldt, Steffen Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden01187 Germany Technische Universität Dresden Institute of Manufacturing Technology Dresden01062 Germany Technische Universität Dresden Institute of Mechatronic Engineering Dresden01062 Germany

ISBN: (纸本)9781713835431

Metallic fibers are essential for applications in the chemical industry, the automotive industry for brake pads and, more recently, for the air conditioning modules. The most productive process to date for producing continuous fiber lines with fiber cross-sections between 50 and 150 µm is the application of cascaded multi-stage profile tools for cutting from semi-finished wire products. One challenge is the development of a technology for highly ductile materials made of aluminium, which are used as fiber materials in the area of refrigeration adsorbers. Preliminary studies have shown that high cutting speeds are necessary for machining. For this reason, a highly manually operated machine system was advanced to meet the requirements of high cutting speeds and to integrate a process monitoring system. For the first time, experimental investigations were able to show the interrelationships between set technology values and the effective machining forces for this process. Further investigations were done using the example of aluminium alloys 5019 for an analysis of a control system for wire breakage detection on the basis of force sensors. © 2020 The Authors. Published by Elsevier B.V.

关键词： Automotive industry

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Working gap analysis in electrochemical precision machining of external geometries with ring cathodes

Working gap analysis in electrochemical precision machining ...

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20th CIRP Conference on Electro Physical and Chemical Machining, ISEM 2020

作者： Schaarschmidt, Ingo Hackert-Oschätzchen, Matthias Meichsner, Gunnar Steinert, Philipp Zinecker, Mike Schubert, Andreas Micromanufacturing Technology Chemnitz University of Technology Chemnitz09107 Germany Manufacturing Technology with Focus Machining Otto von Guericke University Magdeburg Magdeburg39106 Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz09126 Germany

Pulsed electrochemical machining (PECM) with oscillating cathode is a non-conventional manufacturing technology to machine complex precision geometries independent from the mechanical properties of the workpiece material. PECM with oscillating cathode is an advanced development of conventional ECM by applying a pulsed electric current in conjunction with an oscillating movement of the cathode. Result is electrochemical precision machining with a more stable process combined with better accuracy and quality. This work focuses on the analysis of the resulting side working gap in electrochemical precision machining of external geometries by applying PECM. Therefore, the height of a ring cathode was varied to adjust the cathode inner surface. The resulting side working gap was studied through multiscale multiphysics simulation applying COMSOL Multiphysics as well as experiments applying a PEMCenter 8000. As main result, the increase of the resulting side working gap as consequence of an increasing cathode inner surface will be analysed in detail. © 2020 The Authors. Published by Elsevier B.V.

关键词： Cathodes

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Automated design of product-flexible car body fixtures with software-supported part alignment using particle swarm optimization

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Procedia CIRP 2020年 88卷 157-162页

作者： Rayk Fritzsche Eric Voigt Robert Schaffrath Marcel Todtermuschke Marcel Röber Head of group Assembly systems at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz 09126 Germany Scientific employee at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz 09126 Germany Head of dep. Assembly systems at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz 09126 Germany

The fraunhofer IWU has been developed specialized clamping robots for production of different car-models on one fixture. As a base for the fixture design, a method for optimal part alignment has been developed. For handling multitude of possibilities regarding the alignment of parts from different car-models, a specific software tool using particle swarm optimization has been created. The objective was to achieve similar travels for all clamping robots in this fixture. To facilitate the integration of the automated part alignment into fixture design, a further software tool for automatically designing a flexible fixture was modelled.

关键词： Body in white Automated device design Particle swarm optimization Product flexibility

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A comprehensive and interdisciplinary perspective on sustainable manufacturing towards sustainable life cycles

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Procedia Manufacturing 2020年 43卷 383-390页

作者： Marion Früchtl Miriam Leis Rafael Wertheim Fraunhofer-Gesellschaft Munich 80686 Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz 09126 Germany / Braude Karmiel Israel

For achieving sustainable manufacturing it may not be enough to only focus on manufacturing processes, systems and products as separate entities for optimization, but it may require analyzing and engineering their broader and possibly unobvious interconnections. Whereas new technologies can play a significant role in resource efficiency, sustainability improvement and life cycle engineering, other factors like consumer behavior, global cost structures and even geopolitical issues play an important role for achieving sustainable manufacturing and sustainable life cycle development. This requires interdisciplinary research and analysis approaches. Concepts like Socio-Technical Systems (STS), Life Cycle Analysis (LCA) and systems engineering can help uncover the multiple impacting factors to be considered in comprehensive sustainability analysis and engineering.

关键词： Sustainability manufacturing Socio-Technical Systems Life Cycle Analysis Biological Transformation interdisciplinarity

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Data-driven decision support system enabling the circularity of products

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Procedia CIRP 2024年 130卷 1499-1504页

作者： A.-S. Wilde M. Juraschek Christoph Herrmann Institute of Machine Tools and Production Technology Chair of Sustainable Manufacturing and Life Cycle Engineering Technische Universität Braunschweig Langer Kamp 19b 38106 Braunschweig Germany Open Hybrid LabFactory e.V. Herrmann-Münch-Straße 2 38440 Wolfsburg Germany Fraunhofer Institute of Surface Engineering and Thin Films Riedenkamp 2 38108 Braunschweig Germany

Implementing a Circular Economy (CE) is one approach to reach a higher level of sustainability for products. The individual product’s circularity and the resulting choice of the best fitting life cycle path are influenced for instance by varying product properties due to stochastic influences of processes or during use, developments in the availability of (re-)process techniques and prospective changes in regulatory constraints. To support the product circularity by selecting the most sustainable path and decide for instance to reuse, remanufacture or recycle, an evaluation of the potentially available strategies is necessary when planning the life cycle of circular products as well as for improving the circularity of each individual product in the use stage. For this, gathering, processing and analyzing product-specific data, such as initial product properties, intensity of use and external influences, is a key element. Against this background, a framework and procedure model for the implementation of a data-based decision support system to evaluate and assess possible life cycle strategies is proposed. With this, recommendations for selecting and designing the most sustainable life cycle path depending on specific target functions can be derived.

关键词： Circular Economy data-driven approach decision support

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Design and validation of a suction device to reduce cross-contamination in multi-material laser-based powder bed fusion

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Procedia CIRP 2023年 120卷 380-385页

作者： Thomas Bareth Niklas Fromm Timo Schroeder Jan-Philipp Fuerstenau Max Horn Christian Seidel Fraunhofer IGCV (Fraunhofer Institute for Casting Composite and Processing Technology IGCV) Am Technologiezentrum 10 86159 Augsburg Germany Munich University of Applied Sciences Department of Applied Sciences and Mechatronics Lothstr. 34 80335 Munich Germany CADFEM GmbH Pelikanstr. 13 30177 Hannover Germany Technical University of Munich Institute for Machine Tools and Industrial Management Boltzmannstr. 15 85748 Garching Germany

Powder suction modules for additive manufacturing systems in the field of multi-material laser powder bed fusion (PBF-LB/M) have a critical influence on the quality of the manufactured components. In particular, metal powder cross-contamination originating from insufficient removal of foreign particles during multi-material processing can lead to undesired changes in material properties. In this paper, a suction device was simulated, designed, and validated to reduce cross-contamination. Requirements and necessary characteristic values of the multi-material PBF-LB/M system, the powder suction module, and the materials used were determined. Furthermore, an iterative simulative method and procedure for the design of suction devices was applied. For this purpose, a flattened bell-shaped geometry with flow-optimized fins was presented. This design led to both a high flow velocity and a homogenous velocity distribution at the nozzle inlet for full-surface multi-material PBF-LB/M suction modules. The developed method was validated by applying it to the material combination of tool steel 1.2709 and copper alloy CW106C. The aim was to reduce the cross-contamination generated during the in-process on an SLM 280 HL multi-material PBF-LB/M system. Multi-material samples were built using the original nozzle design as well as the newly developed improved powder suction module and investigated in terms of resulting cross-contamination using energy-dispersive X-ray spectroscopy. The improved suction module had a significantly higher flow velocity and a more homogenous velocity distribution at the nozzle inlet compared to the original suction module. Cross-contamination of the manufactured multi-material samples was reduced by up to 93 % due to the improved suction model.

关键词： metal additive manufacturing laser powder bed fusion laser beam melting multi-material PBF-LB/M

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Single point incremental forming of large sheet metal components

Single point incremental forming of large sheet metal compon...

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ASME 2019 International Mechanical Engineering Congress and Exposition, IMECE 2019

作者： Schieck, Frank Mauermann, Reinhard Weise, Dieter Demmler, Matthias Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Saxony Germany

ISBN: (纸本)9780791859377

The production of complex, large-scale cladding parts made of metal in small quantities for a wide range of applications in architecture, power generation, shipbuilding, but also rail vehicle construction, mobile work machines and, last but not least, automotive sector is a major challenge in terms of principled manufacturability, but also in terms of manufacturing costs. Appropriate components are often produced in small quantities by hand, whereby the reproducibility and achievable quality depend largely on the experience and craftsmanship of the employer. The incremental forming using CNC-controlled machine tools or robots offers a good alternative for an efficient and reproducible production of sheet metal components with batch size one. There are already a large number of research work, studies and examples of applications worldwide regarding principled incremental forming strategies, process layout, FE simulation and optimization strategies. The fraunhofer IWU works with the claim of applied research, that is, to transfer results from basic research into an industrial application. This also applies to the field of incremental sheet metal forming. Especially in the area of large-scale, 3-dimensional components, there is a very great need on the part of the industry. The paper provides an overview of current research results in the field of incremental forming of industrially relevant large-scale structures up to dimensions of approximately 4 x 2 meters, which are carried out in the single point process on a modified large milling machine. The topic of shape storage (molds), flexible clamping frames and heating equipment for temperature-supporting incremental forming of light metals is also addressed. The outlook identifies application and development potential aimed at both the further development of the technology and the associated equipment technology. Copyright © 2019 ASME.

关键词： machine tools

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Gathering of Process Data through Numerical Simulation for the Application of machine Learning Prognosis Algorithms

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Procedia Manufacturing 2020年 47卷 608-614页

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

In recent years, FEA simulation of forming processes has increasingly developed as a good alternative to complex experimental work in the determination of process parameters and product properties. However, detailed material data (e.g. flow curves) are necessary for the execution of FEA simulations, which are often not available to manufacturers and users in the early stages of the product development. In this paper, a method is shown by which application it is possible, that only on the basis the general mechanical properties (e.g. tensile strength, sheet thickness) and the use of data-based prognosis models of supervised machine learning to predict directly a result regarding suitable process parameters as well as expected forming result properties. Thereby an extensive technological database was generated for the joining by forming process self-pierce riveting (SPR) by means of numerical simulation. Subsequently, different learning algorithms are trained using these numerical data and their prediction quality is compared.

关键词： machine Learning forming Simulation Self-pierce riveting

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Monitoring the Evolution of Dimensional Accuracy and Product Properties in Property-Controlled forming Processes

SSRN

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SSRN 2023年

作者： Stebner, Sophie Charlotte Martschin, Juri Arian, Bahman Dietrich, Stefan Feistle, Martin Hütter, Sebastian Lafarge, Rémi Laue, Robert Li, Xinyiang Schulte, Christopher Spies, Daniel Thein, Ferdinand Wendler, Frank Wrobel, Malte Vasquez, Julian Rozo Dölz, Michael Münstermann, Sebastian Integrity of Materials and Structures RWTH Aachen University Aachen Germany Institute of Forming Technology and Lightweight Components Dortmund University Dortmund Germany Forming and Machining Technology Paderborn University Paderborn Germany Institute for Applied Materials - Material Science Karlsruhe Institute of Technology Karlsruhe Germany Fraunhofer Institute for Casting Composite and Processing Technology Garching Germany Institute of Materials and Joining Technology Otto-von-Guericke University Magdeburg Germany Forming and Machining Processes Technische Universität Dresden Dresden Germany Institute for Machine Tools and Productions Processes Virtual Production Engineering Chemnitz University of Technology Chemnitz Germany Institute of Metal Forming RWTH Aachen University Aachen Germany Institute of Automatic Control RWTH Aachen University Aachen Germany Institute for Production Engineering and Forming Machines Technical University of Darmstadt Darmstadt Germany Institut für Geometrie und Praktische Mathematik RWTH Aachen University Aachen Germany Measurement and Sensor Technology Chemnitz University of Technology Chemnitz Germany Digital Process Engineering Group Institute for Mechanical Process Engineering and Mechanics Karlsruhe Institute of Technology Karlsruhe Germany Materials Test Engineering Dortmund University Dortmund Germany

As recent trends in manufacturing engineering disciplines show a clear development in the sustainable as well as economically efficient design of forming processes, monitoring techniques have been gaining in relevance. In terms of monitoring of product properties, most processes are currently open-loop controlled, entailing that the microstructure evolution, which determines the final product properties, is not considered. However, a closed-loop control that can adjust and manipulate the process actuators according to the required product properties of the component will lead to a considerable increase in efficiency of the processes regarding resources and will decrease postproduction of the component. For most forming processes, one set of component dimensions will result in a certain set of product properties. However, to successfully establish closed-loop property controls for the processes, a systematic understanding of the reciprocity of the dimensions after forming and final product properties must be established. This work investigates the evolution of dimensional accuracy as well as product properties for a series of forming processes that utilize different degrees of freedom for process control. © 2023, The Authors. All rights reserved.

关键词： Process control

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