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Model-based framework for lean information logistics in digital production

Procedia CIRP 2023年 118卷 80-85页

作者： Frederic Meister Pascal Vogl Johannes Schilp Andrea Hohmann Rüdiger Daub Fraunhofer Institute for Casting Composite and Processing Technology IGCV Am Technologiezentrum. 10 86159 Augsburg Germany Institute for Machine Tools and Industrial Management (iwb) Technical University of Munich Boltzmannstr. 15 85748 Garching Germany

Shortening product lifecycles and intensifying individualization challenge companies to delivery products on time and to customers´ needs. To enhance efficiency in production digitization counts as mean to reach performance targets. An integrated part for achieving the logistic goals describes the effect of digital technologies on the information flow between and within processes of order fulfillment. Next to modeling information flow, key performance indicator are required for being able to retrace and quantify the effect of digital technologies. Hence, this paper describes a framework that integrates key performance indicators for information flow into a modeling approach to improve digital production processes.

关键词： Information logistics key performance indicators digital technologies BPMN 2.0

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Measuring the Amount of Plume During Laser Based Powder Bed Fusion of Metals Using Digital Image Processing

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SSRN 2024年

作者： Jacob, Adrian Kersting, Lisa Bardenhagen, Andreas Ihlenfeldt, Steffen Additive Manufacturing Materials and Technology Siemens Energy Huttenstr. 12 Berlin10553 Germany Institute of Aerospace Institute of Technology Berlin Marchstr. 12-14 Berlin10587 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Pforzheimer Str. 7a Dresden01189 Germany Institute of Mechatronic Engineering Technische Universität Dresden Helmholtzstr. 7a Dresden01069 Germany

Recent publications have put a focus on metal vaporization during the PBF-LB/M process. It is intimately connected with component defects and process by-products such as plume. Our study purposes an in-situ image processing system that aims to determine the amount of plume present in the build chamber. An algorithm isolates the plume in the images and uses a probabilistic approach to eliminate the influence of image noise and determine the amount of plume. The system is employed in the analysis of an experiment in which the scan speeds, laser power, and hatch angle were varied. In addition, the experiment includes repeated parameter sets to evaluate process stability over time. The resultant data shows a slight increase of plume generation over time, indicating a fume buildup within the AM machine’s closed build chamber. Increased laser power and scan speed result in significantly increased plume generation. The effect that the hatch angle has on plume correlates with both laser power and scan speed. © 2024, The Authors. All rights reserved.

关键词： Image processing

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Digital-supported problem solving for shopfloor steering using case-based reasoning and Bayesian networks

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Procedia CIRP 2023年 119卷 140-145页

作者： Frederic Meister Parikshit Khanal Rüdiger Daub Fraunhofer Institute for Casting Composite and Processing Technology (IGCV) Am Technologiezentrum. 10 86159 Augsburg Germany Institute for Machine Tools and Industrial Management (iwb) Technical University of Munich Boltzmannstr. 15 85748 Garching Germany

Uncertainty and incompleteness of data challenge the design of knowledge systems for problem solving in shopfloor management. The paper proposes a data-driven design that incorporates traditional means of quality management and goals of production planning and control. It integrates data of a failure mode effects analysis (FMEA) and an 8D problem-solving process into a Bayesian network (BN) embedded case-based reasoning (CBR) cycle. Reducing inconsistencies within the BN, an optimization method uses scoring schemes and structural equation modeling for learning its structure. The results suggest that the optimized BN-CBR system outperforms the single use of CBR in terms of accuracy.

关键词： Bayesian networks cased-based reasoning problem solving FMEA digital shopfloor management

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Automated porosity assessment of parts produced by Laser Powder Bed Fusion using Convolutional Neural Networks

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Procedia CIRP 2021年 104卷 1434-1439页

作者： Jan Klein Martin Jaretzki Michael Schwarzenberger Steffen Ihlenfeldt Welf-Guntram Drossel Technische Universität Dresden Chair of Machine Tools Development and Adaptive Controls 01069 Dresden Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Nöthnitzer Str. 44 01187 Dresden Germany

Laser Powder Bed Fusion (LPBF) is especially interesting for applications in industries with high quality requirements. There are different expensive and time-consuming strategies for quality assurance. A cheaper and faster approach is to analyze the data acquired during fabrication. In this work Convolutional Neural Networks (CNN) are investigated as a tool for data analysis of meltpool monitoring data. The goal is to automatically distinguish between porous and non-porous part regions. Therefore, the training data is categorized based on CT-scans of the test specimens. For increased interpretability of the results, Gradient-Weighted Class Activation Maps (Grad-CAM) are used.

关键词： Additive Manufacturing Laser Beam Melting LPBF Process Monitoring Quality Assessment Porosity In-process sensing Melt pool monitoring CNN Neural Networks

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Introducing readiness scales for effective reuse of open source hardware 32

Introducing readiness scales for effective reuse of open sou...

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32nd CIRP Design Conference, CIRP Design 2022

作者： Mies, Robert Häuer, Martin Hassan, Mehera Technische Universität Berlin Institute For Machine Tools And Factory Management Ptz 3 Pascalstr. 8-9 Berlin10587 Germany Fraunhofer Institute For Production Systems And Design Technology Digital Engineering Pascalstr. 8-9 Berlin10587 Germany

Open source hardware (OSH) describes physical products that allow for "anyone to study, modify, produce, and distribute them". While OSH principles aim to support design reuse, recent studies have challenged whether this is properly applied in practice. Therefore, this article delivers an assessment scheme that allows to identify the readiness of OSH designs for reuse. Testing the scheme on OSH ventilator designs collected by the Publnv ventilator project showed overall good usefulness of the scheme and emphasised the need of unambiguous assessment scales based on common standards. Less than two thirds of Publnv's listed projects fulfilled minimum criteria for openness. © 2022 The Authors.

关键词： Open systems

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Evolutionary optimization of deep-drawing processes on servo screw presses with freely programmable force and motion functions 54

Evolutionary optimization of deep-drawing processes on servo...

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54th CIRP Conference on Manufacturing Ssystems, CMS 2021

作者： Kriechenbauer, Sebastian Müller, Peter Mauermann, Reinhard Drossel, Welf-Guntram Fraunhofer Institute for Machine Tools and Forming Technology IWU NOthnitzer Straße 44 Dresden01187 Germany Technische Universität Chemnitz Institut für Werkzeugmaschinen und Produktionsprozesse Professur Adaptronik und Funktionsleichtbau Chemnitz09107 Germany

Servo screw presses with freely programmable force and motion functions lead to innovative forming technologies for deep drawing of sheet metals. The advanced application potential of the machine type is mainly based on the accuracy and flexibility. Due to the increase of process parameters in deep-drawing processes with variable force and motion functions, the standards for method planning (consideration of machine properties, parameterization of the movement functions) in comparison to conventional deep-drawing processes increase. The high number of parameters motivates the aim: A systematic design of deep-drawing processes with free force and motion functions on servo presses based on computational science methods. In the context of this publication, the determination of optimal parameters (force and motion functions) for a deep-drawing process with superimposed vibrations on servo screw presses will be investigated. With the help of evolutionary optimization approaches a process-design for a deep-drawing process with superposition of low-frequency oscillations will be carry out. The results of the evolutionary optimization approaches are validated by experiments with cross die part. © 2021 The Author(s).

关键词： Optimization

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Ethanol Exposure Duration Effects on Soft Tissue Biomechanics

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SSRN 2024年

作者： Werner, Michael Drossel, Welf-Guntram Löffler, Sabine Hammer, Niels Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany Institute of Anatomy University of Leipzig Leipzig Germany Division of Macroscopic and Clinical Anatomy Gottfried Schatz Research Center Medical University of Graz Graz Austria Department of Orthopedic and Trauma Surgery University of Leipzig Leipzig Germany Department of Anatomy University of Otago Dunedin New Zealand

When conducting biomechanical testing or clinical training using embalmed human soft tissues, it is essential to understand their impact on biomechanical properties and their time dependence. Previous studies have investigated this influence, but specific variations over different embalming durations have not been thoroughly addressed to ***-seven human iliotibial band specimens were obtained from nine donors. All specimens were embalmed in ethanol-glycerin for varying durations: one day, eight days, and fourteen days. Prior to the mechanical trials, the specimens underwent osmotic water adjustment, tapering and standardized clamping. Uniaxial tensile tests were conducted to determine elastic modulus, ultimate tensile strength, and ultimate strain. Surface strain measurements were performed using a digital image correlation ***-glycerin embalming of soft tissues significantly affects ultimate strain after one day of submersion time, elastic modulus after eight days, and the ultimate tensile strength after fourteen days. For applications requiring consistent and reliable material properties reflecting a (supra-)vital state, caution is advised against using embalmed tissues even following short submersion durations in ethanol-glycerin. © 2024, The Authors. All rights reserved.

关键词： Tensile strength

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Disassembly technologies for PEMFC stacks in heavy-duty applications

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Procedia CIRP 2024年 127卷 218-223页

作者： Sven Oldewurtel Arne Wagner Christoph Imdahl Sabrina Zellmer Klaus Dröder Fraunhofer Institute for Surface Engineering and Thin Films IST Riedenkamp 2 Braunschweig 38108 Germany Technische Universität Braunschweig Institute of Machine Tools and Production Technology Langer Kamp 19b Braunschweig 38106 Germany Technische Universität Braunschweig Institute for Particle Technology Volkmaroder Straße 4 Braunschweig 38104 Germany

Hydrogen is one of the most promising solutions for decarbonising the industrial sector, particularly the chemical and steel industries. To utilise hydrogen as a mobile energy carrier in heavy-duty applications such as transportation, it is necessary to convert the chemically bound energy into electrical energy to power electrical systems. Fuel cell technologies, in particular Proton Exchange Membrane Fuel Cells (PEMFC), are crucial in this regard, as they efficiently convert hydrogen and oxygen into electricity and water. It is expected that production capacity will continue to grow, especially in the heavy-duty sector, and that the need for development will increase significantly. As a result, larger numbers of PEMFCs will reach the end of their life cycle. Successful closed-loop production requires optimising material use, making production processes more efficient, and recovering valuable materials. In order to optimise material, use and recover valuable resources such as platinum and fluorine-containing polymers and extend the product life cycle through reuse, aspects such as disassembly, reuse, remanufacturing and recycling must be considered before mass production. This publication aims to provide an overview of disassembly strategies and technologies for PEMFC stacks used in heavy-duty applications. It analyzes the general structure and layout of PEMFC stacks, with a focus on the Bipolar Plate (BPP), the Membrane Electrode Assembly (MEA) and the gaskets or seals. Various materials and designs of these components result in a wide spectrum of requirements regarding the handling and disassembly technologies. The outcome is a matrix show casing potential disassembly technologies for common PEMFC stack layouts, along with the expected limitations arising from different component and material combinations and their characteristics. The results of these investigations enable a more efficient development of automated disassembly processes for PEMFCs by providing app

关键词： Disassembly technologies Automation Proton-Exchange-Membrane Fuel Cells (PEMFC) Circular economy Resource efficiency

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Characterization of the high-pressure suspension jet for efficient cutting and abrasive circularity

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CIRP Annals 2025年

作者： Morczinek, Florian Dix, Martin Wertheim, Rafael Institute for Machine Tools and Production Processes Technical University of Chemnitz Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz Germany Braude College of Engineering Karmiel Israel

To optimize the workpiece removal process and maximize the fraction of reusable abrasive particles, it is necessary to ascertain the characteristics of the high-pressure suspension jet process, including the kinetic energy of the particles in the jet. In this study, the particle velocity and the change in their size were measured and analyzed. It was found that due to breakage the average particle size decreases by up to 35 % during the acceleration process in the nozzle. The results showed that the particle size has insignificant influence on particle velocity, while the kinetic energy of an average particle decreased by up to 72 %. © 2025 The Authors

关键词： Kinetic energy

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Mould-integrated mechatronic fixture for error compensation in injection overmoulding of optoelectronic devices 20

Mould-integrated mechatronic fixture for error compensation ...

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20th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2020

作者： Rentzsch, Hendrik Perz, Stephan Schwarze, Martin Fraunhofer Institut for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz09126 Germany

ISBN: (纸本)9780995775176

Optoelectronic devices consist of electrical and optical components that are usually manufactured separately and assembled subsequently. To further enhance functional quality and at the same time shorten the production process, a new approach combines both steps by over-moulding the electric components with the lens material using injection moulding. During this process, aligning the electric components (e.g. LEDs) towards the lens geometry is a critical factor allowing for only very small tolerances. The accuracy of positioning the functional components on the printed circuit board (PCB) often does not fulfil the requested demands so that there is a need for compensating misalignment errors. For that purpose, a mould-integrated mechatronic fixture was developed, allowing for measurement-based alignment of optoelectronic components towards lens geometries within the injection-moulding tool. Principle concepts were derived incorporating functional requirements as well as boundary conditions for mould integration, resulting in a 3-DOF mechatronic fixture based on a compliant mechanism with piezo actuators. Model-based dimensioning and design of the prioritized principle as well as capabilities of the developed system will be discussed within the paper. Copyright © Proceedings of the 20th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2020. All rights reserved.

关键词： Injection molding

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