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Temperature optimization of PEM water electrolyzers for minimum hydrogen prices

International Journal of Hydrogen Energy 2025年 138卷 58-63页

作者： Zwaschka, Gregor Thiel, Laura Leskau, Roman Fraunhofer Institute for Machine Tools and Forming Technology Theodor-Körner-Allee 6 Zittau02763 Germany Faculty of Administration Technical University Bergakademie Freiberg Business Akademiestraße 6 Freiberg09599 Germany Faculty of Business Administration and Industrial Engineering Zittau/Görlitz University of Applied Sciences Schliebenstraße 21 Zittau02763 Germany Faculty of Natural and Environmental Sciences Zittau/Görlitz University of Applied Sciences Külzufer 2 Zittau02763 Germany

Increasing the temperature of PEM electrolyzers improves their efficiency but reduces their lifetime. This suggests the existence of an ideal temperature - characterized by a minimum hydrogen price - at which the electrolyzer is sufficiently efficient and long lived. Here, we evaluate the ideal temperature of a PEM electrolyzer as a function of material (membrane thickness, exchange current density), operational (current density, voltage degradation) and economic parameters (CAPEX, OPEX and electricity price). Increases in efficiency with temperature are calculated from a cell model. The lifetime decrease is taken from literature data and is supported by a model of PEM degradation. The ideal operating temperature decreases from 80 °C at 0.15 €/kWh (and higher) to 40 °C at 0.01 €/kWh. The relative influence of material, operational and economic parameters on the levelized cost of hydrogen is quantified, allowing for clear recommendations on a path to cost competitive hydrogen. © 2025 The Authors

关键词： Electrolysis

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Influence of engagement parameters on estimation of tangential cutting force using high-frequency process data of the machine tool

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Procedia CIRP 2023年 118卷 537-542页

作者： Michal Rytir Jonas Rönnecke Albrecht Hänel Petr Kolar Steffen Ihlenfeldt Czech Technical University in Prague Czech Institute of Informatics Robotics and Cybernetics Department of Industrial Production and Automation Jugoslávských partyzánů 1580/3 160 00 Prague Czech Republic Fraunhofer Institute for Machine Tools and Forming Technology IWU Department of Production Digital Twin Nöthnitzer Straße 44 Dresden Germany Technische Universität Dresden Institute of Mechatronic Engineering Chair of Machine Tools Development and Adaptive Controls 01062 Dresden Germany

The machining of high-value products needs advanced quality control to avoid the risk of expensive follow-up operations performed on parts with unacceptable quality. This situation requires the in-process or close to in-process control of the machining operation. The tangential cutting force is a parameter that characterizes the force interaction between the specific workpiece material and the specific tool geometry. This paper presents a method for a tangential cutting force calculation along the given tool path based on processing of the high-frequency data acquired from the machine tool control system with support of the geometric material removal model. The calculated data are compared with the reference dynamometer results. The influence of the variable engagement parameters is demonstrated and discussed from the perspective of the in-process workpiece quality control.

关键词： In-process monitoring leakage model cutting force model spindle current edge computing

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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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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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Reaming of carbon fibre reinforced plastics: Influence of tool geometry on process forces and tool wear 14

Reaming of carbon fibre reinforced plastics: Influence of to...

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14th CIRP Conference on Intelligent Computation in Manufacturing Engineering, CIRP ICME 2020

作者： Sauer, Konstantin Putz, Matthias Chemnitz University of Technology Reichenhainer Strasse 70 Chemnitz09126 Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Strasse 88 Chemnitz09126 Germany

Due to the high abrasive wear and the tendency to workpiece damages, the manufacturing of high-quality bores in carbon fibre reinforced plastics (CFRP) is still one of the major goals in tool development. In this work, reaming tests are performed on CFRP in order to characterise the relationship between tool geometry, process forces and tool wear. After a preliminary investigation of a taper reamer, diverse carbide tools have been tested which exhibit different values of rake and clearance angle. The forces measurement took place using a rotating dynamometer, while the evaluation of the tool wear has been realised by microscopic images via structured light projection. Different forms of wear appear, while hardly any differences in the force curves can be detected when applying different angles of the cutting wedge. © 2021 The Authors. Published by Elsevier B.V.

关键词： Carbon fiber reinforced plastics

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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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Characterization of vibration in continuous generating grinding and resulting influence on tooth flank topography and gear excitation

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Procedia CIRP 2021年 99卷 208-213页

作者： Jonas Böttger Simon Kimme Welf-Guntram Drossel Institute for Machine Tools and Production Processes IWP Chemnitz University of Technology Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

Besides harmonic meshing frequencies, excitation behavior of gears is highly affected by micro geometry of tooth surface caused by waviness on gear flank topography. Errors in finishing processes like continuous generating gear grinding are examined to demonstrate their impact on gear flank topography under consideration of characteristic waviness with a simulation model. Results of an experimental investigation on manufactured topography and measured transmission error show well correlation with the model. The pursued analysis of characteristic cutting volume in frequency domain of systematically considered process errors is a reasonable step towards the prediction of process conditions in the manufacturing process.

关键词： Grinding Gear Vibration Simulation

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Data Acquisition Framework for spatio-temporal analysis of path-based welding applications

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Procedia CIRP 2024年 130卷 1644-1652页

作者： Georgij Safronov Heiko Theisinger Vasco Sahlbach Christoph Braun Andreas Molzer Anabelle Thies Christian Schuba Majid Shirazi Thomas Reindl Albrecht Hänel Philipp Engelhardt Steffen Ihlenfeldt Peter Mayr BMW AG Petuelring 130 80788 München Germany Technical University of Munich Chair of Materials Engineering of Additive Manufacturing Freisinger Landstraße 52 85748 Garching bei München Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 01187 Dresden Germany nebumind GmbH Willy-Messerschmitt-Straße 1 82024 Taufkirchen Germany

The use of digital technologies in industrial manufacturing reduces operational costs and improves production quality. The “Framework for Spatiotemporal Production Data Acquisition” (PathSense) aims to improve access and usability of production data by applying a common data ecosystem. Through integrating operational technology (OT) and information technology (IT), PathSense supports decision-making and process optimization. The framework uses the concept of digital shadows to collect critical information from sensors within the continuous manufacturing processes, e.g., welding or gluing lines. Spatial and temporal digital shadows are developed in accordance with human spatial cognition to support sophisticated–yet intuitive–human-computer interactions without the need for advanced data science skills. The backbone of the framework consists of robust data pipelines with a setup incorporating modern IT protocols, such as OPC UA and MQTT, to support the efficient acquisition and management of data. The paper addresses the challenges associated with the combination of IT and OT in cyber-physical systems, stressing modern complex data-intensive manufacturing as one exemplary domain to be tackled by scalable and secure data architectures. The paper identifies two major future directions: refining data integration processes and embedding advanced machine learning algorithms to enable automated data analysis and improve process quality monitoring. In summary, PathSense proposes a data-driven approach for quality inspection in manufacturing, which may eventually enhance industry practices and move towards data-driven decisions and increased operational flexibility.

关键词： PathSense digital twin welding process data acquisition spatiotemporal analysis defect detection OPC UA MQTT AI

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Everting of tubular net structures based on Shape Memory Alloys

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Engineering Research Express 2021年第2期3卷

作者： Hensel, Sebastian Boxberger, Lukas Weisheit, Linda Schellnock, Julia Thielsch, Juliane Riedel, Frank Drossel, Welf-Guntram Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden01187 Germany Professorship for Adaptronics and Lightweight Design Chemnitz University of Technology Chemnitz09126 Germany

Foldable technical structures can be used to provide a temporary additional volume. In nature, a tubular folding application is the extension of the snail eye. The present study uses this approach. A transformation into a technical application is only successful if the high eversion loads are considered. The study aims to develop a method to realize such structures based on a metallic wire net structure. The tube consists of Shape Memory Alloy (SMA) pieces connected by developed crimp elements produced by additive manufacturing. Additive manufacturing was used to provide a fast and effective way to make several crimp element geometries available to define a preferred variant. In a preliminary building study, the printing parameters for crimp element production were improved. The tubular structure development is assisted by numerical simulation of the eversion process. The SMA material model parameters were identified with experimental tension tests. A feasible way to connect additively manufactured crimp elements with SMA wire was found within a joining method study. Tension tests of the connections protect against pull-out failure. The eversion process was investigated using a high-speed camera system. Multiple eversion of the developed structure is possible without failure. © 2021 The Author(s). Published by IOP Publishing Ltd.

关键词： 3D printers

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

SSRN

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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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