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Component reuse strategy (CRS) for continuous reinforced thermo-sets enabling circular economy

Journal of Remanufacturing 2022年第3期12卷 339-355页

作者： von Freeden, Justus Husemann, Alexander Caba, Stefan Fraunhofer Institute or Machine Tools and Forming Technology Chemnitz Germany EDAG Engineering GmbH Fulda Germany

A circular economy, effective technologies for the recycling and reuse of fiber-reinforced plastics (FRPs) are essential to keep these materials attractive for use in various products against the backdrop of stricter environmental regulations. This paper provides an overview of the current state of the art in the recycling and reuse of end-of-life (EOL) fiber reinforced plastic (FRP) products. A significant proportion of EOL FRP products are thermally recycled or used as fillers in the cement industry. Complementary to the existing approaches of structural reuse of FRP is presented in this paper as component reuse strategies (CRS). Both approaches avoid separation or destruction (downgrading) of the composite materials. An application example for the reuse of a carbon-fiber reinforced plastics (CFRP) base frame of an electric vehicle platform is given and analyzed with respect to known design for reuse approaches. The proposed CRS has great potential to complement existing approaches and slow down resource consumption. In addition, extended service life can make CFRP materials more economically attractive. However, further developments are needed as well as the transfer of the principle to other applications. © 2022, The Author(s).

关键词： Automotive Carbon fiber Circular economy Design for reuse Fiber reinforced plastics

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Integration of Digitization and Sustainability Objectives in a Maturity Model-Based Strategy Development Process 18th

Integration of Digitization and Sustainability Objectives in...

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18th Global Conference on Sustainable Manufacturing, GCSM 2022

作者： Münnich, Marc Stange, Maximilian Süße, Marian Ihlenfeldt, Steffen Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany Institute of Mechatronic Engineering Technische Universität Dresden Dresden Germany

ISBN: (纸本)9783031288388

Political, technological and economic changes force manufacturing companies to shift their strategic alignment towards green and digitized technologies. The parallel advances in those technologies raise questions regarding economic, environmental and social sustainability issues that are challenging to integrate into corporate strategy. Recently, sustainable energy supply has gained additional attention as a critical resource for production. Digital transformation is a diverse intracompany process and requires adequate strategies. Maturity models are a well-known and established approach to define strategic improvement measures. Various versions of separate maturity models to either examine the current state of digitization or sustainability have been developed and there are few models to support both dimensions adequately. Therefore, the authors propose a strategy development process, which utilizes a combined maturity model for both domains in one framework. A review on sustainability-related maturity models as well as the connection to digitization aspects is conducted. Based on this, an existing model is extended. The model is tested in a case study to compare the impact of the models’ adaptions. © 2023, The Author(s).

关键词： Sustainable development

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Simulation of geometrical errors during application of a confocal sensor system for the measurement of large components with high aspect ratios 15

Simulation of geometrical errors during application of a con...

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15th International Conference and Exhibition on Laser Metrology, Coordinate Measuring machine and machine Tool Performance, LAMDAMAP 2023

作者： Teicher, Uwe Gollee, Christian Seidel, André Ihlenfeldt, Steffen Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden Germany Institute of Mechatronic Engineering Technische Universität Dresden Dresden Germany

ISBN: (纸本)9781998999125

Machining of large components for the aerospace industry requires, in addition to sophisticated machining strategies a targeted monitoring of the machining quality due to the enormous demands on precision. For the acquisition of the as-is geometry after single machining steps, a non-contact system based on a confocal chromatic sensor was developed, with whose help the as-is geometry can be compared with the target geometry even in deep cavities at aspect ratios up to 40. The sensor system is coupled with the standard interfaces to a machine tool and performs measuring cycles based on modified NC programs. Data acquisition is done with a control-connected EDGE system. The result of the target/as-is comparison is the basis for CAM planning for subsequent machining. In addition to the design of the measuring system and the integration into the ecosystem of the machine system, a concept to calibrate the measuring system for operation on the machine tool was developed. Based on a simulation model of the measurement system various aspects of the calibration approach were analysed. © euspen Headquarters March 2023.

关键词： Geometry

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Adhesion Reduction in Plastics Processing by means of laser-generated Microstructuring

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Procedia CIRP 2024年 125卷 130-135页

作者： Eric Gärtner Justus von Freeden Michael Schreiter Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Strasse 88 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Hermann-Münch-Strasse 2 38440 Wolfsburg Germany

Almost all production processes for manufacturing plastic or fiber reinforced plastic (FRP) components have in common that plastic and a steel surface are pressed together in the process. To avoid adhesion, the steel belts are coated with polytetrafluoroethylene (PTFE), ceramics or perfluoroalkoxy (PFA) during calendering, for example. However, the high temperatures of over 250 °C and the alternating mechanical load lead to damage of the coating. This results in adhesion of the coating to the product and loosening of the coating. Due to this, the surface quality of the organic sheets is reduced, and the production process is negatively affected. As the surface function can be controlled by material and surface patterns with different length scales (nm - µm), the surface topography of the belt steel was specifically modified in the roughness and microstructure level in order to reduce the adhesive interaction with the organic sheet. These microstructures were tested in extensive experiments and the results will be presented in this publication. True to the motto from nature to innovation, the micro- and nanostructured surface of the lotus leaf, which is provided with a fine substructure, was used as reference. The aim was to generate such a hierarchical structure by means of direct laser writing in order to avoid adhesions on production surfaces and to substitute the coating of steel strip surfaces. Additionally, a testing method close to the process was developed and evaluated to test the laser structured microstructures, which will also be presented.

关键词： adhesion reduction laser microstruturing surface functionalisation calendering

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Memory Adaptive and Spatially Specialized Model Ensembles for Industrial Anomaly Detection 27

Memory Adaptive and Spatially Specialized Model Ensembles fo...

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27th European Conference on Artificial Intelligence, ECAI 2024

作者： Wagenstetter, Marco Landerer, Niklas Thyroff, Johannes Aicher, Thomas Hellmich, Arvid Ihlenfeldt, Steffen Powertrain Production System Planning BMW Group Germany School of Computation Information and Technology Technical University of Munich Germany Institute for Machine Tools and Forming Technology Fraunhofer IWU Germany

ISBN: (纸本)9781643685489

Industrial anomaly detection models proved to be a viable solution for automating the task of visual inspection. Despite their effectiveness, the deployment of current deep learning models for anomaly detection for high-resolution images involves large memory requirements, which are unattainable in industrial deployments on edge devices. In this paper we introduce a tiling approach for a memory bank based feature embedding model to reduce the memory requirements during training and inference. Additionally, we analyze the correlations between image size, dataset size and required memory. To evaluate the detection performance of different tiling schemes, we create and apply a real industrial training and validation dataset collected in the electric motor housing production of the BMW Group. Our experiments show that depending on the tiling scheme the overall required memory can be decreased by a factor of 12 while leaving the detection performance unchanged and even increase the detection performance when the memory requirement is only halved. This venture underscores the viability of our tiling approach in real-world industrial applications but also marks a significant leap towards resolving the issue of resolution limitations in deploying advanced anomaly detection models. © 2024 The Authors.

关键词： Anomaly detection

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Tool-holder integrated printed piezoceramic sensors for process state classification and tool-wear progress evaluation in turning 20

Tool-holder integrated printed piezoceramic sensors for proc...

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20th CIRP Conference on Modeling of Machining Operations in Mons, CIRP CMMO 2025

作者： Panesso, Miguel Berthold, Jan Hamm, Lucas Li, Zongshuo Drossel, Welf-Guntram Bergs, Thomas Fraunhofer Institute for Machine Tools and Forming Technology Nöthnitzer Str. 44 Dresden01187 Germany RWTH Aachen University Campus-Boulevard 30 Aachen52074 Germany

Tool condition monitoring strategies in turning processes, using multiple sensor sources to measure dynamic quantities (e.g., force, acoustic emissions, acceleration), has gained significant attention in conjunction with machine learning methods. As a novel approach, the introduction of printed piezoceramic thick films in machine tools allows the customization of sensor shape and placement, optimized to fit the tool holder's geometry and process boundary conditions. This work proposes integration concepts using two configurations of printed piezoceramic sensors. This includes the use of a finite element simulation to estimate the generated electric charge from sensors on three locations on the tool holder, induced by transient mechanical loading. The design is validated under controlled mechanical loading and tested across various cutting conditions and tool-wear states. Signal information content from each sensor location, relative to different machining conditions, is assessed through recursive feature elimination and validated using dimensionality reduction. Finally, tool-wear progress is evaluated using the selected features. © 2025 The Author(s).

关键词： Thick films

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Topology optimization of nonlinear elastomer engine mounts considering the transfer behavior

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Forschung im Ingenieurwesen 2025年第1期89卷 1-10页

作者： Bahr, S. Jacobs, G. Höpfner, G. Hensel, E. Troge, J. Rapp, T. Institute for Machine Elements and Systems Engineering RWTH Aachen Aachen Germany Institute for Machine Tools and Forming Technology Fraunhofer Dresden Germany

Increasing global competition among electric vehicle manufacturers has elevated the Noise, Vibration, and Harshness (NVH) properties of drivetrains to a key quality feature. Unfavorable NVH properties occur when the drivetrain’s dynamic excitation forces excite modes of the sound-transmitting components at the respective eigenfrequencies. An established strategy to avoid this unwanted NVH behavior is topology optimization (TO), as it can shift unwanted modes of the drivetrain out of the excitation frequency range through geometrical adaptations using finite-element (FE) simulation. Another way to significantly influence unwanted NVH behavior in electric vehicle drivetrains are elastomer engine mounts which are employed to isolate the engine’s vibrations from the surrounding system and to dissipate vibrational energy. However, the effectiveness of these functionalities is limited in frequency ranges of local elastomer modes. Despite TO being well-established, challenges are given in shifting elastomer modes due to the complex material behavior. Firstly, the material’s softness results in an uncontrollably high density of local mount modes for TO, which presents a challenge in developing engine mounts without modes in the drivetrain’s excitation range, especially for electrified engines. Secondly, the elastomer’s nonlinear material impedes calculating the component’s modes with a linearized material approach. The goal of this contribution therefore is to develop a method that considers the complex material behavior of engine mounts in a TO process. To achieve this goal, the ideal transfer behavior of the engine mount, and consequently the positioning of mount modes within the frequency range, is determined based on the sound-transmitting structure and used as an objective for the optimization process. To consider the elastomer’s nonlinear transfer behavior during optimization, material parameters for each considered frequency are applied. The

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Influence of the cutting edge preparation of carbide punching tools for punching of ultra-high strength steel strips 7

Influence of the cutting edge preparation of carbide punchin...

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7th CIRP Conference on Surface Integrity, CSI 2024

作者： Redžić, Nermin Winter, Sven Galiev, Elmar Baron, Sarah Stein, Christian Höfer, Markus Regel, Joachim Kräusel, Verena Dix, Martin Chemnitz University of Technology Institute for Machine Tools and Production Processes IWP Reichenhainer Str. 70 Chemnitz09126 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 Chemnitz09126 Germany Fraunhofer Institute for Surface Engineering and Thin Films IST Riedenkamp 2 Braunschweig38108 Germany

In order to ensure a robust punching process of ultra-high strength steel spring strips using carbide punching tools, a high stability of the cutting edge is required. Here the cutting edge preparation process has a significant influence. In the presented study, high-pressure abrasive water jet technology for cutting edge preparation was designed, investigated and analysed. For defining the optimal cutting edge shape regarding stresses, a numerical analysis using LS-DYNA was conducted. Within this analysis, the influence of the cutting edge rounding and symmetry was numerically tested and evaluated. Based on the results, two cutting edge shapes were selected and prepared using the high-pressure abrasive water injection jet technology. The tools were applied in the punching process up to 50, 000 strokes in order to analyse the cutting performance and tool wear. With regard to a highly wear resistant tool for punching, a combination of the abrasive water injection jet preparation routine and a CVD diamond coating are under further investigation and first insights are presented additionally. © 2024 The Authors. Published by Elsevier B.V.

关键词： High strength steel

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Split CFD-simulation approach for effective quantification of mixed convective heat transfer coefficients on complex machine tool models

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Procedia CIRP 2023年 118卷 199-204页

作者： Tharun Suresh Kumar Alexander Geist Christian Naumann Janine Glänzel Steffen Ihlenfeldt Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz Germany

Estimation of mixed heat transfer coefficients on complex CFD-simulation models of 5-axis machine tools/ machining centers poses a whole new set of challenges. The enclosure around the machine which protects the user from chips and machining-process is also responsible for creation of an additional environment which has coolant supply, chips and moving air due to temperature changes and oil-emulsion exhaust. This results in a highly complex CFD model which has inner and outer environments along with multiphase fluid domains. The computational effort required is extremely large. The split-simulation approach divides the simulation model into internal and external environments. The natural convection is emphasized for external environment model and forced convection for internal multiphase environment model. This division significantly reduces the computational efforts involved by neglecting uninfluential solid bodies, cavities etc. and thereby the model size. The external and internal influences are mapped separately onto natural and forced convection coefficients using neural networks, which can be used to predict the combined heat transfer coefficients for any load cases within the training boundaries. The temperature fields obtained from split-simulation model are validated with thermography and temperature sensor readings taken from the machine in the form of a use-case study.

关键词： heat transfer coeffcients CFD simulation Decoupling Genetic Algorithms

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Operational modal analysis used to identify dynamic behaviour of machine tools during milling 16

Operational modal analysis used to identify dynamic behaviou...

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16th CIRP Conference on Intelligent Computation in Manufacturing Engineering, CIRP ICME 2022

作者： Berthold, Jan Regel, Joachim Dix, Martin Drossel, Welf-Guntram Institute for Machine Tools and Production Processes Chemnitz University of Technology Reichenhainer Str. 70 Chemnitz09126 Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 Chemnitz09126 Germany

The dynamic behaviour of machine tools during cutting is investigated by Operational Modal Analysis (OMA), which overcomes the disadvantages of the Experimental Modal Analysis (EMA) using excitation methods such as shakers or hammers, not considering effects occurring during operation. The assumptions of OMA such as time-invariance and white noise excitation are difficult to fulfil considering the boundary conditions of a milling process. The results show that feed motions classify the varying dynamic behaviour in the working space and excitation is controlled by modification of the milling conditions. Modal Parameters, identified by OMA, provide process-related results enabling to improve performance. © 2023 Elsevier B.V.. All rights reserved.

关键词： machine tools

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