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

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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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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Streamlining the development of smart product-service systems

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Procedia CIRP 2025年 134卷 699-704页

作者： Anton Mauersberger Heiner Reinhardt Mahtab Mahdaviasl Steffen Ihlenfeldt Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

The ongoing digitalization of manufacturing leads to the development of smart product-service systems (smart PSSs), where smart, connected products (SCPs) and complementary smart services along with human interaction shape an environment for cooperative business value generation. However, due to the complex nature of smart PSSs, simplified approaches for their strategic development are required. Here, we propose a methodology for the conceptualization and continuous development of smart PSSs. In doing so, we discuss cumulative stages for smart PSSs based on various technological capabilities. Additionally, the time for business value generation in each stage and the need for human interaction are taken into consideration. The introduced methodology is applied to the use case of a multi-sensory tool holder for milling machines.

关键词： Smart PSS Smart service Smart technologies Product-service system Innovation management Sustainable development Lifecycle Decision making Methodology Digital manufacturing system

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Aluminium-Matrix-Composites (AMC) for Hot Forged Components 14th

Aluminium-Matrix-Composites (AMC) for Hot Forged Components

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14th International Conference on technology of Plasticity, ICTP 2023

作者： Graf, Marcel Pippig, Robert Lehnert, Tim Jedynak, Angelika Härtel, Sebastian CMMC GmbH Saxony Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technologies IWU Saxony Chemnitz Germany Brandenburg University of Technology Cottbus-Senftenberg Cottbus Germany

ISBN: (纸本)9783031410222

The development of new materials or material systems is always accompanied by the development of processing technologies suitable for the material. The reduction of process steps, the saving of material and the optimization of material properties are aims of forming processes. The basis for this is the comprehensive characterisation of the thermos-physical and thermos-mechanical technologically relevant material behaviour, taking into account the real process conditions. In the present work, the material-specific process limits were determined by means of experimental simulation and used in the numerical simulation in order, on the one hand, to identify the forming steps for optimizing the manufacturing conditions and, on the other hand, to be able to set the final material properties. It was essential to homogenize the casting microstructure for the forming processes and to adjust it to globulitical grains by solution annealing. The previously limited forming behaviour of the cast AlSi9Mg alloy with 20 vol.-% SiC could be increased thus to forging-relevant plastic strains without occurring damages. Based on the comprehensive temperature-dependent material data, a one-step and resource-efficient manufacturing process for AMC materials by hot forming could be developed with the help of the FE software Simufact forming and validated in reality under near-industrial conditions. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Corrosion resistance

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An analysis of biomechanical requirements and actuating technologies of biomimetic hand exoskeletons regarding to driving force and stroke

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Procedia CIRP 2024年 125卷 24-29页

作者： Alina Carabello Kenny Pagel Welf-Guntram Drossel Professorship Adaptronics and Lightweight Design University of Technology Chemnitz Fraunhofer Institute for Machine Tools and Forming Technology IWU

Exoskeletons have gained importance recently. In the case of musculoskeletal diseases, they can restore or support the mobility of injured body parts; in everyday life, they can relieve the musculoskeletal system and thus contributes to the preservation of health into old age. However, active systems face challenges due to the efficient and reliable actuators. In the following, the example of the hand will be used to investigate what influence the individuality of the hand under consideration has on the selection of a suitable actuator about force and stroke. The literature outlines that tendon-driven mechanism with a biomimetic design are a promising approach for hand exoskeletons: The finger is actively moved by an actuator using artificial tendons positioned along the finger to match anatomical structures. For this purpose, actuators based on electromagnetic or pneumatic principles, and smart materials are described. The requirements for force and stroke of the drive can be derived from the analysis of finger kinematics. In this study the finger kinematics of 13 subjects were analyzed. The results show a scatter in stroke and force depending on the finger considered. To select a suitable actuator for the biomimetic hand exoskeleton, these results are compared with the force and stroke characteristics of various actuating principles. The comparison reveals that the choice of the actuator depends on the intended primary support for the hand (movement, endurance, grip strength). Hence, it can be deduced that step drivers meet the force and stroke requirements and may be a suitable alternative.

关键词： exoskeleton tendon-driven step driver actuator hand injury finger movement

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Simulation-Based Improvement of Production in the Tex-Tile Industry—A Case Study 9th

Simulation-Based Improvement of Production in the Tex-Tile I...

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Production Processes and Product Evolution in the Age of Disruption - Proceedings of the 9th Changeable, Agile, Reconfigurable and Virtual Production Conference CARV2023 and the 11th World Mass Customization and Personalization Conference MCPC2023

作者： Grobis, Maxi Münnich, Marc Reinhardt, Heiner 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)9783031348204

Due to the high volatility of market demand and an increasing individualization, traditional textile manufacturing companies are required to carry out efficient production planning and scheduling (PPS). Highly complex manufacturing operations and a heterogeneous landscape of production equipment in terms of age, technology and automation level as well as a low level of digitalization hamper transparency in PPS, even though the demands on delivery reliability, lead times and flexibility are continuously increasing. Therefore, decision-making is typically based on fragmented production data and practical knowledge of individual workers in daily production that makes overall production opaque. To overcome this, the authors conducted a detailed process analysis of a medium-sized textile manufacturer and carried out a simulation study to improve daily production routines on the shop floor. This included the analysis of the heterogeneous production data, the management of missing data and the decision to implement a discrete-event simulation model. The simulation study focused on testing isolated production strategies, identifying potential improvements in terms of organizational processes, detecting data leaks as well as designing a model for discrete-event simulation (DES). As a result, a roadmap to establish a seamlessly integrated hardware and software infrastructure was derived. This consists of a catalogue of best practices for lean production as well as an increased level of digitalization on the shop floor and considers the current state of digitalization of the company. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Textile industry

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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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Investigation of Surface Characteristics in Magnetic Field assisted Electrical Discharge Machining 7

Investigation of Surface Characteristics in Magnetic Field a...

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7th CIRP Conference on Surface Integrity, CSI 2024

作者： Bui, Viet D. Martin, André Berger, Thomas Schubert, Andreas Chemnitz University of Technology Professorship Micromanufacturing Technology Reichenhainer Str. 70 Chemnitz09126 Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 Chemnitz09126 Germany

Electrical discharge machining (EDM) has demonstrated its promising potential for surface modification. The integration of materials from tool electrode or powder that is mixed into the dielectric fluid has proven to modify the workpiece surface to enhance its mechanical properties, realize antibacterial effects, or increase biocompatibility. Recent EDM studies showed that due to non-contact forces, properties of the modified surface such as roughness values and the thickness of modified layer were significantly influenced when using magnetic field assisted EDM. Consequently, in this study, an external magnetic field with a strength of 0.66 T is used to assist the material transfer from tool electrode to workpiece surfaces during the EDM process. Pure silver and copper tools with a diameter of 2 mm are used to modify surfaces of Ti6Al4V workpieces at a discharge energy of 125 µJ with different polarities. Results show that the assistance by magnetic field significantly increases the content of transferred material from tool electrode to the workpiece surface. Additionally, it increases material removal rate and reduces the modified layer thickness. Magnetic field assisted EDM is a potential technology for improving the efficacy of the EDM surface modification. © 2024 The Authors. Published by Elsevier B.V.

关键词： Titanium alloys

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