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

作者： Uhlmann, E. Polte, J. Koprowski, S. Kochan, J. Borsoi Klein, T. Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 Berlin10587 Germany Institute for Machine Tools and Factory Management IWF Technische Universität Berlin Pascalstr. 8-9 Berlin10587 Germany

ISBN: (纸本)9780995775176

The constant development and improvement of mechanical and chemical properties of high performance ceramics allows the expansion of its actual applications. In comparison to metal materials, the use of novel high performance components can offer numerous advantages. In turbomachinery, a full ceramic impeller can fulfil the requirements of efficiency and high turbine inlet temperatures combined with lower cooling requirements, reduced combustion emissions and fuel consumption. This is feasible not only thanks to the properties of the ceramics, but also by the interaction of this with simulation, design optimization, manufacturing processes and a high quality finishing by hard machining. However, the machining of brittle material components with complex geometries remains a challenge in terms of resultant surface characteristics, tribological properties, geometric accuracy and process costs. In this scenario, 5-axis grinding with mounted points and innovative strategies provide new possibilities for the manufacturing of these complexes components. The current work aims at a practice-oriented design and the following hard machining of a hot isostatically pressed silicon nitride (HIPSN) impeller with complex geometry and high requirements, gathering low geometrical deviations, reduced brittle fractures and roughness at the ground part. To achieve these objectives, different machining strategies and parameters are tested and correlated with the resulting quality of the component. Simulation techniques are also shown to ensure optimum operating conditions for the ceramic component. Copyright © Proceedings of the 20th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2020. All rights reserved.

关键词： Silicon nitride

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Determination of critical local straining conditions for solidification cracking at laser beam welding by experimental and numerical methods

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PAMM 2024年第2期24卷

作者： Nasim Bakir Andrey Gumenyuk Michael Rethmeier Bundesanstalt für Materialforschung und prüfung (BAM) Berlin Germany Technische Universität Berlin Berlin Germany Fraunhofer Institute for Production Systems and Design Technology IPK Berlin Germany

The phenomenon of solidification cracking has been the subject of numerous research projects over the years. Great efforts have been made to understand the fundamentals of hot cracking. It is generally agreed that solidification cracks form in the solidification range between the liquidus and solidus temperatures under the combination of thermal, metallurgical and mechanical factors. There is still a need to determine the time-resolved strain distribution in the crack-sensitive region in order to analyse the local critical conditions for solidification cracking phenomena. This was a strong motivation for the development of a measurement system used in this study to estimate the local strains and strain rates in the zone where the solidification crack is expected to occur. The laser beam welding experiments were conducted using the Controlled-Tensile-Weldability test (CTW test) to apply an external strain condition during welding to generate solidification cracks. The CTW test is a test method for investigating the susceptibility of laser-welded joints to solidification cracking, in which the sample can be subjected to a defined strain at a defined strain rate during welding. In combination with experimental investigations, numerical simulations provide spatially detailed and time-dependent information about the strain development during the welding process, especially regarding the critical conditions for solidification cracking. Therefore, this tool was also used in the present study to evaluate the accuracy of measurement methods and to estimate experimentally derived values and their concrete influence on the formation of solidification cracks. By integrating experimental methods and numerical simulations, this study investigates the spatially resolved and temporally changing development of strain during welding, with a particular focus on the critical conditions that lead to the formation of solidification cracks. The use of numerical simulations serves a dual p

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Low-Cost Embedded Vision for Industrial Robots: A Modular End-of-Arm Concept

Low-Cost Embedded Vision for Industrial Robots: A Modular En...

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International Conference on Emerging Technologies and Factory Automation (ETFA)

作者： Ole Kroeger Felix Wollschläger Jörg Krüger Fraunhofer Institute for Production Systems and Design Technology IPK Berlin Germany University of Stuttgart Stuttgart Germany

ISBN: (数字)9781728189567

ISBN: (纸本)9781728189574

In this work we present our first prototype of a modular, low-cost end-of-arm concept for industrial robot applications. The goal is a faster, more flexible and cost-effective alternative compared to current industrial solutions. We use an embedded single-board computer and three cameras as a sensor base for the new system. The scope of robot application is supposed to as wide as possible (e.g. object detection, bin picking, assembly tasks and quality control tasks). We discuss some industry and low-cost-hardware solutions, introduce our system and deliver a proof of concept. Furthermore we use the system to accomplish a vision based pick and place task.

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Concept for a modular system model for energy-efficiency monitoring of factory supply systems

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AIP Conference Proceedings 2024年第1期2989卷

作者： Stefan Sigg Gregor Thiele Marvin Trapp Jörg Krüger Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 10587 Berlin Germany Institute for Machine Tools and Factory Management Technische Universität Berlin Pascalstr. 8-9 10587 Berlin Germany

Companies in the manufacturing industry are facing the challenges of both reducing energy costs as well as driving decarbonization. As a result, energy efficiency optimization of factory operations is gaining importance. Due to their high share in the energy consumption of a factory, industrial supply technology is of interest for these optimizations. Particularly cooling systems used in factories often offer considerable potential for energy efficiency improvements, some of which can be realized through optimized control strategies. Optimization based on control technology in particular requires a high level of energy consumption transparency in order to identify potentials and measure efficiency improvements. However, industrial supply systems are often complex and interconnected facilities composed of a combination of various individual assets. Consequently, the energy efficiency monitoring and analysis of such systems typically require a high manual effort. To reduce this effort, we propose the development of a modular system model which decomposes complex, interconnected energy systems to individual, recurring assets. The system model consists of a standardized data exchange format, a standardization of structural and behavioral models in the form of a model library for industrial supply systems at different hierarchy levels, and a standardized interface for using the data model on a target platform such as an energy management software. The data model of the data exchange format maps data points such as the control and media interfaces as well as energy performance indicators of the individual assets in a standardized and consistent way. Similar to the concept of digital twins, the knowledge of manufacturers and operators about the system is to be seamlessly combined and utilized. By connecting the interfaces of the individual asset models, an aggregate structural model of a factory supply system is built. The aggregate structural model enables the calculation

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Fully coupled wet cylindrical turning simulation using the Finite-Pointset-Method

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Procedia CIRP 2021年 102卷 43-48页

作者： Eckart Uhlmann Enrico Barth Alexander Quellhorst Tobias Seifarth Jörg Kuhnert Kaissar Nabbout Martin Sommerfeld Technische Universität Berlin Institute for Machine Tools and Factory Management (IWF) Chair of Machine Tools and Manufacturing Technology Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Industrial Mathematics ITWM Fraunhofer-Platz 1 67663 Kaiserslautern Germany Otto von Guericke University Magdeburg Institute of Process Engineering Universitaetsplatz 2 39106 Magdeburg Germany

In industrial machining operations, many turning processes are carried out under wet conditions. In contrast, most simulation tools are only suitable for dry cutting processes due to challenges of modeling fluid-structure-interactions (FSI). In this paper, a wet, fully coupled cutting simulation using the Finite-Pointset-Method (FPM) is presented and validated for industrially relevant cylindrical turning. To facilitate the required reduction of the calculation effort, different routines like adaptive numerical discretization are applied. The results indicate different cutting fluid effects like evaporation areas around the chip.

关键词： Turning Cutting fluid Simulation

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Generating annotated training data for 6D object pose estimation in operational environments with minimal user interaction

arXiv

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arXiv 2021年

作者： Koch, Paul Schlüter, Marian Thill, Serge Radboud University Nijmegen6525 HR Netherlands Fraunhofer IPK Institute for Production Systems and Design Technology Pascalstr. 8-9 Berlin10587 Germany Donders Institute for Brain Cognition and Behaviour Radboud University Nijmegen6525 HR Netherlands

Recently developed deep neural networks achieved state-of-the-art results in the subject of 6D object pose estimation for robot manipulation. However, those supervised deep learning methods require expensive annotated training data. Current methods for reducing those costs frequently use synthetic data from simulations, but rely on expert knowledge and suffer from the domain gap when shifting to the real world. Here, we present a proof of concept for a novel approach of autonomously generating annotated training data for 6D object pose estimation. This approach is designed for learning new objects in operational environments while requiring little interaction and no expertise on the part of the user. We evaluate our autonomous data generation approach in two grasping experiments, where we archive a similar grasping success rate as related work on a non autonomously generated data set. © 2021, CC BY-NC-SA.

关键词： Deep neural networks

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Inertial Measurement Unit based Human Action Recognition for Soft-Robotic Exoskeleton

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IOP Conference Series: Materials Science and Engineering 2021年第1期1140卷

作者： Jan Kuschan Moritz Burgdorff Hristo Filaretov Jörg Krüger Fraunhofer Institute for Production Systems and Design Technology IPK Germany

Absence from work caused by overloading the musculoskeletal system lowers the life quality of the worker and gains unnecessary costs for both the employer and the health system. Exoskeletons can present a solution. Typically, such systems struggle with stiffness and discomfort and primarily a lack of battery lifetime. Soft-robotic exoskeletons offer a possibility to overcome these problems by increasing the system flexibility, not limiting the supported DoF and being actuator and joint together. Since soft-robotic exoskeletons can be designed only using power when supporting the wearer, it is possible to increase the battery lifetime by only acting on those actions for which the wearer needs support. Dealing with controls for soft-robotic exoskeleton one major difficulty is to find a compromise between saving energy and supporting the wearer. Having an action-depending control can reduce the supported actions to cover only relevant ones and increase the lifetime of the battery. The system conditions are to detect the user actions in real-time and distinguish between actions which require support and those which do not. We contribute an analysis and modification of human action recognition (HAR) benchmark algorithms from activities of the daily living, transferred them onto industrial use cases containing short and mid-term action and reduce the models to be compatible using embedded computers for real-time recognition on soft exoskeletons. We identified the most common challenges for inertial measurement units based HAR and compare the best-performing algorithms using a newly recorded data set overhead car assembly for industrial relevance. As a benchmark data set we focused on the 'Opportunity' data set. By introducing orientation estimation, we were able to increase the F1 scores by up to 0.04. With an overall F1 score without a Null-class of up to 0.883, we were able to lay the foundation to use HAR for action dependent force support.

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Modeling of the wet immersed tumbling process with the Discrete Element Method (DEM)

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Procedia CIRP 2021年 102卷 1-6页

作者： E. Uhlmann J.-P. Fürstenau Y. Kuche S. Yabroudi J. Polte M. Polte Institute for Machine Tools and Factory Management IWF Technische Universität Berlin Pascalstr. 8-9 Berlin 10587 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 Berlin 10587 Germany CADFEM GmbH Pelikanstr. 13 Hannover 30177 Germany

Immersed tumbling is an industrially established process for finishing of components made of metal, ceramic or plastic. In this process, the components are completely surrounded by a wet, abrasive medium, which allows burrs to be removed and surfaces to be polished. In order to gain specific insights into the influence and flow properties of the abrasive media used in this process, numerical approaches using the Discrete Element Method (DEM) with the Rocky DEM software are presented within these investigations. A complete process simulation could be realised by means of a digital machine tool. The immersed tumbling process with cone-shaped polymer abrasive media is implemented by use of a liquid bridge model. The results were validated by experiments with an industrially used immersed tumbling machine tool and for the first time allow sound statements about the contact conditions and interactions of the abrasive media with the workpiece.

关键词： discrete element method DEM immersed tumbling liquid bridge facetted particles

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Production environment of tomorrow (ProMo): Partially automated repair process of small tool moulds, forming tools, injection moulding tools and sand casting tools

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IOP Conference Series: Materials Science and Engineering 2021年第1期1140卷

作者： Jan Kuschan Vinzenz Müller Stephan Monchinger Oliver Heimann Carsten Niebuhr Oday Kabha Fraunhofer Institute for Production Systems and Design Technology IPK Germany

Small defects in the grain or major damage to a moulded part or tool can bring production to a standstill. SMEs in particular have neither the personnel nor the equipment to repair such damage on their own, so they send it to specialised contractors. The repair process is carried out manually, depending on the accuracy requirements, and is usually completed by a finishing process. This work requires qualified personnel and, at the same time, requires a lot of time in case of larger damages. In this paper we present a way to map the Maintenance, Repair and Operations (MRO) process chain in a partially automated manner. The symbiosis of individual technologies results in a significantly increased efficiency of the MRO process chain, which continues to focus on people and their process knowledge. While Directed Energy Deposition (DED) for the MRO of moulded parts is used widely, usually a high manual effort in measuring the component geometries and teaching of the machine tool paths is necessary. However, there are clear advantages compared to the manufacture of new parts or manual laser welding repair. At the same time, the resource and energy requirements can often be significantly reduced compared to new part production. Promo focuses on automating the time-consuming machine programming by reducing the number of necessary work steps in CAD/CAM-based program creation. Based on a subsequent robot-guided scan, a digital actual 3D model is generated. Due to intelligent path planning algorithms, no manual programming of the robot is necessary and at the same time it is possible to detect components of different sizes, shapes and covers in this system with a minimum of effort. In addition, the operator passes on elementary information, such as the approach path of the milling head, to the subsequent processes by means of finger gestures and can thus significantly reduce tedious CAM programming steps. Now, the scanned component is transferred to a 3D-CAD model and a target

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Process behaviour of micro-textured CVD diamond thick film cutting tools during turning of Ti-6Al-4V

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Procedia CIRP 2020年 87卷 25-30页

作者： Eckart Uhlmann Danny Schröter Institute for Machine Tools and Factory Management (IWF) Technische Universität Berlin 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) 10587 Berlin Germany

Currently, an efficient machining of high-performance materials, such as titanium alloy Ti-6Al-4V, represents a challenge in manufacturing. For the reduction of high cutting temperatures, micro-textured CVD diamond thick film cutting tools establish new potentials regarding the process productivity. The application of micro-textures allows a reduced contact area between chip and tool in order to decrease the generation of heat. Furthermore, a direct application of lubricant into the cutting zone is possible. The present study investigates the influence of micro-textured CVD diamond thick film cutting tools on the resulting process forces, chip formation as well as maximum cutting volumes during turning process. Part of the investigations was a variation of micro-texture trajectory with micro-textures parallel to the major cutting edge, perpendicular to the bisector of corner angle ε and curved along the cutting edge. The analyses showed that both positive and negative effects occur using micro-textures. The forces can be reduced by 14 % whereas the use of micro-textures leads to higher feed forces F f by 21 % as well as an additional notch effect in the micro-texture bottom.

关键词： CVD diamond thick film micro-texture Ti-6Al-4V turning

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