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13th International Conference on the technology of Plasticity, ICTP 2021

作者： Trân, Ricardo Kertsch, Lukas Marx, Sebastian Hebbar, Shreyas Psyk, Verena Butz, Alexander Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz09126 Germany Fraunhofer Institute for Mechanics of Materials IWM Wöhlerstraße 11 Freiburg79108 Germany

ISBN: (纸本)9783030753801

Manufacturing technologies for parts made from ultra-high-strength 7xxx series aluminum sheet material have been the focus of research in recent years. A promising approach is W-temper forming, where sheet material is cold formed after heat treatment. Conventional heat treatment routes are very time-consuming and inefficient. In this study, a new more efficient and industry-orientated transfer tool concept has been developed. Heating and cooling of the sheets take place in separate contact tempering stages, which allow superior heating and cooling rates in comparison to conventional methods. To analyze the influences of temperature rates and deformation on microstructure and mechanical behavior, thermo-mechanical experiments in a Gleeble simulator were carried out. The results prove the great potential of the transfer tool concept with inline heat treatment for series production. The process-dependent mechanical properties determine a suitable process window for the industrial application of the W-temper forming of the analyzed alloys. © 2021, The Minerals, Metals & Materials Society.

关键词： Industrial research

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Antibacterial Surface Protection using Electrical Discharge Machining with Zinc Tool Electrode for Medical Devices

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Procedia CIRP 2024年 125卷 278-283页

作者： Viet D. Bui André Martin Thomas Berger Philipp Steinert Andreas Schubert Chemnitz University of Technology Professorship Micromanufacturing Technology Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 09126 Chemnitz Germany

Electrical discharge machining (EDM), widely used to fabricate medical devices, is applicable for antibacterial surface protection. Silver, transferred from tool electrode or powder suspended in the dielectric to the modified layer during the EDM process, significantly enhanced antibacterial properties of the modified surface. However, bacterial resistance to silver, which was widespread in clinical, still posed challenges for the modified surfaces containing silver. Zinc, owing to its strong antibacterial effects and no challenge related to Zn-resistant bacteria hitherto reported in clinical, was therefore used as tool electrode material to modify Ti6Al4V surfaces during the EDM process. Discharge energies up to 170 µJ with different polarities were applied in the EDM milling process using deionized water-based dielectric fluid. Results show that discharge energy and polarity play a vital role in chemical composition and roughness of the modified surfaces as well as material removal rate and tool wear rate. The surfaces containing zinc contents up to 28 % can be generated. The use of a low energy generates zinc-rich surfaces with less micro-cracks. The EDM process using zinc tool electrode shows a promising potential for antibacterial surface modification of medical devices.

关键词： EDM Zinc electrode Medical device Antibacterial surface

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Developments in Powder Mixed EDM and its perspective Application for targeted Surface Modification 15

Developments in Powder Mixed EDM and its perspective Applica...

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15th CIRP Conference on Intelligent Computation in Manufacturing Engineering, CIRP ICME 2021

作者： Schubert, Andreas Bui, Viet D. Schaarschmidt, Ingo Berger, Thomas Martin, André Chemnitz University of Technology Professorship of Micromanufacturing Technology Reichenhainer Strasse 70 Chemnitz09107 Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 Chemnitz09126 Germany

Although widely studied over the few decades, there are conflicting theories on the discharge mechanisms of powder mixed electrical discharge machining (PMEDM). Additionally, the dielectric flow plays a vital role in the distribution of powder particles in the machining gap, which significantly affects the powder deposition to the modified surface. In this paper, the literature on PMEDM surface modification is thoroughly reported. The conflicting mechanisms and the effects of PMEDM main machining conditions, such as powder and electrical parameters on improving mechanical and antibacterial properties as well as biocompatibility of the surface, have been discussed. To verify the separation mechanism of the discharge in PMEDM, single discharge investigations have been performed when silver nano-powder is mixed into the hydrocarbon-based dielectric fluid to modify Ti6Al4V surfaces. Surface topography, chemical composition as well as the deposited silver content and distribution over the crater surface when using positive and negative polarities are analyzed and discussed. Current waveforms of PMEDM and EDM without powder at varying discharge energies as well as with and without ultrasonic vibration assistance are recorded and analyzed. For the transfer of fundamental results to a perspective application, CFD simulation is used to calculate the flow field of the dielectric fluid and analyze the velocity and distribution of the nano-powder within the working gap of a setup with internal flushing. The results show that PMEDM is a potential technology for machining medical devices with simultaneous antibacterial surface modification. © 2022 The Authors. Published by Elsevier B.V.

关键词： Titanium alloys

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Apparatus to measure wear of soft tissue induced by reconstruction plates – A preliminary study

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Procedia CIRP 2024年 125卷 290-295页

作者： Anas Ben Achour Allani Mohamed Hedi Uwe Teicher Günter Lauer Christian Bräuer Tom Alexander Schröder Fraunhofer Institute for Machine Tools and Forming Technology IWU 01187 Dresden Germany Oral and Maxillofacial Surgery Faculty of Medicine Carl Gustav Carus TU Dresden 01307 Dresden Germany Department of Oral and Maxillofacial Surgery Facial Plastic Surgery University of Rostock Schillingallee 35 18057 Rostock Germany

Mandibular reconstruction is a complex surgical procedure that aims to restore form and function. This procedure becomes necessary in cases where significant bone loss or defects occur due to medication-related osteonecrosis or severe cases of osteomyelitis, tumor resection, or congenital abnormalities. In the last decades, advancements in surgical techniques, materials, and technologies have greatly improved the outcomes of mandibular reconstruction. Nevertheless, complications such as the subsequent formation of large soft tissue wounds regularly occur after the successful treatment of these bone defects. These wounds occur as a result of the relative movements that naturally happen between the implant and the soft tissue, causing the soft tissue to wear away. However, the factors that promote or delay wear have not yet been conclusively clarified. In this work, a test bench was developed and evaluated to simulate naturally occurring movements between implant materials and soft tissue. Then, this test bench was used to compare the wear behavior of linear titanium plates with the behavior of titanium plates encased with bone cement (Palacos®) in a preliminary study. The friction coefficients for different movement patterns of the two surgical techniques were measured and the wear on the abdominal skin of pigs was examined. The results revealed that encasing the titanium plates with bone cement has advantages in terms of friction coefficients and wear for certain movement patterns.

关键词： Bio-based cooling lubricants tribology friction process forces tool wear

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Experimental validation of characteristic diagram- parameterization for environment-induced thermal interactions on machine tools in a climate chamber

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Procedia CIRP 2021年 99卷 63-68页

作者： Tharun Suresh Kumar Janine Glänzel Robert Tehel Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Str. 88 Chemnitz 09126 Germany

Thermal gradients created by environmental influences on machine tools cause considerable non-linear thermo-elastic deformations whether the machine is in operation or in idle mode. When a machine tool is subjected to changes in environmental influences such as ambient air temperature, velocity or direction, then flow (CFD) simulations are necessary to effectively quantify the thermal behavior between the machine tool surface and the surrounding air. The conventional two-step simulation procedure consisting of coupled CFD and thermo-elastic simulation is highly time-consuming especially when complex geometries are considered. Decoupling of CFD and thermo-elastic simulation can be achieved by introducing a Clustering Algorithm (CA) and Characteristic Diagrams (CDs) within the simulation workflow. Using training data obtained from a limited number of CFD simulations, the CDs can predict the heat transfer coefficients (HTCs) based on the parameterized environmental influences. This paper attempts to validate the experimental temperature and displacement readings obtained at selected positions on a machine tool using a wide range of metrological equipment such thermography camera, temperature and displacement sensors with the decoupling approach based on parameterized CDs. For investigation, the machine tool is positioned in a climate chamber, which facilitates the variation of environmental influences such as ambient temperature, flow velocity and flow direction. Initially, a precise coupled simulation model is created which is later on converted to a decoupled system using parameterized CDs.

关键词： Decoupling approach CFD-FE simulation Experimental validation Clustering Genetic algorithm

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Usage-based leasing of complex manufacturing systems: A method to transform current ownership-based into pay-per-use business models 55

Usage-based leasing of complex manufacturing systems: A meth...

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55th CIRP Conference on Manufacturing Systems, CIRP CMS 2022

作者： Alaluss, Mohaned Drechsler, Chris Kurth, Robin Mauersberger, Anton Ihlenfeldt, Steffen Marré, Michael Labs, Rainer Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz09126 Germany Institute of Mechatronic Engineering Technische Universität Dresden Helmholtzstr. 7a Dresden01069 Germany South Westphalia University of Applied Sciences Frauenstuhlweg 31 Iserlohn58644 Germany

Manufacturing technology with its cost- and resource-intensive manufacturing machines like machine tools, whose amortization often takes several years, is characterized by a high degree of individualization. Here, the need for increasingly complex as well as individualized products leads to the demand for high flexibility and resilience in complex manufacturing systems. The increasing uncertainty and volatility in the markets pose high economic risks for machine operators with ownership-based business models to enter new technologies. Consequently, this restrains the innovative and creative power of manufacturing companies. Although leasing models exist in various industry sectors like printing industry or compressed air supply, their implementation is still challenging due to the high degree of complexity regarding machine system, process, and services of the leasing product. In this paper, a novel method, with increased consideration of technical-technological aspects, to transform current ownership-based into usage-based business models like pay-per-use, is proposed. The resulting method also considers the pay-per-use readiness through an initial assessment of the existing manufacturing system. © 2022 The Authors. Published by Elsevier B.V.

关键词： agile production business models industry 4.0 machine tools manufacturing machines method pay-per-use perfomance-based contracting

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Exposure to industrial noise: Impacts on cognitive performance 50

Exposure to industrial noise: Impacts on cognitive performan...

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50th International Congress and Exposition of Noise Control Engineering, INTER-NOISE 2021

作者： Pereira, Luiz Henrique Mesa Casa Knöfel, Björn Troge, Jan Drossel, Welf-Guntram Klein, Marcel Hübelt, Jörn Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 Dresden01087 Germany Mittweida University of Applied Sciences Technikumplatz 17 Mittweida09648 Germany

ISBN: (纸本)9781732598652

Research on the relation between exposure to noise and cognitive performance inside industrial environments is not as broad as on office environments. For a better understanding of the specific industrial noise problems, 23 participants performed arithmetic tests inside a hemi anechoic room while they were exposed to a sequence of sound from five typical industrial noise sources. The subjects also classified how annoying they perceived the noise signals. The effects of noise on the arithmetic test's performance of the 23 participants was found on accuracy and on velocity, although the p-values of a Student t-test are comparable high. Dividing the subjects into a group of more noise annoyed resp. a group of less noise annoyed participants revealed significant influences of the presence of noise compared to an initial test without noise. The more annoyed subjects exhibit a drop of accuracy (-4%, p=0.017) while the less annoyed subjects increase significantly their velocity in the test (+15%, p=0.001). Subjects that evaluated noise as more annoying performed worse in a final arithmetic test (under silence) after being exposed to the noises, indicating a possible cumulative effect of noise on performance. The findings provide a better insight in the cognitive behavior of people who are exposed to industrial noise. Hence, the study will proceed with the specific noise analysis of single industrial workplaces. © INTER-NOISE 2021 .All right reserved.

关键词： Testing

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Effects of ultrasonic vibration on the silver deposition in powder mixed EDM for antibacterial surface modification 23

Effects of ultrasonic vibration on the silver deposition in ...

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23rd International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2023

作者： Bui, Viet D. Berger, Thomas Martin, André Harnisch, Karsten Döring, Joachim Bertrand, Jessica Schubert, Andreas Chemnitz University of Technology Institute for Machine Tools and Production Processes Professorship Micromanufacturing Technology Reichenhainer Str. 70 Chemnitz09126 Germany Otto-von-Guericke University Magdeburg Institute of Materials and Joining Technology Universitätsplatz 2 Magdeburg39106 Germany Otto-von-Guericke University Magdeburg Department of Orthopaedic Surgery Leipziger Str. 44 Magdeburg39120 Germany Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Str. 88 Chemnitz09126 Germany

ISBN: (纸本)9781998999132

Previous studies have demonstrated that silver nano-powder mixed electrical discharge machining (PMEDM) is a potential technique for concurrent ablative shaping medical implants and generating antibacterial layers on the surfaces. PMEDM modified surfaces with deposited silver offer excellent antibacterial properties along with very good biocompatibility. However, for medical applications, PMEDM is still facing challenges providing sufficiently uniform distribution of deposited silver and preventing spattered layers that might lead to delamination from the modified surface. It was indicated that ultrasonic vibration (UV) has remarkable effects on the fluid dynamics in the spark gap, which positively affect the silver distribution and reduce the generation of spattered layers. Consequently, in this study, a Ti6Al4V workpiece is vibrated with an ultrasonic frequency of 22.3 kHz and an amplitude of 2.5 μm during the PMEDM process. The effect of vibration direction in X and Z axis on the silver deposition is evaluated while discharge energy is varied up to 125 μJ. For comparative analyses also PMEDM without vibration assistance is investigated. Ti6Al4V hollow tool electrodes with an outer diameter of 3 mm and an inner diameter of 2.5 mm are utilised for internal flushing with a pressure of 4 bar. A hydrocarbon-based dielectric fluid is mixed with silver nanopowder at a concentration of 15 g/l. Results show that UV assisted PMEDM increases the content of deposited silver up to 1.7 times compared to PMEDM without vibration. UV with vibration in Z direction and pulse energies of 55 μJ and 125 μJ results in uniform silver distribution and significantly decreases spattered layer formation, whereas the use of vibration in X-direction leads to negative effects. By carefully selecting machining conditions such as vibration direction and amplitude, wall thickness of hollow tool electrode and powder concentration, PMEDM provides surfaces with promising characteristics for medical

关键词： Medical applications

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Software assisted clamping point classification and position optimization for the efficient flexibilization of carbody fixtures using mathematical geometry-based search algorithms

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Procedia CIRP 2021年 99卷 466-471页

作者： Rayk Fritzsche Robert Schaffrath Marcel Todtermuschke Head of group Assembly systems at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz 09126 Germany Scientific employee at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz 09126 Germany Head of dep. Assembly systems at Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz 09126 Germany

The fraunhofer iwu has been developed specialized clamping robots for production of different car-models on one fixture. One of the challenges with universal clamping of different components is the contact point between part and clamping device. For the optimization of the clamping contours, a software was developed with which the geometries of the clamping points can be automatically analyzed and classified. With target search criteria, the clamping position on the component can be changed so that the clamping contours are geometrically simplified. Thus, a huge reduction in the complexity of the flexible clamping device is possible.

关键词： Body in white Automated device design Analysis software Optimization Product flexibility

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Generative design in factory layout planning

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Procedia CIRP 2021年 99卷 9-14页

作者： Marian Süße Matthias Putz Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany

Planning and optimization of facility layouts have been investigated for decades and manifold approaches are applied for structuring and design of production layouts. However, results heavily depend on the experience and creativity of involved planning experts. Currently, complexity of planning processes constantly increases, e.g. due to further requirements of energy and media supply. Generative Design, hitherto mainly applied in component development, provides opportunities to cope with a much larger solution space and develop creative layout concepts. Thus, based on a structured overview on established planning methods, a concept and first results of factory layout planning with Generative Design are described.

关键词： Generative design Computational design Evolutionary design Factory planning Layout planning Literature search

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