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24th International ESAFORM Conference on Material forming, ESAFORM 2021

作者： Olivier, Marcel Heß, Raphael Gommeringer, Andrea Kern, Frank Herrig, Tim Bergs, Thomas Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University Campus-Boulevard 30 Aachen52074 Germany University of Stuttgart Allmandring 7b Stuttgart70569 Germany Fraunhofer Institute for Production Technology IPT Steinbachstraße 17 Aachen52074 Germany

ISBN: (纸本)9782870193020

Electrically conductive and thereby electrical discharge machinable ceramics may gain further relevance for tooling applications and in chemical industry. They combine high chemical and thermal durability with high hardness and strength. While these properties represent a significant advantage for application, they are a major challenge for conventional machining. Due to the thermophysical removal principle, wire electrical discharge machining (WEDM) is a suitable manufacturing process for hardness-independent machining and may broaden the use of ceramics especially in case of customized complex parts. Up to now, there are only a few investigations on WEDM of electrically conductive ceramics, especially with regard to the surface integrity and the influence of the EDM process on the mechanical properties. A previous study investigated the influence of different WEDM technologies on the surface integrity and the resulting load-bearing capacity of a zirconia-tungsten carbide (TZP-WC) ceramic. Based on this investigation, the heat flow in this ceramic composite was calculated with the use of a heat simulation model and compared with the analyzed rim zone, in order to predict a priori reliable process parameters. Furthermore, the wire electrical machinability and the bending strength of alumina-zirconia-tungsten carbide (ATZ-WC) composite ceramics with different fractions of the respective phases were investigated to identify the correlations and verify the simulation model. © ESAFORM 2021 - 24th Inter. Conf. on Mat. forming. All rights reserved.

关键词： Wire

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Time- And Cost-Efficient Specification and Evaluation of Manufacturing Changes through Iterative Information Acquisition 54

Time- And Cost-Efficient Specification and Evaluation of Man...

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54th CIRP Conference on Manufacturing Ssystems, CMS 2021

作者： Hermann, L. Weber, A. Beckers, A. Barth, S. Bergs, T. Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University Campus-Boulevard 30 Aachen52074 Germany FH Aachen University of Applied Science Bayernallee 11 Aachen52066 Germany Fraunhofer Institute for Production Technology Steinbachstraße 17 Aachen52074 Germany

The adaptation of established products and their components is a crucial process for companies to react to changing environments. To realize a component change, the corresponding manufacture must also be adapted. Often, a specific component change can be realized through alternative Manufacturing Changes, which must be specified and evaluated in relation to one other. A systematic approach to a timely and cost-efficient specification and evaluation of alternative Manufacturing Changes is therefore presented in this paper. The approach is based on an iterative information acquisition process, which generates the input for the specification and evaluation of Manufacturing Changes. © 2021 Elsevier B.V.. All rights reserved.

关键词： Specifications

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Modeling of the wet immersed tumbling process with the Discrete Element Method (DEM) 18

Modeling of the wet immersed tumbling process with the Discr...

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18th CIRP Conference on Modeling of Machining Operations, CMMO 2021

作者： Uhlmann, E. Fürstenau, J.-P. Kuche, Y. Yabroudi, S. Polte, J. Polte, M. Institute for Machine Tools and Factory Management IWF Technische Universität Berlin Pascalstr. 8-9 Berlin10587 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 Berlin10587 Germany CADFEM GmbH Pelikanstr. 13 Hannover30177 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. © 2021 Elsevier B.V.. All rights reserved.

关键词： Finite difference method

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Rule-based Decision Support for No-Code Digitalized Processes

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Procedia CIRP 2022年 107卷 258-263页

作者： Jimmy Chhor Vincent Fischer Fabian Kröppel Robert H. Schmitt Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University Campus-Boulevard 30 52074 Aachen Germany Modell Aachen GmbH Am Kraftversorgungsturm 5 52070 Aachen Germany Fraunhofer Institute for Production Technology IPT Steinbachstr. 17 52074 Aachen Germany

Digitalized processes offer various advantages: uniform information flow, traceability of process progress, and enhanced analyzability. While these represent initial benefits from the digitalization of the process, a recurring evaluation and optimization of the process are required to sustain and improve process efficiency. For both non-digitalized and digitalized processes, the challenges for process owners are comparable. However, for digitalized processes, convenient tools facilitate process modifications. Particularly no-code digitalized processes exploit the opportunity for quick and agile process adaption with low efforts but require a structured and systematic method to ensure a quality-driven approach. This paper conceptualizes a rule-based decision support model for process improvement that takes advantage of digital traces recorded during process execution of digitalized processes. On the one hand, process mining techniques support data analysis and assist the extraction of process performance indicators as precursors to predict low process performance. On the other hand, process experts compile a list of recommendations for action in workshops and interviews to counteract low process efficiency. The approach to rule-based decision support developed in the scope of this research merges these two dimensions and constitutes an assistive tool for the continuous improvement of digitalized processes. Initial results of the model in practical application support this assessment and demonstrate further research needs.

关键词： process mining decision support process digitalization no-code digitalization business process management

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Wear behaviour of various CVD diamond thick film specifications during turning Ti-6Al-4V

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Procedia CIRP 2021年 101卷 266-269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

Due to the specific mechanical and thermal properties of Ti-6Al-4V, such as its high heat resistance, the suitability of certain cutting materials is adversely affected. However, the high thermal conductivity and wear resistance of CVD diamond thick films provide the possibility for machining these materials. The present study investigates the wear behaviour of different CVD diamond thick film specifications at various cutting *** particular, differences in the process forces of 53% due to the CVD diamond thick film specifications as well as deviations in tool stability due to process parameter dependent cracks or wear progress were observed.

关键词： diamond tool titanium turning

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Teleoperation of an Industrial Robot using Public Networks and 5G SA Campus Networks

Teleoperation of an Industrial Robot using Public Networks a...

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IEEE International Conference on Robotic Computing (IRC)

作者： Jannik Rohde Olga Meyer Quy Luu Duc Christoph Jürgenhake Talib Sankal Roman Dumitrescu Robert H. Schmitt Competence Center DigITools for Production Fraunhofer Institute for Manufacturing Engineering and Automation IPA Stuttgart Germany Systems Engineering Fraunhofer Institute for Mechatronic Systems Design IEM Paderborn Germany Digital Infrastructures Fraunhofer Institute for Production Technology IPT Aachen Germany Heinz Nixdorf Institute University of Paderborn Paderborn Germany Laboratory for Machine Tools and Production Engineering WZL of RWTH Aachen University Aachen Germany

ISBN: (纸本)9781665472616

The next generation of cellular mobile communication standard 5G is considered to have more stable and secure communication links, low latency and higher flexibility which can be enablers for various new scenarios and applications. Teleoperation is the field that can benefit greatly from 5G technology. Demanding and mission-critical use cases such as telesurgery have challenging requirements like low latency and high reliability of the communication channel, which can be possibly met by 5G in the future. This work presents a 5G architecture for the teleoperation of an industrial robot over long distance. For this purpose three fraunhofer institutes were connected over public internet and 5G campus networks. Furthermore, this work describes the latency performance of the investigated teleoperation use case. The measurements in the experiment are performed with two 5G standalone (SA) networks and an edge cloud.

关键词： Cloud computing 5G mobile communication Service robots Mission critical systems Computer architecture Communication channels Reliability

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Concept for the reduction of non-value-adding operations in Laser Powder Bed Fusion (L-PBF)

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Procedia CIRP 2022年 107卷 344-349页

作者： Hajo Groneberg Rainer Horstkotte Marcel Pruemmer Thomas Bergs Frank Döpper University of Bayreuth Chair Manufacturing and Remanufacturing Technology Universitätsstraße 30 95447 Bayreuth Germany Fraunhofer Institute for Production Technology IPT Steinbachstraße 17 52074 Aachen Germany RWTH Aachen University Laboratory for Machine Tools and Production Engineering (WZL) Campus-Boulevard 30 52074 Aachen Germany Fraunhofer Institute for Manufacturing Engineering and Automation IPA Universitätsstraße 9 95447 Bayreuth Germany

In additive manufacturing with metallic base material, Laser Powder Bed Fusion (L-PBF) is an industrially established technology for tool-free production of complex and individualized components and products by applying material layer by layer. In addition to in-processing, the L-PBF process chain consists of several other process steps in pre- and post-processing. A holistic view of the additive manufacturing process chain shows that many process steps currently involve non-value-adding (NVA) operations and that there is generally great potential for reducing throughput times and costs. Due to the great importance of efficiency in industrial manufacturing process chains, this paper proposes a concept for analyzing the L-PBF process chain and deriving measures to eliminate NVA operations and increase the efficiency of value-adding (VA) operations. First, this paper presents a methodology for identifying VA and NVA operations that encompasses the entire chain. After the process mapping, the process steps are divided into sub-tasks to subsequently analyze them with regard to the level of automation. This analysis is the basis for selecting the appropriate automation strategy and optimizing the individual process steps by applying automation-aligned lean production methods to increase the proportion of VA operations. The potential for a significant increase in the productivity of the additive manufacturing process chain is demonstrated through systematic analysis and requirements-based optimization of the level of automation. The approach is structured in an adaptive manner so that, beyond the possibilities of lean production and automation, other optimization alternatives from further disciplines, such as digitization and networking, can be integrated.

关键词： Additive manufacturing AM Laser Beam Melting Laser Powder Bed Fusion L-PBF Process chain Process optimization Process recording Automation Automated handling Automation concepts Lean production

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Preparation of Papers for IFAC Conferences & Symposia: Adaptive fixture system for reducing machining distortion caused by residual stresses in milling

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IFAC-PapersOnLine 2022年第2期55卷 264-269页

作者： M. Landwehr R. Kalocsay C. Kolvenbach P. Ganser T. Bergs Fraunhofer Institute for Production Technology IPT Steinbachstraße 17 52074 Aachen Germany Innoclamp GmbH An der Glashütte 11 52074 Aachen Germany Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University Campus-Boulevard 30 52074 Aachen Germany

Machining distortion caused by residual stresses is one of the major challenges in the production of thin-walled monolithic parts, which are widely used in the aerospace industry. The relevant influencing factors include the selected process parameters, the machining sequence as well as the used fixture system. This paper presents an adaptive fixture system for reducing machining distortion caused by residual stresses in milling. To validate the advantage of this system, machining distortion experiments are conducted on monolithic parts made of Ti-6A1-4V using a conventional and the adaptive fixture system.

关键词： Machining distortion Residual stress Milling Ti-6Al-4V Fixture system

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Bioinspired active hemocompatible coating systems for mechanical circulatory support devices: when engineering meets nano and molecular technology

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Procedia CIRP 2024年 125卷 60-65页

作者： Martin Kohse Lena Witzdam Felix Jakob Alexander Boes Holger Mescheder Robin Day Oliver Grottke Ulrich Schwaneberg Cesar Rodriguez-Emmenegger Thomas Bergs Fraunhofer Institute for Production Technology IPT Steinbachstr. 17 52074 Aachen Germany DWI – Lebniz Institute for Interactive Materials e.V. Forckenbeckstraße 50 52074 Aachen Germany Department of Anesthesiology RWTH Aachen University Hospital Pauwelsstraße 30 52074 Aachen Germany Chair of Biotechnology RWTH Aachen University Worringerweg 3 52074 Aachen Germany Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University Campus Boulevard 30 52074 Aachen Germany

Industrial manufacturing is undergoing a biological transformation, which has become a growing part of current research in production engineering. The technologies involved help to translate innovative approaches into existing or novel medical devices. Currently, however, even the most advanced blood contacting medical devices fail to be sufficiently inert to blood, thus causing acute effects – coagulation, inflammation, embolism, stroke – as well as chronic ones – inflammation and chronic use of anticoagulants. We present the marriage of advanced molecular science, nanotechnology and advanced production engineering to improve the hemocompatibility of hemodynamic systems, such as artificial hearts. Our consortium has joined forces to develop nature-inspired coating systems that improve hemocompatibility, prohibit adhesion of bacteria and minimize the growth of dangerous large thrombi. We achieve this by (1) concealing the presence of the titanium surface, thereby minimizing the activation of inflammatory and coagulatory reactions, (2) locally inactivating those molecules that cause uncontrolled coagulation, (3) directing the blood to use its own fibrinolytic system to digest the clot and (4) introducing micro surface patterns that interfere with the flow near the surface generating shear, which in turn prohibits dangerous clots from growing. In vitro tests demonstrate considerable improvement in hemocompatibility.

关键词： hemocompatibility surface functionalization surface modification biological building blocks

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Parameter study on press hardened components with tailored properties

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IOP Conference Series: Materials Science and Engineering 2021年第1期1157卷

作者： M Nestler J Schönherr R Haase A Albert A Stoll V Kräusel Fraunhofer Institute for Machine Tools and Forming Technology Chemnitz Germany

In automotive industry, crash relevant parts are mainly manufactured by press hardening. An innovative process variant aims at producing components with tailored properties. For this purpose, the microstructural transformation is locally influenced to produce areas with lower strength. Hence, the forming tool is locally equipped with heating elements. Due to the non-uniform temperature distribution, the final part geometry results from a complex interaction of localized spring back, shrinkage and microstructure evolution. To achieve high geometric accuracy, a strong focus lies on the implementation of appropriate process parameters. A parameter study is performed in order to identify those process parameters, which mainly influence component distortion of a top hat profile. An automated test setup with a locally heated press hardening tool is used. As a result, the achieved hardness values and the geometric deviations are presented in dependence of the main influencing parameters.

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