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

作者： Uhlmann, E. Polte, M. Streckenbach, J. Dinh, N.C. Börnstein, J. Wolf, C.-S. Camin, B. Institute for Machine Tools Factory Management IWF Technische Universität Berlin Germany Fraunhofer Institute for Production Systems and Design Technology IPK Germany Institute for Materials Science and Technology Chair of Metallic Materials Technische Universität Berlin Germany

ISBN: (纸本)9780995775176

The production of components for automotive and aerospace industry by conventional machining is still limited by hardness and strength of the workpiece materials. Electro-discharge drilling is used for machining electrically conductive materials without any limitation due to mechanical properties. Electro-discharge drilling causes debris in the working gap, which leads to arcs and short circuits on the lateral surface with negative effects on processing results and process duration. Due to these arcs and short circuits limited drilling depth, increased tool wear, conicity of boreholes and process instabilities are still challenges in electro-discharge drilling. In this work, a new approach for passivation of the tool electrode material by oxidation is shown. Different oxidation processes for tool electrodes made of brass were applied and analysed. Surface modified tool electrodes were used for electro-discharge drilling of Elmax, SuperClean from the company VOELSTAPINE AG, Linz, Austria. The investigation was carried out on the machine tool AGIETRON Compact 1 from the company AGIE SA, Losone, Switzerland, for machining of through holes with a depth of t = 33.5 mm using different surface modified tool electrodes with a diameter of d = 0.8 mm. First results show a reduction of the erosion duration by 20 % for the application of thermally oxidized brass. The investigation of different defined oxide layer thicknesses and electrical resistances for specific applications are part of this ongoing work. This work is funded by the German Research Foundation (DFG). Copyright © Proceedings of the 20th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2020. All rights reserved.

关键词： Oxidation

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Numerical investigation on the process behavior of a closed-loop internal cooling system for turning operations

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Procedia CIRP 2021年 102卷 73-78页

作者： E. Uhlmann P. Meier Technische Universität Berlin Institute for Machine Tools and Factory Management (IWF) Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstr. 8-9 10587 Berlin Germany

The development of sustainable manufacturing processes and the associated reduction of operating materials such as cooling lubricants represent key focuses on recent production technology. Thus, a novel tool system with a closed-loop internal cooling system for turning operations is presented in this study. The system design is based on numerical investigations of the heat flow Q⋅ with consideration of the thermomechanical load of the cutting tool and flow characteristics of the cooling fluid. The process behavior of the proposed system shows a significant dependence of the flow rate V⋅ and tool thickness t T in terms of tool temperature reduction Δθ T .

关键词： Turning Cooling Sustainable manufacturing

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Micro-texture trajectory dependent pressure distribution of CVD diamond thick film cutting tools during turning of Ti-6Al-4V

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Procedia CIRP 2021年 102卷 49-54页

作者： E. Uhlmann D. Schröter Technische Universität Berlin Institute for Machine Tools and Factory Management (IWF) Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstr. 8-9 10587 Berlin Germany

To counteract the high thermomechanical load during turning Ti-6Al-4V, an advancement of tool geometries is necessary. Based on simulative and empirical analysis, the present study investigates the process behaviour of micro-textured CVD diamond cutting tools. Different micro-texture trajectories determine influence of the microstructure on the stress levels, pressure distributions and adhesive wear. Compared to non-textured cutting tools, a cutting force reduction of 12.8 % determined empirically and 19.5 % determined simulatively with simultaneous displacement of the principal stress results using micro-textures. Based on simulatively calculated process forces and pressure distributions an evaluation of tool stability and adhesion tendency is possible.

关键词： diamond tool texture finite element method (FEM) titanium turning

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Prediction of temperature distribution in diamond cutting tools during machining Ti-6Al-4V

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Procedia CIRP 2021年 102卷 37-42页

作者： E. Uhlmann D. Schröter V.H. Wohlfahrt Technische Universität Berlin Institute for Machine Tools and Factory Management (IWF) Pascalstr. 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstr. 8-9 10587 Berlin Germany

The high thermal conductivity and wear resistance of CVD diamond provide potential for the machining of Ti-6Al-4V. By predicting thermomechanical loads, simulations can provide information about the usability of these cutting materials. However, the occurring shear chip formation within the cutting process leads to unsteady contact conditions. Therefore, a computationally intensive long-term transient simulation is necessary for precise prediction of tool temperatures. In this respect, a user-subroutine has been developed, allowing a high-resolution long-term simulation with acceptable computing time. By experimental investigations and validation of simulated results, a modelling of temperature distribution within the cutting tool is possible, providing valuable information regarding the contact temperatures.

关键词： titanium diamond tool turning temperature

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Harmonization of Heterogeneous Asset Administration Shells

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Procedia CIRP 2022年 107卷 95-100页

作者： Nikolaos-Stefanos Koutrakis Varun Gowtham Wenzel Baron Pilar von Pilchau Thomas Josef Jung Julian Polte Jörg Hähner Marius-Iulian Corici Thomas Magedanz Eckart Uhlmann Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstr. 8-9 10587 Berlin Germany Fraunhofer FOKUS Kaiserin-Augusta-Allee 31 10589 Berlin Germany University of Augsburg Am Technologiezentrum 8 86159 Augsburg Germany Robert Bosch GmbH Robert-Bosch-Campus 1 71272 Renningen Germany Technische Universität Berlin Institute for Machine Tools and Factory Management (IWF) Pascalstr. 8-9 10587 Berlin Germany

In the era of digital transformation of the manufacturing and process industry, heterogeneity of assets is one of the most challenging issues towards digitally integrating components within the Industrial Internet of Things. In this context every participant relies on its proprietary digitalization approach envisioned by Plattform Industrie 4.0. To consolidate these heterogeneous data exchange interfaces, e.g. communication protocols, data formats etc., an intermediate step of harmonization is required. Our contribution provides an architecture based on the Asset Administration Shell standard to bring heterogeneous Cyber-Physical-systems together. We illustrate the functionality through an abstract use-case.

关键词： Asset Administration Shell Digital Twin Virtual Sensor Sensor Networks IIoT I4.0 MQTT OPC UA

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Simulation of metal cutting with cutting fluid using the Finite-Pointset-Method

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Procedia CIRP 2021年 101卷 98-101页

作者： Eckart Uhlmann Enrico Barth Tobias Seifarth Maximilian Höchel Jörg Kuhnert Almut Eisenträger Institute for Machine Tools and Factory Management (IWF) Technische Universität Berlin 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

Despite the common use of cutting fluids in metal cutting, most simulations of these processes only consider dry conditions. This is largely due to limitations in conventional simulation methods, such as the Finite Element Method (FEM), regarding fast changing computational domains. In this paper, a simulation model of metal cutting with cutting fluid based on the Finite Pointset Method (FPM) is presented. This approach allows to simulate the Fluid-Structure-Interactions (FSI) within the same simulation method. For different orthogonal turning processes, the simulations are compared with experiments for dry and wet conditions. The simulation results illustrate the cooling effect numerically.

关键词： Simulation Fluid Turning

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Pressure conditions during the immersed tumbling process

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Procedia CIRP 2021年 101卷 198-201页

作者： E. Uhlmann J. Polte M. Polte Y. Kuche Institute for Machine Tools and Factory Management (IWF) Technische Universität Berlin Pascalstraße 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstraße 8-9 10587 Berlin Germany

An approach to improve the tool wear behaviour of milling tools made of cemented carbide is a defined cutting edge preparation usingthe immersed tumbling process. One significant factor that influences cutting edge preparation is the effective pressure generated by the relative movement of the cutting tools and the abrasive particles. However, the development and influence of the process pressure has been discussed almost exclusively based on machining and preparation results. For a profound process understanding a wireless force measurement system was designed and the pressure forces of two media were examined. The influences of the used lapping media, the velocityas well as the depth of immersion using a simplified linear movement were analysed. The results provide information about the pressure conditions that change in the real process.

关键词： Cutting edge Finishing Force Measurement

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Boron-doped monocrystalline diamond as cutting tool for temperature measurement in the cutting zone

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Procedia CIRP 2021年 101卷 258-261页

作者： E. Uhlmann J. Polte M. Polte T. Hocke Institute for Machine Tools and Factory Management (IWF) Technische Universität Berlin Pascalstraße 8-9 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology (IPK) Pascalstraße 8-9 10587 Berlin Germany

Ultra-precision machining is a key technology for manufacturing optical surfaces in a broad range of automotive and aerospace applications. At the state of the art, no precise methods for analysing the temperatures in the cutting zone of a monocrystalline diamond tool are available. Precise cutting temperatures are required for a detailed analysis of the wear behaviour. High response times and low measurement accuracies are still challenges. In this work, a new approach for a precise temperature measurement using boron-doped diamonds is shown. The sensor properties of boron-doped diamonds were analysed and experimental investigations to show the suitability were carried out. First results show a great potential as measurement method for real time temperatures during the cutting process.

关键词： temperature sensor diamond tool measurement system ultra-precision machining

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Holistic Concept Towards a Reference Architecture Model for Predictive Maintenance

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Procedia CIRP 2021年 104卷 1430-1433页

作者： Eckart Uhlmann Julian Polte Nikolaos-Stefanos Koutrakis Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstraße 8-9 10587 Berlin Germany Institute for Machine Tools and Factory Management (IWF) Technische Universität Berlin Pascalstraße 8-9 Berlin 10587 Germany

In the era of digital transformation of factories, one of the most challenging applications of the Industrial Internet of Things (IIoT) is predictive maintenance. This paper presents a holistic concept for predictive maintenance together with a reference architecture that includes data acquisition on the sensor level, edge computing and digital twin applications. For that purpose, condition-based maintenance, lifecycle monitoring and digital assistance systems are integrated to develop application-specific digital twins based on the proposed architecture, integrating heterogenous data sources in order to enhance the accuracy of the machine learning models. The concept is illustrated through an experimental use case.

关键词： Analytics Reference Architecture Digital Twin Predictive Maintenance IIoT Machine Learning

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Dry-ED milling of micro-scale contours with high-speed rotating tungsten tube electrodes

Dry-ED milling of micro-scale contours with high-speed rotat...

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20th CIRP Conference on Electro Physical and Chemical Machining, ISEM 2020

作者： Uhlmann, E. Perfilov, I. Yabroudi, S. Mevert, R. 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

This paper presents machining results for dry-ED milling of micro-scale contours by use of a new machine tool, including a relaxation generator, designed for dry-EDM. To implement the dry-ED milling process tungsten tube electrodes were used. The gas is injected through the tubular tool electrode under high pressure. Additionally, a high-speed EDM spindle was used to overcome process instabilities and increase the material removal rate due to better flushing conditions. Further, fluid simulations of the flushing conditions are presented in this paper. It is found that the use of gaseous dielectrics enables much better machining results in terms of shape accuracy and tool wear. The simulations provide new insights in the flushing conditions when using gaseous dielectrics. The calculated fluid flow pattern shows a great agreement with the observed depositions of reattached molten material on the tool and workpiece surface. The results presented as well as the hardware introduced enable the industrial application of dry-EDM for the first time. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the scientific committee of the ISEM 2020

关键词： Computational fluid dynamics

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