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2022 Interoperability for Enterprise systems and Applications Workshops, I-ESA Workshops 2022

作者： Jaekel, Frank-Walter Knothe, Thomas Fraunhofer Institute Production Systems and Design Technology Pascalstr. 8-9 BerlinD-10587 Germany

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DEM Simulation of Abrasive Brushing Processes on Additively Manufactured Workpieces

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Procedia CIRP 2025年 133卷 203-208页

作者： Anton Hoyer Eckart Uhlmann 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

Brushing with bonded abrasives is a finishing process mainly used for deburring, edge rounding, and surface roughness reduction. The brushing tools consist of flexible polymer filaments embedded with abrasive grains, allowing them to adapt to complex workpiece shapes. However, interactions between filaments lead to complex motion, chipping, and wear behaviors, making it difficult to predict work results. The discrete element method (DEM) has been shown to be effective in simulating process forces, contact areas, and filament interactions on flat workpieces. Consequently, this article focuses on processing geometrically complex workpieces, particularly additively manufactured turbine fan blades (Ni-Cr-Co), using round brushes with bonded silicon carbide. First, a vectorized iterative method is introduced to generate artificial filament patterns, enhancing DEM simulation accuracy compared to state-of-the-art filament pattern models. Subsequently, dry brushing experiments are carried out on a fan blade feature demonstrator, aiming to achieve homogeneous roughness reduction. The qualitative analysis of the contact surface suggests that results from DEM simulations can reduce the need for costly technological investigations and prototypes.

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Laser beam welding of additive manufactured components: Applicability of existing valuation regulations

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Welding and Cutting 2022年第2期21卷 109-113页

作者： Jokisch, Torsten Gook, Sergej Marko, Angelina Üstündağ, Ömer Gumenyuk, Andrey Rethmeier, Michael Siemens Energy Global GmbH & Co Germany Fraunhofer Institute for Production Systems and Design Technology Berlin Germany Berlin Germany Berlin Germany Berlin Germany Berlin Germany

With additive manufacturing in the powder bed, the component size is limited by the installation space. Joint welding of additively manufactured parts offers a possibility to remove this size limitation. However, due to the specific stress and microstructure state in the additively built material, it is unclear to what ex-tent existing evaluation rules of joint welding are also suitable for welds on additive components. This is in-vestigated using laser beam welding of additively manufactured pipe joints. The welds are evaluated by means of visual inspection, metallographic examina-tions as well as computed tomography. The types of defects found are comparable to conventional com-ponents. This is an indicator that existing evaluation regulations also map the possible defects occurring for weld seams on additive components. © 2022, DVS Media GmbH. All rights reserved.

关键词： Welds

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Simulation of ultrasonic-assisted grinding for improved efficiency in hard-to-machine materials: A direct approach to analyze material removal mechanisms

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Procedia CIRP 2025年 133卷 209-214页

作者： Eckart Uhlmann Bernhard Gülzow Xinyu Zhang 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 application of ultrasonic superposition is utilized in industrial manufacturing to enhance the chip formation mechanisms, particularly when machining hard-to-machine materials. The institute for Machine Tools and Factory Management (IWF) systematically investigates the interactions between tool and workpiece during ultrasonic-assisted grinding of high-performance ceramics. To gain an in-depth understanding of the microscopic engagement conditions, these conditions are analyzed by simulation. For this purpose, a Python simulation tool based on a geometrical-kinematic modeling approach was developed to analyze the ultrasonic-assisted circumferential longitudinal grinding process. It was demonstrated that ultrasonic assistance leads to smaller and more uniform chip thicknesses which reduce grinding forces and minimizes tool wear. Also, it promotes brittle chip formation mechanisms and improves the efficiency of the grinding process compared to conventional machining. For further investigation, the simulation model was adapted to the transverse face grinding process. In this context, not only the circumferential surface but also the face surface of the grinding tool is engaged with the workpiece. Additionally, the penetration of the workpiece is no longer tangential with the rotational movement but perpendicular to the tool movement. Analogous to the results of the analysis of the circumferential longitudinal grinding process, the influences of ultrasonic excitation on the engagement conditions, particularly the resulting chip thickness and surface topography for the adapted process kinematics were determined and are presented in this paper.

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Impact of illumination technique on the detectability of irregularities in high-resolution images of visual in-situ process monitoring in Laser Powder Bed Fusion 13

Impact of illumination technique on the detectability of irr...

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13th CIRP Conference on Photonic Technologies, LANE 2024

作者： Merz, Benjamin Schmidt, Jonathan Poka, Konstantin Mohr, Gunther Polte, Julian Hilgenberg, Kai Bundesanstalt für Materialforschung Und-prüfung Unter den Eichen 87 Berlin12205 Germany Institute for Machine Tools and Factory Management IWF Technische Universität Berlin Pascalstraße 8-9 Berlin10587 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstraße 8-9 Berlin10587 Germany

The layerwise geometry build-up of additive manufacturing (AM) enables the possibility of in-situ process monitoring. The objective is the detection of irregularities during the build cycle, ensuring component quality and process stability. Focus of this work is the visual in-situ monitoring of the process of powder bed fusion with laser beam of metals (PBF-LB/M). Current state of the art visual monitoring systems for PBF-LB/M are limited by low resolution, allowing the detection of gross flaws. In this work a 65 Mpixel high-resolution monochrome camera is integrated into a commercial PBF-LB/M machine enabling a spatial resolution of approx. 17.2 μm/Pixel. The observed inhomogeneities are clustered into directly detectable irregularities, and indirectly detectable irregularities that can be inferred from the surface. In parallel, two different illumination techniques are realized in the process chamber and compared. The impact of the distinct illumination technique, direct light and dark field, on the identification of irregularities is evaluated. © 2024 The Authors.

关键词： Laser beams

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Cooling Capacity of Oil-in-Water Emulsion under wet Machining Conditions 19

Cooling Capacity of Oil-in-Water Emulsion under wet Machinin...

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19th CIRP Conference on Modeling of Machining Operations, CMMO 2023

作者： Nabbout, Kaissar Sommerfeld, Martin Barth, Enrico Uhlmann, Eckart Bock-Marbach, Benjamin Kuhnert, Jörg Institute of Process Engineering Otto-von-Guericke-University Magdeburg Universitätsplatz 2 Magdeburg39106 Germany Technische Universität Berlin Pascalstr. 8-9 Berlin10587 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 Berlin10587 Germany Fraunhofer Institute for Industrial Mathematics ITWM Fraunhofer-Platz 1 Kaiserslautern67633 Germany

Many industrial machining operations are carried out under wet machining conditions. Modelling and simulating fluid-structure-interactions and conjugate heat transfer are still a challenge nowadays. In this paper, temperature dependent heat transfer coefficients (HTC) h(T) are experimentally estimated for wet machining-like conditions in a jet cooling experiment. The transient temperature is thereby used to solve an Inverse Heat Transfer Problem for HTC function estimation. Determined HTC are applied as input in related jet cooling simulation using the Finite-Pointset-Method (FPM) to validate the modeling approach. Additionally, wet cutting simulations numerically highlight the influence of determined HTC h(T) on turning. © 2023 Elsevier B.V.. All rights reserved.

关键词： Cooling

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

Micro-texture dependent temperature distribution of CVD diam...

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6th CIRP Conference on Surface Integrity, CSI 2022

作者： Uhlmann, E. Schröter, D. Gärtner, E. Pascalstr. 8-9 Berlin10587 Germany Fraunhofer Institute For Production Systems And Design Technology Ipk Pascalstr. 8-9 Berlin10587 Germany Fraunhofer Institute For Machine Tools And Forming Technology Iwu Reichenhainer Str. 88 Chemnitz09126 Germany

Machining titanium alloys such as Ti-6Al-4V results in a high thermomechanical load on cutting tools and consequently short tool lifes. With respect to a necessary reduction of the resulting cutting tool temperatures, ultrashort pulse (USP) laser fabricated micro-textured rake faces offer direct supply of cooling lubricant into the cutting zone and lead to a reduced heat induction. As a result, micro-textured CVD diamond thick film cutting tools are also capable of machining high-performance materials due to reduced contact temperatures. In the scope of the research, the resulting temperature distribution for micro-textured rake faces will be compared under both dry and wet process conditions. Measurements show a reduction of the resulting cutting tool temperatures of ΔÏ't = 27.9 % using micro-textured cutting tools compared to non-textured cutting tools. A validated simulation provides valuable information about the contact temperatures enabling a specific development of the micro-texture geometry. As a result, a reduction of the contact temperature between chip and rake face by ΔÏ'T = 24.7 % was possible. © 2022 The Authors.

关键词： Turning

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Field demonstration of commercial PONs for edge-cloud-based industrial scenarios: requirements, use cases, and proofs of concept

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Journal of Optical Communications and Networking 2025年第7期17卷 590-600页

作者： Massimiliano Sica Behnam Shariati Hagen Hosl David Przewozny Sonke C. Niemann Moritz Chemnitz Paul Chojecki Johannes K. Fischer Ronald Freund Fraunhofer Institute for Telecommunications Heinrich-Hertz-Institut Einsteinufer 37 10587 Berlin Germany Fraunhofer Institute for Production Systems and Design Technology Pascalstraße 8-9 10587 Berlin Germany

Industrial networks and edge-cloud integration in manufacturing processes have gained significant attention due to the evolving requirements of Industry 4.0. Key demands include data-driven network management, multi-service support, and low-latency, high-bandwidth communications, all essential for the industry’s future. Standardization groups like the European Telecommunications and Standardization institute (ETSI) and several other research groups are working to quantify the requirements that industrial networks must meet to support Industry 4.0 applications. This study implements two ETSI use cases: Edge-Cloud-based Visual Inspection for Automatic Quality Assessment in production and Edge-Cloud-based Control of Automated Guided Vehicles. We experimentally validate the performance of the use cases by employing a physical testbed for edge-cloud-enabled manufacturing based on ETSI recommendations. We present a passive optical network testbed that connects multiple manufacturing floors to an edge-cloud for management, orchestration, and control. Our implementation features nanosecond-scale synchronization using precision time protocol, real-time network and energy monitoring for ubiquitous visibility, and multi-service capabilities through network slicing.

关键词： Manufacturing Real-time systems Fourth Industrial Revolution Monitoring Floors Network slicing Passive optical networks Industries Protocols Cloud computing

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Comparing the performance of a nested to a continuous evolution strategy with covariance matrix adaption for optimization of drilling EDM 15

Comparing the performance of a nested to a continuous evolut...

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

作者： Uhlmann, E. Streckenbach, J. Polte, M. Osmanovic, M. Schick, F. Institute for Machine Tools and Factory Management IWF Technische Universität Berlin Pascalstr. 8-9 10587 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstr. 8-9 10587 Germany

Electrical discharge machining (EDM) is a complex manufacturing process where the correlation of the individual process parameters is not fully known. When introducing new materials or complex, individual geometries in EDM, a satisfactory vector of parameters for the process must be found. This challenge is often encountered in the aerospace industry as well as in mold and tool making. One previously successful method to tackle this challenge is the stochastic optimization procedure Evolutionary Strategy (ES). Utilizing an appropriately chosen objective function, the search for a suitable vector of input parameters may be formulated as a mathematical minimization problem over the parameter space. The ES with a covariance matrix adaption (CMA) was utilized to sample from this parameter space in a stochastic manner. Examining the impact of the CMA within an ES is a promising way to gain better insight into the performance of ES. For this purpose, a vector of input parameters was optimized for a drilling EDM process with a comma and a nested comma ES with CMA. It was found that the comma ES led to a reduction in erosion duration tero of 38 % compared to the initially chosen parameters and the nested comma ES led to a reduction in erosion duration tero of 27 % compared to the same initial parameters. The additional information stored in the covariance matrix enables the ES to find a local optimum of the parameter vector faster and more consistently. This fact is verified by use of visualizations of the covariance matrix on a two-dimensional subspace. From these findings it can be concluded, that for the application of the ES to the optimization of EDM processes the CMA should be performed continuously over all generations as opposed to resetting this matrix after a number of generations. © 2022 The Authors. Published by Elsevier B.V.

关键词： Optimization

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Validation of different tungsten carbide-cobalt grades as tool electrode material for sinking EDM 15

Validation of different tungsten carbide-cobalt grades as to...

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

作者： Uhlmann, Eckart Bolz, Robert Polte, Mitchel Börnstein, Julian Technische Universität Berlin Institute for Machine Tools and Factory Management IWF Pascalstrasse 8-9 Berlin10587 Germany Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstrasse 8-9 Berlin10587 Germany

In sinking electrical discharge machining (EDM), tool electrode wear is crucial for an economical production. The tool electrode wear affects the process efficiency and determines the number of required tool electrodes for a specific machining process. Therefore, the relative tool wear, describing the relation of removed material volume between tool and workpiece electrode, needs to be minimised. The tool wear characteristics in sinking EDM depend strongly on EDM processing parameters and the applied electrode materials. Especially in micro-EDM, a significant increase of relative tool wear is representative. Because of its thermophysical properties tungsten carbide-cobalt (WC-Co) is a suitable material for the application as sinking EDM tool electrode. The economical production of WC-Co form electrodes for EDM sinking is enabled by recent advancements in precision milling of hard materials. Due to non-existent research on which composition of WC-Co is most advantageous for the application as sinking EDM tool electrode material, previous investigations have been intensified to describe correlations between material properties, EDM processing parameters and EDM processing results concerning material removal rate and relative tool wear. Therefore, various WC-Co grades with differing grain size and cobalt content were analysed in sinking EDM experimental studies. It was observed that the factor grain size showed an ambiguous effect concerning the process results. An increasing cobalt content led to a reduction of relative tool wear, which can be explained by the microstructure of the cobalt binder phase with its higher electrical conductivity. The WC-Co grades with beneficial EDM processing results have been further investigated in EDM parameter studies with differing tool electrode geometries. The experimental results concerning relative tool wear, with a minimum of 3 % for macro- and 5 % for micro-sized geometries, proved the suitability of specific WC-Co compositions

关键词： Electrodes

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