Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    PowerGrasp: Development Aspects for Arm Support Systems
    ( 2022)
    Goppold, J.-P.
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    Kuschan, J.
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    Schmidt, H.
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    Krüger, J.
    Exoskeletons can support workers on physically demanding tasks, but in industry they lack of acceptance. This contribution gives an insight into design aspects for upper body exoskeletons, especially how active exoskeletons for industrial applications differ from military and medical use-cases. To overcome typical rigid exoskeleton problems, we suggest the use of modular soft-exosuit support systems and therefore checked different types of soft actuation principles for their eligibility for the use on upper body joints. Most promising approach is using two-layered actuators sting of robust fabric with embedded rubber tubes as pressure chambers. By inflating the tubes, it is possible to vary the stiffness of the chambers, which can be effectively used to generate assisting forces and moments at human joints (shoulder, elbow, wrist, finger).
  • Publication
    Validation of Immersive Design Parameters in Driving Simulation Environments
    ( 2021)
    Lyga, Yvonne
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    Lau, Merle
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    Brandenburg, Elisabeth
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    Stark, Rainer
    Driving simulators are used for the prospective validation of technical systems in the automotive sector. The design of simulation environments can affect drivers and should be considered in investigations of driver-vehicle interactions. The aim of this research is to minimize the gap between driving simulators and real car studies by integrating immersive parameters into simulated driving environments. Stereoscopy, surround sound and motion feedback were analyzed with regard to driver behavior and experience and were then compared to data of a real drive from a previous investigation. The authors conducted a study with N = 48 participants performing a dual-task scenario in a driving simulator. Results reveal significant effects of immersive design parameters on gaze behavior and mental workload. Findings provide guidance for an efficient and cost-effective development of driving simulation environments.
  • Publication
    Development of a Conceptual Understanding of the term Technological Capability
    ( 2021)
    Hecklau, Fabian
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    Kidschun, Florian
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    Kohl, Holger
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    Hizal, Gamze Gül
    The term "technological capability" has been studied for almost 40 years. It is an important component of technology strategy that contributes to the success and strengthening of organizations competitiveness. There are numerous attempts to define the term in the literature, but it is always used in different contexts. Thus, the definition of technological capability varies depending on the researcher's perspective and objectives. Therefore, the main objective of this research is to develop an own definition and interpretation of the term technological capability. To this end, an extensive literature review will be conducted to examine the basic concepts and management areas of technological capability and to analyze the individual definitions of the term. The subsequent goal is to derive an understanding of what technological capability is in terms of research and technology organizations.
  • Publication
    Sensor integration in hybrid additive manufactured parts for real-time monitoring in turbine operations
    ( 2021)
    Uhlmann, Eckart
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    Polte, Julian
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    Kersting, Robert
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    Brunner-Schwer, Christian
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    Neuwald, Tobias
    Real-time monitoring of operation conditions such as tempeatures and vibrations enables efficiency enhancement for maintenance tasks. In energy industry monitoring of critical components such as turbine blades is essential for the operation safety. But the effective recording of critical process data is a challenging task due to the extreme operating conditions. With a hybrid processing approach combining two additive manufacturing technologies new classes of self-monitoring components become possible allowing data acquisition directly inside the component. Using the example of a turbine blade, the hybrid process chain is described. The turbine blade blank is produced via Laser Powder Bed Fusion (L-PBF) with channels for the integration of high temperature sensors. After integration cavities were closed by Laser Directed Energy Deposition (L-DED) followed by classical milling operations for part finishing. The data acquisition is integrated in state-of-the-art product l ifecycle monitoring (PLM) software to create a digital twin. Evaluation shows that temperature could be successfully monitored at conditions of Π= 550°C.
  • Publication
    Effects on part density for a highly productive manufacturing of WC-Co via laser powder bed fusion
    ( 2021)
    Polte, Julian
    ;
    Neuwald, Tobias
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    Gordei, Anzhelika
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    Kersting, Robert
    ;
    Uhlmann, Eckart
    The additive manufacturing of parts made from difficult-to-weld materials through the usage of preheating temperatures of up to Î0 ⤠500 °C is enabled by newest L-PBF machine tools, such as the RenAM 500Q HT from the company RENISHAW PLC, Wottun-under-Edge, UK. This work aims to delevop processing parameters for the dense and crack-free manufacturing of tungsten-carbide cobalt (WC-Co) via this off-the-shelf machine tool. Therefore the laserpower and scanning speed were varied between 80 W ⤠PL ⤠350 W and 140 mm/s ⤠vS ⤠650 mm/s respectively. Furthermore the influence of a continuous and pulsed laser mode was analysed. A focus was set on the identification of parameters that enable a highly productive manufacturing while maintaining a high part density. A parameter set for relative density rel. > 94 % and a buildup rate v = 0.59 mm3/s was developed.
  • Publication
    Service Modelling Language Applied for Hyper Connected Ecosystem
    ( 2021)
    Jäkel, Frank-Walter
    ;
    Zelm, Martin
    ;
    Chen, David
    The paper elaborates the application of service modelling language for hyper-connected ecosystems. A specific target is to demonstrate the use of ISO 19440 standard together with a set of specialized service modelling constructs developed in the scope of CEN TC310/WG1. It presents a conceptual use case to model a 'Matching Service' and the service system required to provide the Matching Service in a service ecosystem. The purpose of this study is to test and demonstrate the use of a service modelling language related to ISO19440:2020 to describe in a formal and systematic way a service and its needed service system at business level for communication and validation. The paper first presents the motivation of the study and recalls related works. The service modelling language and the background of this work are discussed. The Matching service use case will be presented in detail and the concluding summary as well as some outlooks are given at the end of the paper.
  • Publication
    Reduction of erosion duration for electrical discharge drilling using a nature analogue algorithm with nested strategy types
    ( 2021)
    Uhlmann, Eckart
    ;
    Polte, Mitchel
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    Streckenbach, Jan
    ;
    Osmanovic, Mirsad
    The required high economic efficiency, combined with the corresponding high quality demands, in the aerospace industry as well as in mould and tool making, motivate the necessity of finding suitable parameter combinations for the process of electrical discharge machining (EDM), e.g. when introducing new materials. To counteract this, various methods are being investigated in research for the optimisation of EDM. One new method is the stochastic optimisation procedure evolution strategy (ES). Due to its metaheuristic approach, this optimisation method is excellently suited for very complex processes in which the interrelationship of the individual influencing variables is not known. This publication presents the results of the investigation of the suitability of the ES optimisation method using the example of electrical discharge drilling. For this purpose, two nested ES-types were investigated. The electrode materials used were brass for the tool and stainless steel X5C rNi18-1 for the workpiece. As a result, the erosion duration could be reduced by 30 %. This investigation forms the basis for the use of nested ES types in electrical discharge drilling.
  • Publication
    Particle contact conditions for cutting edge preparation of micro-milling tools by the immersed tumbling process
    ( 2021)
    Uhlmann, Eckart
    ;
    Polte, Julian
    ;
    Kuche, Yves
    ;
    Landua, Fabian
    For increasing tool life and cutting length of micro-milling tools the cutting edge preparation was successfully established. Using the immersed tumbling process, a reproducible cutting edge preparation with constant cutting edge radii as well as low chipping of the cutting edges can be realised. For a profound understanding of the preparation process and the process mechanisms further knowledge about the particle interactions with cutting tools as well as the particle flow mechanisms needs to be obtained. In this investigation the preparation process of micro-milling tools was analysed and the contact-mechanisms as well as the resulting pressures were investigated by simulation studies. Using the discrete element method (DEM) with the software ROCKY DEM from the company ESSS, Florianópolis, Brasil, the immersed tumbling process could be modelled and particle contacts, particle traces as well as particle interactions with the micro-milling tool can be visualized. Especially the particle-tool interactions were more accurately investigated by analysing the stresses and particles shear work as well as correlations between these parameters to prove the comparability between the process simulation and the real preparation process.
  • Publication
    Simulation and compensation of the thermal behaviour of industrial robots
    ( 2021)
    Uhlmann, Eckart
    ;
    Polte, Julian
    ;
    Mohnke, Christian
    Industrial robot systems offer a flexible, adaptable basis due to their kinematics and their mobility. An influencing variable, which is particularly relevant for processes with long process times tP, is the thermal heating and the associated thermal drift ÎAPt of the tool center point. The maximum deviation from the actual nominal position can reach up to ÎAPt = 1.5 mm. In the investigations, a simulation model for an industrial robot was created and the thermal behaviour was mapped. With this model, the thermal error ÎAPt within the working area can be determined as a function of the current position X and temperature Ï. These data can be used for a targeted correction of the robot path. With the correction by the compensation model the amount of drift for real milling processes could be reduced to a value of ÎAPt = 0.042 mm. The results can help to reduce the influence of thermal heating and the associated thermal drift ÎAPt of the TCP without using cost-intens ive measures with additional hardware and software on external computers for compensating the errors.
  • Publication
    Photocatalytic effect of TiO2-coated surfaces on the pathogenic microorganisms E.coli and S.aureus
    ( 2021)
    Uhlmann, Eckart
    ;
    Hein, Christoph
    ;
    Brehmer, Annika
    The use of titanium dioxide as a strong photocatalytic substance can have a large effect in combating the spread of pathogens through heavily contaminated surfaces. For this purpose, various materials, such as metal, glass, and polymer were coated with rutile- and anatase-rich titanium dioxide by sol-gel method. The contact angle and photocatalytic activity of the coated surface were measured under UV irradiation. The anatase-rich titanium dioxide showed higher photocatalytic activity, which further increased with the coating thickness. The process temperature had an effect on the photocatalytic activity due to the temperature-dependent conversion of anatase to rutile crystal conformation. The coated surfaces had strongly reduced contact angles compared to the uncoated material. In particular, the anatase-rich surfaces resulted in superhydrophilic properties. Photocatalytically induced antibacterial activity against pathogenic microorganisms in liquid environments was d emonstrated, especially for gram-negative Escherichia coli bacteria.