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Constructive compensation of the thermal behaviour for industrial robots

IOP Conference Series: Materials Science and Engineering 2021年第1期1140卷

作者： Eckart Uhlmann Julian Polte Christian Mohnke Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstraße 8-9 10587 Berlin Germany Institute of Machine Tools and Factory Management Pascalstraße 8-9 10587 Berlin Germany

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, is the thermal heating and the associated thermal drift of the tool center point. The maximum deviation from the actual nominal position can reach up to ΔAPt = 1.5 mm. Currently, there are no procedures and methods established in practice which compensate the effects of thermal drift without expensive calibration measures and system downtime. In these investigations a system was developed which allows the reduction of thermally induced displacement by using controlled heating elements. The aim is to keep the entire robot system at a permanent, balanced temperature level. The heating elements are adapted to the geometry of the respective axis and heat the material to a temperature θ close to the steady state. A comparison of the drift through the heating system with the error occurring in normal operation shows that the drift of the heating system is comparable with the drift of normal heating. With the heating mats, a thermally induced error of ΔAPt = 0.234 mm can be generated within t = 20 min. While normal heating requires up to t = 600 min. The achieved error deviation of the drift of the self-heating to the heated variants is with ΔAP = 0.04 mm only minimal. The results can help to reduce the influence of thermal heating and the associated thermal drift of the TCP without using cost-intensive measures with additional hardware and software on external computers for compensating the errors.

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Multi-Material Additive Manufacturing – Recycling of binary Metal Powder Mixtures by Screening

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Procedia CIRP 2020年 93卷 50-55页

作者： Max Horn Lena Prestel Matthias Schmitt Maximilian Binder Georg Schlick Christian Seidel Gunther Reinhart Fraunhofer Research Institution for Casting Composite and Processing Technology IGCV Beim Glaspalast 5 86153 Augsburg Germany Department of Applied Sciences and Mechatronics University of Applied Sciences Munich Lothstr. 34 80335 Munich Germany Institute for Machine Tools and Industrial Management of Technical University of Munich Boltzmannstr. 15 85748 Garching n. Munich Germany

Multi-material additive manufacturing by laser powder bed fusion enables arbitrary material composition in components and thus opens new design possibilities. During the manufacturing process utilized powders are mixed and arising cross-contaminations are a hindrance for powder reuse. This paper investigates the possibility to process binary metal powder mixtures of different particle size distributions, which can be sorted and recycled by screening. Two different material combinations are processed over three multi-material manufacturing cycles and powder purities in the range of parts per thousand foreign particles can be achieved. Furthermore, material flow is calculated and general applicability of the recycling process is evaluated.

关键词： Multi-material Additive Manufacturing Laser Powder Bed Fusion Recycling Reuse Sieving Powder Separation

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Sandwich manufacturing with foam core and aluminum face sheets - A new process without rolling 10th

Sandwich manufacturing with foam core and aluminum face shee...

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10th International Conference on Porous Metals and Metallic Foams, MetFoam 2017

作者： Hohlfeld, Jörg Hipke, Thomas Schuller, Friedrich Fraunhofer Institute for Machine Tools and Forming Technology Reichenhainer Strasse 88 Chemnitz09126 Germany Havel metal foam GmbH Am Suedtor 1 b Brandenburg an der Havel14774 Germany

ISBN: (纸本)9783035712315

The manufacturing processes for sandwiches made with aluminum or steel sheets are differentiated by their various melting ranges. Sandwiches with aluminum face sheets have recently been produced using the so-called AFS technology, which includes a rolling process. However, it is desirable to avoid rolling for cost reduction and allow quick and flexible responses to the customer needs, the manufacturing process needs to be redesigned. This publication introduces a sandwich manufacturing approach that modifies the production of sandwiches with aluminum face sheets. The necessary process steps as well as the test results of foaming and peeling tests are presented. For a successful implementation of the approach it has been demonstrated by a sandwich production with a surface dimension of 1.500 mm x 1.000 mm. © 2018 Trans Tech Publications, Switzerland.

关键词： Cost reduction

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forming 4.0: Smart machine components applied as a hybrid plain bearing and a tool clamping system

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Procedia Manufacturing 2019年 27卷 65-71页

作者： R. Kurth R. Tehel T. Päßler M. Putz K. Wehmeyer C. Kraft H. Schwarze Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 09126 Chemnitz Germany Berg & Co. GmbH Gildemeisterstraße 80 33689 Bielefeld Germany Technical University Clausthal Institute of Tribology and Energy Conversion Machinery Leibnizstraße 32 38678 Clausthal-Zellerfeld Germany

Higher process reliability as well as detailed information about the machine condition are necessary requirements for the manufacturing of complex geometric shapes with simultaneous increase of the machine availability and output rate. By implementing smart machine components it is possible to solve central challenges focusing on the investment-intensive field of forming technology. These components gather and evaluate machine and process data on decentralized spots with certain integrated sensors. Within this paper the potential benefits of those smart machine components are demonstrated using the example of an intelligent hybrid plain bearing and a smart tool holder. Focusing on the damage prevention of plain bearings, a load controlled journal bearing combining hydrodynamic and hydrostatic characteristics has been developed and tested by simulation. In addition, a smart hydraulic tool holder for upper dies has been successfully tested by simulations and experiments in order to investigate and demonstrate the potential for using the monitored clamping characteristics to increase the process transparency and the condition of the tool holder. As a result these smart machine components can be used additionally for a significant improvement of industry 4.0 tools such as digital twins of both process and machine.

关键词： industry 4.0 sensor integration plain bearing journal bearing tool clamping condition monitoring smart components process monitoring

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Numerical and Experimental Investigation of Thermoplastics in Multi-Axis forming Processes

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Procedia CIRP 2019年 85卷 96-101页

作者： Klaus Dröder Bernd-Arno Behrens Florian Bohne Alexander Chugreev Henrik Schulze Birk Wonnenberg Technische Universität Braunschweig Institute of Machine Tools and Production Technology Langer Kamp 19b 38106 Braunschweig Germany Institute of Forming Technology and Machines Leibniz Universität Hannover An der Universität 2 30823 Garbsen Germany

Process planning for multi-axis forming presses is a particular challenge. This process provides the option to actively influencing the material flow in the forming process by defining a six dimensional tool motion path and the tool velocity. By comprehending this interaction, it is possible to control and thereby tailor the induced local material properties of the workpiece. Experiments were conducted with a multi-axis press, which is based on a Stewart platform. A simple plane workpiece geometry is chosen to analyse the flow behaviour and the temperature evolution of the glass mat thermoplastics (GMT) during the forming process. Subsequently, a numerical simulation of the multi-axis forming process is carried out and validated with the experimental data. The numerical analysis focuses on the material modelling as well as the prediction of the flow characteristics. Regarding material modelling of GMT, an extensive material characterization is performed to describe the flow behaviour. A prediction of the flow behaviour of GMT with reference to tool motion is enabled. For the FE simulation the element-free Galerkin method (EFG) is applied for modelling the fluid structure interaction and adaptive procedures.

关键词： forming Fiber reinforced plastic Temperature Kinematic Finite element methode (FEM)

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Smart materials for smart production – a cross-disciplinary innovation network in the field of smart materials

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Procedia Manufacturing 2018年 21卷 197-204页

作者： W.-G. Drossel F. Meinel A. Bucht H. Kunze Fraunhofer Institute for Machine Tools and Forming Technology Dresden Germany Burg Giebichenstein University of Art and Design Halle Germany

smart ³ is a cross-disciplinary network focusing on innovative and meaningful applications of smart materials. The network consists of engineers, designers and economists as well as material- and social scientists collaborating with small and medium sized enterprises. As well as giving an overview on different smart materials, this conference contribution shows how engineers and designers have cooperated in creating product concepts within the strategic categories smart production, smart mobility, smart health and smart living . Design models will visualize the output of R&D projects. The smart³-network comprises a radical change of paradigms in product development by implementing smart material functions directly into the component structure. Hence functionality will already be achieved on the material level.

关键词： smart materials design innovation management manufacturing network design method sustainable development

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Constructive methods to reduce thermal influences on the accuracy of industrial robots

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Procedia Manufacturing 2019年 33卷 19-26页

作者： Christian Mohnke Sascha Reinkober Eckart Uhlmann Fraunhofer Institute for Production Systems and Design Technology IPK Pascalstraße 8-9 10587 Berlin Germany Institute of Machine Tools and Factory Management Pascalstraße 8-9 10587 Berlin Germany

Due to their kinematics and their mobility, industrial robot systems offer a flexible, adaptable basis. An influencing variable, which is particularly relevant for processes with long process times, is the thermal heating and the associated thermal drift of the tool center point. The maximum deviation from the actual nominal position can reach up to 1.5 mm. To counteract these displacements, a cooling strategy or a targeted preheating can be installed. Both possibilities were evaluated under constructive, energetic and economic aspects and implemented on at least one axis of an industrial robot. Furthermore, a structural thermal decoupling and optimized design of the respective components were carried out. The results can help to reduce the influence of thermal heating and the associated thermal drift of the TCP by structural support without using cost-intensive measures with additional hardware and software on external computers for compensating the errors.

关键词： Robot Thermal Error Machining

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Verification of a novel measuring method for determining pre- and postoperative leg length in the context of total hip arthroplasty: a technical feasibility study

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Journal of Medical Engineering and technology 2018年第8期42卷 588-594页

作者： Schmidt, Michael Prietzel, Torsten Wendler, Toni Möbius, Robert Schleifenbaum, Stefan Hammer, Niels Grunert, Ronny ZESBO - Center for Research on Musculoskeletal Systems University of Leipzig Leipzig Germany Department of Orthopaedic Trauma and Plastic Surgery University of Leipzig Leipzig Germany Department of Orthopaedic and Trauma Surgery HELIOS Clinic Blankenhain Blankenhain Germany Department of Anatomy University of Otago Dunedin New Zealand Fraunhofer Institute for Machine Tools and Forming Technology Fraunhofer IWU Dresden Germany

Following total hip arthroplasty (THA), leg length can easily be modified, for example by different-sized endoprosthetic components. Currently, precise reconstruction depends mainly on the assessment of the surgeon. The aim of this study was to determine the accuracy of a new optical measuring system (OMS) using a novel measuring method capable of determining changes in leg length. Measurements with different investigators on an artificial leg and under clinical conditions were carried out. Measurements under clinical conditions were accomplished with a human body donor before and following prosthetic hip implantation. Furthermore, computed tomography (CT) was used to compare the function and the precision of the OMS relating to established measuring methods. The following results were achieved. The overall mean result of preoperative leg length determination by the OMS was 775.3 ± 5.8 mm (CT: 786.4 mm). The overall mean result of postoperative leg length determination by the OMS was 776.9 ± 10.8 mm (CT: 795.0mm). Measurements carried out showed that the novel measuring method works in principle. However, the viable prototype based on it has a lower accuracy compared to CT-based reference measurements, indicating the necessity of integrating more precise hardware. © 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group.

关键词： Arthroplasty

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Study on the Influence of the Processing Speed in the Generation of Complex Geometries in Aluminium Matrix Composites by Electrochemical Precision Machining

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Procedia CIRP 2018年 68卷 713-718页

作者： Norbert Lehnert Gunnar Meichsner Matthias Hackert-Oschätzchen André Martin Andreas Schubert Professorship Micromanufacturing Technology Chemnitz University of Technology 09107 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology 09126 Chemnitz Germany

Currently, an increasing demand for lightweight materials with a high strength can be observed. Potential materials, which fulfil these requirements, are particle reinforced aluminium matrix composites (AMCs). AMCs consist of an aluminium matrix, which is reinforced by ceramic particles. In a consequence, AMCs offer a strength, which is comparable to steel, along with a density, which is comparable to light metals. In the Collaborative Research Centre SFB 692 at Chemnitz University of technology, AMCs are analysed under different research aspects. One of these aspects is the generation of complex geometries by Electrochemical Precision Machining (PECM). The investigated AMC consists of ENAW 2017, which is reinforced by 10% of SiC-particles. To achieve the desired complex geometry, the dissolution characteristic of the specific AMC was analysed. Furthermore, the achievable surface quality was characterised. Based on these fundamental results, processing strategies for generating complex geometries in AMCs by PECM were derived. In this study, the influence of the PECM processing speed on the resulting complex geometry is investigated. For that purpose, a model geometry based on a retarder was selected and realized. The resulting side gap and the front gap as a function of an increasing processing voltage and an increasing feed rate are presented. It can be stated that the side gap can be reduced by an increase in feed rate.

关键词： Electro chemical machining (ECM) Metal matrix composite Aluminium Silicon carbide

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Ontology-based microservices architecture for industrial assistant systems 12

Ontology-based microservices architecture for industrial ass...

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Smart Systems Integration 2018 - 12th International Conference and Exhibition on Integration Issues of Miniaturized Systems

作者： Singer, Adrian Wenzel, Ken Müller, Jan Langer, Tino Putz, Matthias Digitalization in Production Germany Department Digitalization in Production Germany Automation and Monitoring Germany Head of Division Smart Factory - Digitalization and Automation Germany Institute Scientific Field Machine Tools Production Systems and Machining Fraunhofer Institute for Machine Tools and Forming Technology IWU Reichenhainer Straße 88 Chemnitz09126 Germany

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