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Procedure and Validation of the Implementation of Automated Sensor Integration Kinematics in an LPBF System

Procedia CIRP 2020年 93卷 1304-1309页

作者： Maximilian Binder Christian Dirnhofer Philipp Kindermann Max Horn Matthias Schmitt Christine Anstaett Georg Schlick Christian Seidel Gunther Reinhart Fraunhofer IGCV (Research Institution for Casting Composite and Processing Technology) Beim Glaspalast 5 86153 Augsburg Germany Department of Applied Sciences and Mechatronics University of Applied Sciences Munich Lothstr. 34 80335 Munich Germany Technical University of Munich Institute for Machine Tools and Industrial Management Boltzmannstr. 1585748 Garching Germany

The in-situ integration of sensors into additive manufactured (AM) components is becoming increasingly important and moving into the focus of current research. However, manual sensor integration during the metal- and laser-based powder bed fusion (LPBF) process is usually associated with long process downtimes, the loss of the shielding gas atmosphere and a change in component temperature. The resulting effects are e.g. changed mechanical properties. Therefore, one way to avoid these effects is presented by automated sensor integration. A procedure for the design of kinematics to meet the requirements is presented and experimentally validated. As a result, a functional automation unit in an LPBF plant is presented.

关键词： automated sensor integration metal additive manufacturing smart parts laser based powder bed fusion laser beam melting multi-material

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Smart components by additive technologies

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IOP Conference Series: Materials Science and Engineering 2019年第1期480卷

作者： I Dani Fraunhofer Institute for Machine Tools and Forming Technology Germany

Smart components are key technologies for industry 4.0 as well as the Internet of Things. The application areas include e.g. systems for sustainable production, automotive, smart agriculture, and smart home. In order to integrate intelligence within a component, a sensor or actuator system typically needs to be embedded within the component itself during fabrication. Additive manufacturing has been extended to more and more industries and is now being used not only in toolmaking, but also in the series production of components. Geometric functionalization for conformal cooling is already state of the art in tool making. Despite the great potential of function-integrated parts, publications on sensor integration into parts fabricated by additive manufacturing are still rarely found. First approaches address multimaterial printing by using insulating and conductive materials as well as the integration of smart elements during the printing process. Laser beam melting (LBM) is an additive manufacturing technology for geometrically complex parts based on the layer wise and selective melting of metal powders. As proof-of-concept of the developed integration concept, based on LBM, the functionalization of tools and medical implants will be presented.

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Influence of pass reduction in cold rolling on damage evolution in deep drawing of rotationally symmetric cups

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

作者： M Nick C Liebsch M Müller IF Weiser G Hirt T Bergs Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen University Campus-Boulevard 30 52074 Aachen Germany Institute of Metal Forming (IBF) of RWTH Aachen University Intzestr. 10 52072 Aachen Germany Fraunhofer Institute for Production Technology IPT Steinbachstr. 17 52074 Aachen Germany

Improvement of component performance by controlling the damage state after metal forming enables a reduction in sheet thickness and, consequently, in component weight and material cost. To establish methods for controlling damage in finished parts, the entire process chain from steelmaking and casting through hot and cold rolling to deep drawing must be considered. Previous research has shown that in hot rolling of an S355 steel, the influence of pass reduction on damage in the hot strip disappears when the accumulated pass reduction becomes large. However, the influence of cold rolling parameters on damage and specifically on its evolution in subsequent forming processes has not yet been systematically investigated. In the present work, specimens of the the mentioned S355 steel are cold rolled with two different pass reductions and heat treated to obtain a DP800 dual phase steel. These specimens are deep drawn into rotationally symmetric cups with variation of the drawing die radius. Sheet specimens and deep drawn cups are investigated using scanning electron microscopy to determine the respective void area fractions. While no influence of height reduction on the void area fraction after cold rolling is found, the void area fraction after deep drawing differs with variation of the pass reduction. This effect is connected to the formation of a larger number of small voids in the material rolled with a larger pass reduction.

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Modified Cross-Wedge Rolling for Creating Hollow Shafts

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Procedia Manufacturing 2018年 21卷 53-59页

作者： Dirk Landgrebe Jürgen Steger Uwe Böhmichen Markus Bergmann Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Reichenhainer Str. 88 09126 Chemnitz Germany

Cross-wedge rolling (CWR) is an incremental forming method for producing rotationally symmetric components such as a basic shape of gear shaft or a preform before impression die forging. In CWR the material of a solid cylindrical billet is redistributed in axial direction while the billet diameter is reduced. Conventional CWR cannot be used to produce hollow shapes. This paper presents a modified CWR process, which enables the manufacturing of hollow shafts and thus provides a technological base for utilizing the large potential of the method regarding cost and resource efficiency in mass production. The method introduces two mandrels which act concurrently with the tooling wedges in an elaborate kinematic system. During processing, the generated shear stresses induce fracturing located along the billet axis. The actively driven mandrels use the fracture and penetrate axially into the workpiece. This paper provides a description of the basic principle of this innovative method and discusses the complex interaction between tool geometries, kinematic system and processing parameters.

关键词： Production Process Hot Forging Cross-wedge Rolling Tubing Billet Preforming

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Constructive compensation of the thermal behaviour for industrial robots

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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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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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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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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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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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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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