Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Standardisation of Practices in Open Source Hardware
    ( 2020)
    Bonvoisin, Jérémy
    ;
    Molloy, Jenny
    ;
    Häuer, Martin
    ;
    Wenzel, Tobias
    Standardisation is an important component in the maturation of any field of technology. It contributes to the formation of a recognisable identity and enables interactions with a wider community. This article reviews past and current standardisation initiatives in the field of Open Source Hardware (OSH). While early initiatives focused on aspects such as licencing, intellectual property and documentation formats, recent efforts extend to ways for users to exercise their rights under open licences and to keep OSH projects discoverable and accessible online. We specifically introduce two standards that are currently being released and are seeking early users and contributors, the DIN SPEC 3105 and the Open Know-How Manifest Specification. Building on this, we reflect on challenges around standardisation in the OSH community and on relevant areas for future development such as an open tool chains, modularity and hardware-specific interface standards.
  • Publication
    Automated Tool-Path Generation for Rapid Manufacturing of Additive Manufacturing Directed Energy Deposition Geometries
    ( 2020)
    Biegler, Max
    ;
    Wang, Jiahan
    ;
    Kaiser, Lukas
    ;
    Rethmeier, Michael
    In additive manufacturing (AM) directed energy deposition (DED), parts are built by welding layers of powder or wire feedstock onto a substrate with applications for steel powders in the fields of forging tools, spare parts, and structural components for various industries. For large and bulky parts, the choice of tool-paths influences the build rate, the mechanical performance, and the distortions in a highly geometry-dependent manner. With weld-path lengths in the range of hundreds of meters, a reliable, automated tool-path generation is essential for the usability of DED processes. This contribution presents automated tool-path generation approaches and discusses the results for arbitrary geometries. So-called “zig-zag” and “contour-parallel” processing strategies are investigated and the tool-paths are automatically formatted into machine-readable g-code for experimental validation to build sample geometries. The results are discussed in regard to volume-fill, microstructure, and porosity in dependence of the path planning according to photographs and metallographic cross-sections.
  • Publication
    A practical approach to reduce energy consumption in a serial production environment by shutting down subsystems of a machine tool
    ( 2019)
    Can, Alperen
    ;
    Thiele, Gregor
    ;
    Krüger, Jörg
    ;
    Fisch, J.
    ;
    Klemm, C.
    Energy efficiency in production is becoming increasingly important for the automotive industry, motivated by political regulations and competitiveness. Many theoretical approaches to achieve an efficient production via advanced control have only been tested in experimental environments. Important for the transfer into serial production is the proof that all requirements (e.g. quantity and quality) will be met. For ensuring production on demand, machine tools (MT) imitate the real production process to keep themselves at operating temperature. All subsystems of a MT operate at full power in this state, disregarding its necessity. Shutting down these subsystems during non-productive periods is a promising approach for saving energy. This paper will present a method for shutting down components during non-productive periods, while ensuring the ability to produce on demand. Successful tests were already performed during live operation in a plant of a car manufacturer in Berlin, Germany.
  • Publication
    Framework for energy efficiency optimization of industrial systems based on the Control Layer Model
    ( 2019)
    Thiele, Gregor
    ;
    Heimann, Oliver
    ;
    Grabowski, Knut
    ;
    Küger, Jörg
    In the context of sustainable manufacturing, the energy efficient operation of industrial systems is of major interest. This paper presents a modular framework for practical research about energy efficiency optimization of complex technical systems. Whereas many approaches focus on stand-alone machines or processes, this approach is concerned with energy-related coupling of several entities. Using a method for energy-related key performance indicators, the overall efficiency is deduced from all subsystems. A given topology is modeled in an XML-based format, inspired by AutomationML. The framework gives the opportunity to analyze and compare optimization algorithms. First experiments with two optimization algorithms were applied to a simulated cooling system.
  • Publication
    Influence of heat input and preheating on the cooling rate, microstructure and mechanical properties at the hybrid laser-arc welding of API 5L X80 steel
    ( 2018)
    Turichin, G.
    ;
    Kuznetsov, M.
    ;
    Pozdnyakov, A.
    ;
    Gook, S.
    ;
    Gumenyuk, A.
    ;
    Rethmeier, M.
    This study investigates the influence of hybrid laser-arc welding parameters: heat input and preheating on the cooling rates, microstructure and mechanical properties of the welding joint. Samples from API 5L X80 steel with root thickness 14 mm were welded using welding wire MF 940 M. Decreasing cooling rate of welds from 588 °C/sec up to 152 °C/sec, weld metal hardness from 343±12 HV up to 276±6 HV and ultimate tensile strength from 1019.5±14 MPa up to 828±10 MPa and increasing bainite phase term of the weld metal was detected at the increasing preheating temperature up to 180 °C and maximal heat input. The mathematical relations of the input and output parameters were created using linear regression equations. Preheating temperature 180 °C allows increasing maximal welding speed up to more than 3.0 m/min with acceptable welding joint quality.
  • Publication
    Sustainable Innovation in a Multi-University Master Course
    ( 2018)
    Gladysz, Bartlomiej
    ;
    Urgo, Marcello
    ;
    Gaspari, Lorenzo
    ;
    Pozzan, Giovanna
    ;
    Stock, Tim
    ;
    Haskins, Cecilia
    ;
    Jarzebowska, Elzbieta
    ;
    Kohl, Holger
    Mobility, multi-locality, and transnational migration are current social developments among the population of the European Union. These social developments in society and companies, linked to the challenges of sustainability, lead to new requirements for working in the European Union. Teaching and learning in higher education needs to adapt to these requirements. As a result, new and innovative teaching and learning practices in higher education should provide competencies for transnational teamwork in the curriculum of tomorrow's engineers in order to ensure their competitiveness in the job market and advantage in their future careers. Thirteen European students from four countries participated in a new project-based course, called the ""European Engineering Team"". Students focused on the development of two innovative and sustainable products. The goal of this paper is to present the thermal pallet cover, which is the result of the first one-year transnational and sustainability-oriented project. This paper also aims to present the process of performing the project. It provides the overview and discussion of engineering and management tasks that students completed in the transnational environment, working remotely at their own campuses between scheduled transnational meetings. The work contributes to project-oriented learning that may constitute a basis for teaching holistic engineering courses at mechanical and industrial engineering departments.
  • Publication
    Human robot collaboration - using kinect v2 for ISO/TS 15066 speed and separation monitoring
    ( 2018)
    Rosenstrauch, Martin J.
    ;
    Pannen, Tessa J.
    ;
    Krüger, Jörg
    The use of industrial robots within assembly workstations where human and robot should be able to collaborate or even cooperate involve high safety requirements. One out of four possibilities outlined in the current technical specification ISO/TS 15066 for ensuring safety is speed and separation monitoring. Here the robot motion speed in- or decreases dynamically depending on the distance between operator and robot. This paper introduces an approach of a speed and separation monitoring system with the help of a time of flight sensing. After introducing this safety ensuring method, a Microsoft Kinect V2 is used to continuously detect human worker within a shared workspace. With the help of the robots joint angles from the robot control it is possible to compute the distances between all robot joints and the human worker. The shortest distance, which is at the same the critical distance time, is determined and as a consequence the velocity and acceleration values of the robot were set to safe values according to ISO/TS 15066. As it is not necessary to visually detect also the robot, but only human workers, this approach is very resilient. Afterwards the introduced setup is tested by a real detected human in front of a Kinect and a simulated industrial robot (Universal Robot UR5) in the robot operating system ROS. Measurements show that depending on the position of the worker the robots speed adapts to recommended safety values up to a complete halt if necessary. Conclusively all results are discussed and an outlook for possible fields of applications is given.
  • Publication
    Assessing the predictive capability of numerical additive manufacturing simulations via in-situ distortion measurements on a LMD component during build-up
    ( 2018)
    Biegler, Max
    ;
    Graf, Benjamin
    ;
    Rethmeier, Michael
    Due to rapid, localized heating and cooling, distortions accumulate in additive manufactured laser metal deposition (LMD) components, leading to a loss of dimensional accuracy or even cracking. Numerical welding simulations allow the prediction of these deviations and their optimization before conducting experiments. To assess the viability of the simulation tool for the use in a predictive manner, comprehensive validations with experimental results on the newly-built part need to be conducted. In this contribution, a predictive, mechanical simulation of a thin-walled, curved LMD geometry is shown for a 30-layer sample of 1.4404 stainless steel. The part distortions are determined experimentally via an in-situ digital image correlation measurement using the GOM Aramis system and compared with the simulation results. With this benchmark, the performance of a numerical welding simulation in additive manufacturing is discussed in terms of result accuracy and usability.
  • Publication
    Embedding electronics into additive manufactured components using laser metal deposition and selective laser melting
    ( 2018)
    Petrat, Torsten
    ;
    Kersting, Robert
    ;
    Graf, Benjamin
    ;
    Rethmeier, Michael
    The paper deals with the integration of a light emitting diode (LED) into an additive manufactured metal component. Selective laser melting (SLM) and laser metal deposition (LMD) are used. The material used is the chrome-nickel steel 316L. The basic component is manufactured by means of SLM and consists of a solid body and an area with grid structure. The solid body includes a duct in the shape of a groove with a recess for the positioning of the power cable. The LED is embedded in the grid structure via an inlet from the solid body. In further processing, the groove is filled with LMD. Two strategies with different parameter combinations were investigated. It shows that a high energy input near the power cable leads to its destruction. By using multiple parameter combinations during the manufacturing process, this destruction can be prevented. There was a comparison of both strategies with regard to the necessary number of tracks and duration of welding time.
  • Publication
    Perspectives for International Engineering Education
    ( 2018)
    Stock, Tim
    ;
    Kohl, Holger
    A global transformation from an economic towards a sustainable development is promoted by current policies from the United Nations and the European Union. Young engineers must be trained to anticipate the sustainability challenges for contributing bottom-up to a global sustainable development. Besides, they must be capable of performing in a more and more dynamic, transnational, and intercultural global working environment. Consequently, new perspectives for teaching and learning in higher engineering education are required, providing the competencies for coping with the sustainability challenges and for working within the dynamic global society. A transnational and project-oriented teaching and learning framework is outlined, which provides the future key competencies for young engineers. Based on this framework, the inter-university master course ""European Engineering Team"" is presented. The master course fosters the development of sustainable and entrepreneurial initiatives by leading the students through the development phases of a start-up company grounding on a sustainable innovation. A first evaluation of the master course shows, that most of the students' key competencies have been improved significantly.