Fraunhofer-Institut für Produktionsanlagen und Konstruktionstechnik IPK

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  • Publication
    Development of a material model for visco-elastic abrasive medium in abrasive flow machining
    ( 2013)
    Uhlmann, Eckart
    ;
    Doits, M.
    ;
    Schmiedel, Christian
    Abrasive Flow Machining (AFM) uses the visco-elastic properties of a polymeric carrier, combined with abrasive grains, as a tool for machining of difficult to reach geometries, such as holes or cavities. Due to the design of the workpiece holding device and variable flow rates, the complex shear modulus of the polymer can locally be influenced and thus a targeted removal on the workpiece can be produced. As a result there is a reproducible material removal, causing requested polishing, deburring or edge rounding. Due to shear thinning and visco-elastic behavior of the tool, the process simulation for AFM is very complex and has not been implemented yet including an exact physical material model. Initial machining parameters so far are based on experience and extensive experiment al research. This publication gives an insight into the investigation of modeling the abrasive media in AFM by adapting the standard Maxwell model of elastomers and extending it to the Generalized Maxwell model. Assuming the material removal of the process being caused by the shear stressed dependent bonding of the abrasive grains, a fundamental material model, easy to be integrated in conventional simulation programs, is developed and presented in this paper.
  • Publication
    Simulation of product development processes
    ( 1998)
    Krause, F.-L.
    ;
    Raupach, C.
    In order to achieve fast and efficient product development a lot of supporting tools have been developed in recent years. Tools to support collaborative work and virtual prototyping can be used optimally only if the underlying processes are restructured according to the functionality of the tools. Therefore the planning of product development processes considering the possibilities of the CA-systems becomes crucial for manufacturing industries. However, there are only a few systems to support the planning and validation of future product development processes. This paper describes a simulation system for a process oriented analysis of existing and planned product development processes. These processes have certain characteristics not to be found in other business processes, e.g. iterative loops, data and information management as well as uncertainty about the precise conduction of the processes. Taking these aspects into account the presented simulation system supports improvement effo rts and reengineering by analysing the existing processes and verifying planned processes both in early stages using a rough description and in later stages using a detailed product development process plan.
  • Publication
    Simulation als Grundlage der Bewertung und Optimierung von Produktentwicklungsprozessen
    ( 1995)
    Krause, F.-L.
    ;
    Loske, B.
    ;
    Golm, F.
    ;
    Raupach, C.
    Dringende Investitionsentscheidungen zur Stärkung der Wettbewerbsfähigkeit werden im Produktentwicklungsbereich nur schleppend getroffen, weil keine geeigneten Methoden zur Analyse und Bewertung neuer Entwicklungsstrategien und entsprechender informationtechnischer Konzepte im Produktentwicklungsprozeß zur Verfügung stehen. Simulationstechnik als Analysewerkzeug komplexen dynamischer Systeme in Verbindung mit einem Planungssysten zur Bewertung und Optimierung von Ablaufstrukturen wird als ein effizientes Planungskonzept für das Reengineering von Produktentwicklungsprozessen vorgestellt.
  • Publication
    Factory planning using integrated information and material flow simulation
    ( 1994)
    Mertins, K.
    ;
    Rabe, M.
    ;
    Jochem, R.
    Planning and optimization of factories is a complex task. Information flow and material flow have to be studied in an integrative way in order to achieve highest quality standards of planning results. With the help of computer aided methods the authors suggest planning support by an enterprise specific reference model for the development of an information flow concept and by a material flow model for the development of a logistics concept. As information and material flow will influence each other very intensively, these models should base on a common kernel, which is described with the same modelling approach. The authors propose an Integrated Enterprise Modelling (IEM) method, which uses the object oriented modelling approach. Main features are the close relation between functions and data of an object (encapsulation), inheritance, and the class concept. With MO2GO (based on IEM) and MOSYS, IPK Berlin has developed two planning systems which justly fit the need of todays industrial p lanning requirements.
  • Publication
    The realistic robot simulation -RRS- interface
    ( 1994)
    Bernhardt, R.
    ;
    Schreck, G.
    ;
    Willnow, C.
    Tools for simulation and off-line programming became an important means for economic application of industrial robots. Until now the accuracy of simulation was not sufficiently precise for reliable down-load and execution of the off-line generated programs. A main cause for this was the controller specific motion behaviour of the robots that could not be simulated with sufficient accuracy. The RRS-project was created to overcome this deficite. By defining a suitable interface, it was made possible to integrate original controller software for motion behaviour into off-line programming systems.
  • Publication
    Development demands for robotized manufacturing systems
    ( 1993)
    Bernhardt, R.
    ;
    Schreck, G.
    Software tools for planning and simulations of robotized systems are commercially available and more and more used in industry. The intention of using these tools is to support the whole procedure form the selection of the robots and workcell components, the generation of all task programs down to the execution of the manufacturing task in the real workcell at the shopfloor. Additionally methods and tools concerning measurements, calibration, monitoring and diagnosis have to be considered. Today not all of the necessary steps for planning, implementing, operating and maintaining robotized manufacturing systems are adequately considered. In this article the principle demands for future developments are stated. Furthermore the R and D work which has been performed in this connection by the European Strategic Programme for Research and Development in Information Technology (ESPRIT), will be described on the basis of a few selected projects.
  • Publication
    Hierarchical modelling of production systems
    ( 1992)
    Bergmann, M.
    ;
    Mertins, K.
    ;
    Rabe, M.
    Modern simulation systems enable modelling of large an production systems. To achieve an adequate model struc hierarchical modelling is absolutely necessary. These to be available for all model elements, describing mac layout. The authors have developed a method of hierarc for system structure, process plans and product input. hierarchical model can be simulated, from a single lea up to the complete model. Within the corresponding too check and binding across the hierarchical levels are e automatically. In case of contradictions, rules decide appropriate informations taken from the submodels. across the hierarchical levels are executed automatically. In case of contradictions, rules decide about the appropriate informations taken from the submodels.
  • Publication
    Software system for simulation and control synthesis of robots for metal machining processes
    ( 1991)
    Stokic, D.
    ;
    Vukobratic, M.
    ;
    Surdilovic, D.
    The software system for simulation and synthesis of control of manipulation robots which are intented for metal machining is presented in the paper. The package includes various dynamic models of a robot in the contact with a constraint surface. These models are considered and the problems of application of these models are compared in the paper from standpoints of both computer simulation and their application within position/force control schemes. Numerical examples of these comparisons are given. The package also includes models of some specific robotic tasks.
  • Publication
    An adaptive hybrid control scheme for manipulation robots with implicit force control
    ( 1991)
    Stokic, D.
    ;
    Vukobratic, M.
    ;
    Surdilovic, D.
    An adaptive hybrid position/force control scheme for manipulation robots in constrained motion tasks is considered in the paper. The proposed control scheme is based at implicit force control, although it includes explict force feedback loop, too. The scheme includes the block for identifaction of contact force parameters, as well block for tuning of feedback gains according to the identified parameters. The scheme is briefly described and the simulation tests are presented.