Details

Autor(en) / Beteiligte

• Schell, Torsten

Titel

Grundlegende Untersuchungen Einer Neuen Rapid Tooling Technik für Die Blechumformung

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

2005

Link zum Volltext

• ProQuest

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• Generative methods are becoming more and more predominant in the product manufacturing process for safeguarding both concept and construction. The advantage of Rapid Prototyping, which allows automated and fast production of any kind of complex geometries directly on the basis of CAD data sets, has not yet been used for producing metal sheet prototypes. By further developing the LOM method this gap is now being closed. A basic prerequisite for this step is to improve the mechanical properties of the LOM tools. The development of a novel paper material and its infiltration with epoxy resins provide the basis for producing metal forming tools using Rapid Prototyping technology. To provide a novel paper material and modified thermal plastic glue the manufacturing parameters of the LOM system have to be tested. The quality of the LOM components after infiltration with epoxy resin during an additional process step depends directly on the manufacturing parameters of the green parts. These two demands on the setup of the system - production of the LOM component and infiltration - are competing with each other. Suitable manufacturing parameters can be determined for each of the two production steps. The hardening process is described using a mathematical model of the reaction kinetics of the used resin system. This model allows predicting the behaviour of the resin system within the kinetically defined range. Via numerical calculation of the hardening process the optimal annealing cycle can be simulated and applied on practical usage. Using the calculated ideal temperature progression of the hardening process, the cycle time can be reduced significantly as compared to conventional hardening procedures. LOMip is a novel material system whose sheet metal forming properties are not yet understood. The sandwich structure composed of individual sheets of papers results in an anisotropic material behaviour of LOMip which is similar to that of fibre-reinforced plastics. The mechanical parameters are determined by using tensile, pressure and bending tests executed on differently oriented LOMip specimens. To describe the material's behaviour under load an appropriate, simplified material model is created. The characteristic sandwich structure of the LOMip tools yields a tribological behaviour that is dependent on the design. By employing a simplified mechanical and tribological material model the simulation of the metal forming process is realized utilizing a volume-networked tool model. With the help of this modelling the effect of tool resilience on the metal forming component can be simulated. The simulations performed on the individual tool models illustrate, however, that the influence of the anisotropic tool behaviour on component geometry can be neglected. A practice-oriented application test is performed for different sheet metal components and manufacturing procedures. The feasible small-batch production of aluminium structure components for the aviation industry shows the potential of the LOMip manufacturing technology for sheet metal forming. The limits in manufacturing aluminium sheet metal components are within the range of visual components. The sandwich construction of the tool and the resulting surface structure do not allow manufacturing of components with a Class-A surface. The production of steel metal components with a sheet quality of up to H320LA and a thickness of 2.2 mm presents the maximum result that is obtained by LOMip tools in sheet metal forming. The sheet metal forming behaviour can also be studied in the "Napfchen" test, which proves - as already predicted by simulation - that the behaviour does not depend on the orientation of the bars. In addition to the technical suitability for deep drawing, the examined LOMip manufacturing procedure also has to meet the economical requirements of prototype manufacturing. The QFD method serves as the basis on which the LOMip procedure can be compared with other manufacturing procedures. A direct comparison with other tooling procedures demonstrates the advantages of the LOMip process over these procedures especially in the field of small and complex tools. The simple data preparation and fully automated production also contribute to the gained cost and time advantage.