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Microstructuring by a combination of micro impact extrusion and shear displacement forming

Mikrostrukturierung mittels einer Kombination von Mikrofliesspressen und Durchsetzen
: Schubert, Andreas; Jahn, Stephan; Müller, Benedikt


Alves de Sousa, Ricardo ; European Scientific Association for Material Forming:
The Current State-of-the-Art on Material Forming : Selected, peer reviewed papers from the 16th ESAFORM Conference on Material Forming, April 22-24, 2013, Aveiro, Portugal
Dürnten: Trans Tech Publications, 2013 (Key engineering materials 554-557)
ISBN: 978-3-03785-719-9 (Print)
ISBN: 978-3-03795-469-0 (CD-ROM)
ISBN: 978-3-03826-100-1 (eBook)
International Conference on Material Forming (ESAFORM) <16, 2013, Aveiro>
Conference Paper
Fraunhofer IWU ()
microforming; micromanufacturing; impact extrusion; shear displacement; hybrid forming

The Collaborative Research Centre SFB/TR 39 PT-PIESA is developing mass production technologies and process chains for the fabrication of aluminium piezo composites, which can be used as raw material for "smart sheet metal" [1]. Microstructuring by forming is a challenging task concerning material flow, tool and process design [2]. In this study, a hybrid forming process combined of micro impact extrusion and shear displacement is presented and discussed. The formed microstructure consists of ten parallel primary cavities with cross sections of 0.3\'020.3 mm2 and four larger secondarycavities which are surrounding the primary cavities. High demands are made concerning precision and reproducibility of the cavities' geometry according to the function of the cavities, which is to serve as collets for sensitive piezo rods. The microstructure has to be formed with one stroke of the stamp. Micro backward impact extrusion is chosen for structuring the primary cavities since it allows accurate forming without aligning die plate and stamp due to a flat die plate. Shear displacement forming, which is the selected process for the secondary cavities, requires a structured and aligned die plate but the forming forces are significantly lower than forming the same geometry with an extrusion process, which in turn increases the accuracy. The investigations are focused on the characterization of samples formed with the hybrid process in comparison to structures which are formed solely by impact extrusion. Geometric parameters, material flow and process parameters were evaluated to assess the hybrid process. First experiments show promising results, whereas higher degrees of deformation could be reached at lower forming forces.