Fundamental Studies on Flexure Hinges with use in High-Precision Parallel Kinematic Micromanipulators

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The objective of the project is to comprehensively study the effects of the manufacturing process wire-cut EDM on the characteristics of flexure hinges, which are used in high precision parallel micromanipulators. This study comprises of the specific influences of the material properties, the manufacturing process, the design and the geometry on the attainable quality of positioning accuracy and life-time of the flexure hinge. Based on preliminary studies the general knowledge of the effects of the manufacturing process on the characteristics of flexure hinges will be improved by more detailed analyses as well as the consideration of additional materials and greater geometrical variety. By this generalization of the general knowledge the understanding of the manufacturing based component variation of flexure hinges can be completed. Previous investigations generally assumed ideal flexure hinges (homogenous material properties, theoretically exact geometry, no thermal effects, etc.) However during manufacturing inevitable differences occur between the actual dimensions and the specified dimensions. This affects the behavior of flexure hinges. Additionally the chosen manufacturing technology will affect the surface layer and thus influence the flexure hinge behavior especially at the smallest cross-sectional area. The impact of heat-affected-zones on the workpiece behavior increases with decreasing width of the structure. At very thin structures there is no unaffected material left and they consist entirely of heat-affected material. Thus it can be concluded: Material and manufacturing dependent peripheral rim zone characteristics affect the component behavior of filigree geometries, as found in flexure hinges in precision engineering. This effect was not at all or insufficiently analyzed in the past research of flexure hinges. The originality of this research project is the holistic approach on all aspects of flexure hinges. For a detailed research on the one hand the effect of manufacturing technology and material will be experimentally determined and on the other hand the behavior of flexure hinges for different geometries, materials and manufacturing dependent boundary conditions will be modelled theoretically. The basic effects of manufacturing technology on the flexure hinge behavior were previously studied using a reference material and predefined reference geometry. Consequently, a predictive model for the hinge behavior based on manufacturing conditions can be derived. The model of the flexure hinge behavior will be expanded to include further factors like different materials and hinge designs. The aim of this extension is to generalize the prediction model and thus to improve its usability for the end user.