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Modeling approach regarding surface functionalization by force-controlled micro and nano forming

 
: Uhlmann, E.; Kühne, S.; Jagodzinski, M.; Malcher, M.; Trevino, R.

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European Society for Precision Engineering and Nanotechnology -EUSPEN-:
17th International Conference & Exhibition of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2017 : 29th May – 2nd June 2017, Hannover, Germany
Bedford: Euspen, 2017
ISBN: 978-0-9957751-0-7
S.211-212
European Society for Precision Engineering and Nanotechnology (EUSPEN International Conference & Exhibition) <17, 2017, Hannover>
Englisch
Konferenzbeitrag, Elektronische Publikation
Fraunhofer IPK ()

Abstract
Surface functionalization allows the control of fluidic, tribological, biological or optical properties. Suitable processes are interference lithography (IL), ultra-precision machining and micro and nano forming. The force-controlled forming process enables a reproducible production of structures with an absolute height in the double-digit nanometer range. The deformation is a complex process consisting of controlled and uncontrolled material deposition. Knowledge about the uncontrolled behaviour, however, allows a reproducible production of defined structures. A model approach with regard to machining parameter prediction is presented here. The tool shape is transferred into the surface by plastic penetration of a faceted diamond tool. By means of a superimposed tool movement, linear structures can be generated. Surface functionalization allows the control of fluidic, tribological, biological or optical properties. Suitable processes are interference lithography (IL), ultra-precision machining and micro and nano forming. The force-controlled forming process enables a reproducible production of structures with an absolute height in the double-digit nanometer range. The deformation is a complex process consisting of controlled and uncontrolled material deposition. Knowledge about the uncontrolled behaviour, however, allows a reproducible production of defined structures. A model approach with regard to machining parameter prediction is presented here. The tool shape is transferred into the surface by plastic penetration of a faceted diamond tool. By means of a superimposed tool movement, linear structures can be generated. Larger areas can be structured by repeating this process. The advantage of the force control in comparison to the displacement control is a defined penetration depth relative to the surface with reproducibility in the single-digit nanometer range. The force-control is carried out gravimetrically (0.05 N < F < 0.15 N). Therefore the tool and additional precision weights are suspended on low stiffness (C = 0.0007 N/μm) flexures. The structuring of free formed surfaces can be realized by adapted tool manipulation. For this purpose, the tool needs to be guided along the corresponding surface. Depending on the structure, suspension of the tool can tolerate shape deviations of the substrate. This process can be adapted to different materials and applications. The development of the model is based on the example of diffractive optical structures (1000 mm-1 < g < 500 mm-1, 30 nm < h < 300 nm) and statistical experimentation. The deviation of the ideal profile from the cross-sectional area measured via AFM was used as control variable. A surface deviation that approaches nearly zero (10 nm² < Aneg < 100 nm²) is considered as ideal load. As additional result of these experiments, physical approaches are available, which can later form the basis of a physical model.

: http://publica.fraunhofer.de/dokumente/N-502885.html