doi:10.3850/978-981-07-0319-6_209

ABSTRACT

A continuous demand for metallic mass production components with progressive miniaturisation of outer dimensions and high workpiece accuracy is noticeable. Considering this development the manufacturing of these components by forming and blanking offers economical advantages as wells as a high workpiece quality. Approaching the economical and technical limits of conventional serial tool fabrication for microforming, this study presents the application of high-precision etching methods for bulk production of punches for micro blanking made of monocrystalline silicon. As the main challenge for using monocrystalline silicon as tool material is its brittleness, the purpose of the research is to study the limitations of use for micro blanking tools. Blanking experiments are performed on a high-precision, self contained machine tool, which offers the possibility of a precise punch to die alignment and punch to die clearances down to 1 µm. Besides an optimisation of the etching process for a high punch surface quality the influence of a silicon nitride coating on the tool behaviour during mechanical load is analysed. Blanking of as-rolled copper foils with a thickness of 20 µm, by using rectangular silicon punches with a width of 70 µm, shows a distinctive crack formation of coated punches while uncoated punches only have small outbreaks.

Keywords: Micro blanking, Tool production, Monocrystalline silicon, Si₃N₄ coating, Copper foil.

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