doi:10.3850/978-981-07-0319-6_210

ABSTRACT

Micro structures may add functionalities to the surface of a plastics part and may enable a completely new set of applications. Examples are unwettable surfaces known from the lotus leaf or anti-reflex surfaces for display applications also known as the moth eye effect. It has been shown that injection moulding with variothermal process control is a suitable process for the fabrication of plastics parts with micro-structured surfaces. However, technologies for the fabrication of these micro-structured functional surfaces are still limited to flat and even shaped part geometries. To use the effect of functional micro-structured surfaces on complex parts, a technology for the manufacturing of these surfaces on 3D-shaped parts is required. For this purpose, the fabrication of cone-shaped structures with sizes of 30 µm on plastics parts with 3D geometry is being investigated. An injection mould with an integrated laser-based cavity heating system is adapted to heat 3D-shaped surfaces. In a first step, the temperature profile on the cavity surface is being analysed by thermography. After a first series of moulding trials with a polypropylene material, the moulding of the structures on the surface of a part with the shape of a ball scraper is evaluated by scanning electron microscopy. It is shown, that a precise and uniform moulding of microstructures on complex part geometries can be achieved under sufficient process conditions.

Keywords: Micro structures, Injection moulding, Variothermal process control.

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