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Kongens Lyngby, Denmark

Rebeggiani S.,Halmstad University | Dimkovski Z.,Halmstad University | Kofod G.,InMold Biosystems | Rosen B.-G.,Halmstad University
Tribologia | Year: 2014

Dies and moulds with high precision surfaces are being used in various branches, e.g. in the plastic industry where the surface finish are conventionally performed by manual polishers. With ever increasing demands of shorter lead times and reduced costs, efforts have been made to automate this finishing process. This paper presents an empirical study performed to test durability properties of SOG (spin-on-glass)-layers on steel surfaces. The results showed that the thin coating last longer than the thicker ones, and that the harder coatings withstood wear significantly better than the steel reference samples thus motivating further investigations.

Mohaghegh K.,Technical University of Denmark | Hansen H.N.,Technical University of Denmark | Pranov H.,InMold Biosystems | Kofod G.,InMold Biosystems
Proceedings of the 13th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2013 | Year: 2013

Thin film coatings are extremely interesting for industries, where there is a need to protect a highly accurate surface which has tight dimensional tolerances. The topic is important both in the production of new metallic tools and repair applications. In both applications it is vital to have a specific knowledge about coating thickness and roughness. In the present paper a novel application of a transparent HSQ coating is presented. Furthermore the thickness and roughness of the transparent coating with nominal thickness of 1 μm is measured in the presence of surface roughness of the substrate. Measurements were done using AFM and a precision 3D mechanical stylus instrument.

Mohaghegh K.,Technical University of Denmark | Hansen H.N.,Technical University of Denmark | Pranov H.,InMold Biosystems | Kofod G.,InMold Biosystems
Conference Proceedings - 14th International Conference of the European Society for Precision Engineering and Nanotechnology, EUSPEN 2014 | Year: 2014

The paper discusses a novel application of a thin layer coating on a metallic machined surface with particular attention to roughness of the coating compared to the original surface before coating. The coating is a nominally 1 μm film of Hydrogen Silsesquioxane (HSQ) which is commonly used in the semiconductor industry in the manufacture of integrated circuits. The work piece is a fine peripheral-milled tool steel surface which is widely used in industrial applications. Roughness improvement after the application of HSQ coating is reported.

Cech J.,Technical University of Denmark | Pranov H.,InMold Biosystems | Kofod G.,InMold Biosystems | Matschuk M.,InMold Biosystems | And 2 more authors.
Technical Proceedings of the 2013 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2013 | Year: 2013

Nanostructured surfaces offer advanced functionality, such as stunning structural colors, antireflective, self-cleaning or antifogging effect. Polymer injection molding provides a cost effective method to fabricate plastic objects with complex shapes and is known to replicate nanosized details of the mold surface. It is however difficult to pattern the mold, in particular if non-planar surface is needed. We show a novel method using nanopatterned nickel foils for a room temperature nanoimprinting into hydrogen silsesquioxane (HSQ) spray-coated films deposited on freeform surfaces. Due to the high viscosity of HSQ, pressures up to 800 bar need to be used. We have been able to imprint the 426 ran period nanopattern onto conical and spherical substrates with a radius of curvature as low as 500 urn, using a specially developed high pressure hydrostatic imprinting device. Pattern distortions, resulting from a contact between the intrinsically planar foil and double-curved substrate have been found and measured as a function of a radial distance to the apex of spherical protrusion. This way, a feasible method to create freeform molds with nanopatterned surface is demonstrated. This facilitates new options for production of affordable polymer articles with novel surface functionalities.

Hobaek T.C.,Technical University of Denmark | Matschuk M.,InMold Biosystems | Kafka J.,InMold Biosystems | Pranov H.J.,InMold Biosystems | Larsen N.B.,Technical University of Denmark
Journal of Micromechanics and Microengineering | Year: 2015

We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process. At isothermal mold conditions, the average pillar height increases by up to 100% and a more uniform height distribution is observed compared to a traditional metal mold insert. Thermal heat transfer simulations predict that the HSQ film retards the cooling of the polymer melt during the initial stages of replication, thus allowing more time to fill the nanoscale cavities compared to standard metal molds. A monolayer of a fluorinated silane (heptadecafluorotrichlorosilane) deposited on the mold surface reduces the mold/polymer interfacial energy to support demolding of the polymer replica. The mechanical stability of thermally cured HSQ makes it a promising material for nanopattern replication on an industrial scale without the need for slow and energy intensive variotherm processes. © 2015 IOP Publishing Ltd.

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