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High‐Speed Roll‐to‐Roll Hot Embossing of Micrometer and Sub Micrometer Structures Using Seamless Direct Laser Interference Patterning Treated Sleeves
Author(s) -
Rank Andreas,
Lang Valentin,
Lasagni Andrés Fabián
Publication year - 2017
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.201700201
Subject(s) - homogeneity (statistics) , materials science , laser , micrometer , mold , embossing , composite material , roll to roll processing , optics , computer science , physics , machine learning
In this study, we present a seamless high‐speed roll‐to‐roll hot embossing process using a direct laser interference patterned nickel sleeve as a mold. Line‐like patterns with spatial periods of 5.0, 3.9, and 1.5 μm and structure heights of 572, 325, and 141 nm, respectively are used for imprinting PET‐foils. The influence of the web speed on the cavity filling and consequently on the structure height and homogeneity of the fabricated patterns is studied. The web speed is varied between 2 and 50 m min −1 . For the 5.0 and 3.9 μm periods, a decrease in structure height with the web speed occurs, while for the 1.5 μm period the structure height remains constant in the tested interval. Also a decrease in homogeneity is observed with increasing web speed. Finally, an analytical model, based on the Navier–Stokes equation and Hertzian contact pressure, is used to explain the experimental results. The experimental data are in good agreement with the calculated theoretical values.