A new two-step method, facilitating the rapid generation of super-hydrophobic surface structures via parallel laser processing followed by a replica generation by injection molding is reported. A self-made fused silica-based diffractive optical element (DOE) is applied to distribute the laser energy into a 25 × 25 dot matrix. This DOE is used as a transmission mask for surface ablation of metal molds, applying short-pulse UV laser pulses. In a subsequent process step, replicas of the processed stamp are produced by variothermal injection molding, enabling the mass production of the surface pattern on plastics parts. The resulting topography facilitates a super-hydrophobic behavior of the fabricated components.

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Molding of micro structures by injection molding leads to special requirements for the molds e.g. regarding wear resistance and low release forces of the molded components. At the same time it is not allowed to affect the replication precision. Physical vapor deposition (PVD) is one of the promising technologies for applying coatings with adapted properties like high hardness, low roughness, low Young's modulus and less adhesion to the melt of polymers. Physical vapor deposition technology allows the deposition of thin films on micro structures. Therefore, the influence of these PVD layers on the contour accuracy of the replicated micro structures has to be investigated. For this purpose injection mold inserts were laser structured with micro structures of different sizes and afterwards coated with two different coatings, which were deposited by a magnetron sputter ion plating PVD technology. After deposition, the coatings were analyzed by techniques regarding hardness, Young's modulus and morphology. The geometries of the micro structures were analyzed by scanning electron microscopy before and after coating. Afterwards, the coated mold inserts were used for injection molding experiments. During the injection molding process, a conventional and a variothermal temperature control of the molds were used. The molded parts were analyzed regarding roughness, structure height and structure width by means of laser microscopy

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The manufacturing of optical components by injection molding and injection-compression molding is a serious challenge for tool and machine technology as well as for process control. To evaluate the quality of optical parts, the accuracy of the molded geometry as well as the resulting optical performance have been analyzed. At present a geometrical molding accuracy in the lower micron range has been achieved for the production of thick-walled lenses. Overall injection-compression molded lenses showed a better optical performance than injection-molded lenses. Due to these preliminary investigations, different injection-compression-molding technologies are to be examined. Thus, a mold has been developed, which enables the comparison of different injection-compression technologies. The compression step is realized, on the one hand, by the mold motion of the injection molding machine and, on the other hand, by integrated hydraulic pistons. With this mold design, the compression technique using integrated hydraulic pistons achieves better results regarding the optical and the geometrical properties of the lenses. To analyze the molded optics, a Shack–Hartmann sensor was used in order to characterize the deformation of the wave front. For the geometrical accuracy of the molded lenses, a chromatic sensor was used.