• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.632-635
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• 2003

As a process technology of nano pattern with a new conception for economic and practical technology of alternative nano process. process technologies such as Embossing, Imprinting. Molding and Inking are beginning to make its appearance. Among these alternative processes, nano mold process is a process that is of benefit to mass production and keeps excellency of reproduction and high quality of parts. In this study, we experienced micro precision machining technology of nano stamper for the injection mold of optical disk with big capacity. Especially, Flatness and uniformity are important for nano stamper with global area, for the purpose of developing polishing technology of micro precision of Back polishing only being used for nano stamper, we carried out a basic study to secure flatness standards

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.8-13
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• 2015

In this study, we fabricated and characterized a nanostructured surface based on a plastic injection molding with a local mold heating (LMH) system. A metal mold core with a closed packed nano convex array (CVA) was achieved by integrated engineering procedures: (1) master template fabrication by anodic aluminum oxidation (AAO), (2) nickel electroforming (NE) process, and (3) post-processing by precision machining. The nickel mold core was utilized to replicate a surface with a closed packed nano concave-array (CCA) based on injection molding using cyclic olefin copolymer (COC) as a plastic material. In particular, an LMH system was introduced to enhance transcription quality of the nano structures by delaying solidification of molten polymer near the surface of the mold core.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.192-196
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• 2005

In this paper, we investigated the possibility of replicating patterned media by nano-injection molding process with a metallic nano-stamper. The original nano-master was fabricated by E-beam lithography and ICP etching process. The metallic nano-stamper was fabricated using a nanoimprint lithography and nano-electroforming process. The nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. In nano-injection molding process, since the solidified layer, generated during the polymer filling, deteriorates transcribability of nano patterns by preventing the polymer melt from filling the nano cavities, an injection-mold system was constructed to actively control the stamper surface temperature using MEMS heater and sensors. The replicated polymeric patterns using nano-injection molding process were as small as 50 nm in diameter, 150 nm in pitch, and 50 nm in depth. The replicated polymeric patterns can be applied to high density patterned media.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.113-116
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• 2006

Some nano hair systems in the nature are found to show excellent adhesive characteristic, which is called dry adhesive, and synthetic nano hairs to mimic these adhesiveness are believed to have many applications. To develop a practical synthetic dry adhesive system, we mold nano hairs on plastic substrates using thermoplstic materials including COC, PP, PC and PMMA. and estimate the moldability and the adhesive characteristic. As a template for molding nano hairs, AAO membrane is first adopted, which is 60um thick and 13mm in diameter. This membrane has about a billion of through-holes of which diameter is around 200nm. This AAO membrane and the pellet of materials are stacked in the mold and pressed to mold after heating up to be melted. The AAO membrane is removed using KOH to obtain the molded nano hairs. As a result, the diameter of the molded hairs is around 200nm and the length is $2um{\sim}60um$ depending on the molding conditions and materials. The molded nano hair substrates is estimated to show much better adhesive characteristic than a substrate without nano hairs.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.138-145
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• 2006

An injection molding is necessary to mass-product for micro-nano system, so micro-nano mold must be developed for injection molding. The micro-nano mold has precision and strength to overcome a surround of injection. So in this paper, two methods were used. First, after etching the Al, Ni was electroplated in etched AI. The other, LIGA method was used. A temperature and thickness of Ni are important factors in these methods. So after fabrication, the simulation was processed to find optimal thickenss of Ni and temperature.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.2
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• pp.63-67
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• 2018

Recent mold industry uses many roll-to-roll processes that can produce high production speed and precision machining and automation process. In the circular cylinder mold, however, patterns of less than $10{\mu}m$ are difficult to manufacture and maintain. In this study, we fabricated a circular cylindrical mold with a DLC thin film which have high hardness, low coefficient of friction and high releasability by using lithography and lift-off process. The height, line width, and pitch of the fabricated DLC macro pattern are $3.1{\mu}m$, $9.1{\mu}m$ and $20.2{\mu}m$, respectively. The pattern size is finer than the current applied to the aluminum cylinder type, and this shows the possibility of practical use of DLC micro pattern roll mold.

• Korean Journal of Materials Research
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• v.31 no.6
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• pp.331-338
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• 2021

Ti-Al-Si target and Cr-Si target are sputtered alternately to develop a multi-layered nitride coating on a steel mold to improve die-casting lifetime. Prior to the multi-layer deposition, a CrN layer is developed as a buffer layer on the mold to suppress the diffusion of reactive elements and enhance the cohesive strength of the multi-layer deposition. Approximately 50 nm CrSiN and TiAlSiN layers are deposited layer by layer, and form about three ㎛-thickness of multi-layered coating. From the observation of the uncoated and coated steel molds after the acceleration experiment of liquid metal injection casting, the uncoated mold is severely eroded by the adhesion of molten metallic glass. On the other hand, the multi-layer coating on the mold prevents element diffusion from the metallic glass and mold erosion during the experiment. The multi-layer structure of the coating transforms the nano-composite structured coating during the acceleration test. Since the nano-composite structure disrupts element diffusion to molten metallic glass, despite microstructure changes, the coating is not eroded by the 1,050 ℃ molten metallic glass.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.633-634
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.19-20
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• 2010

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.4
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• pp.332-335
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• 2008

PMMA light guiding plate with nano pattern was fabricated by nano imprint lithography method. A silicon mold for electroplating of nickel was fabricated by conventional photolithography process. A nickel stamp for nano imprint lithography was fabricated by electroplating process using silicon mold. The nano imprint lithography was performed on PMMA plate at $140^{\circ}C$ under pressure of 20kN. The nano pattern on PMMA plate was investigated using FE-SEM. It is shown that the patterns were well transferred for several steps and the nano imprint lithography method could be applied for fabricating patterns of light guiding plate.