• Journal of the Korean Society for Precision Engineering
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• v.25 no.11
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• pp.45-51
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• 2008

Successive micro-scale V-grooves and a grid of pyramids were machined by elliptical vibration tufting (EVC) to investigate feasibility of using EVC as an alternative method of creating micro-molds to photo-lithography and electroforming, which have been commonly employed. An elliptical vibration grooving machine was developed which consists of two orthogonally-arranged piezoelectric actuators, a diamond cutting tool, and a motorized xyz stage. The micro-scale features were machined on materials of copper, duralumin, nickel, and hastelloy and it was found that EVC significantly reduces cutting resistance and prohibits generation of side burrs and rollover burrs, thus resulting in improving machining qualify of micro-molds in ail experimented workpiece materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.186-190
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• 2004

By this time, a mold with nano size pattern was produced using a fabrication of X-ray lithography method and in a m icro size's case it was produced using fabrication of Deep UV lithography. In this paper, we produced mold with 400 $\mu{m}$depth pattern using a new technology of SLS(Selective Laser Sintering) Rapid Prototyping method. In addition to enhance strength and thermal stability, we produced Ni structure with a thickness of 300 $\mu{m}$ on a surface of mold using electro forming method.

• 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 Institute of Surface Engineering Conference
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• 2015.11a
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• pp.344-345
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• 2015

Various concentration of copper was dopped in Fe-35%Ni thin sheet by electroforming and their electromagnetic, surface properties were determined. Microstructure observation by scanning electron microscopy revealed that the thin sheet had columnar grains with about 150 nm long. Phase analysis by X-ray diffractometry revealed that the alloy thin sheets were fine crystalline. The average surface roughnesses measured by atomic force microscopy (AFM) were about 14.38 nm. Nano hardnesses determined by tribo-nano indenter were 4.13 GPa. The surface resistances were 2.28 ohm/sq. The maximum magnetization, residual magnetization and coercive force depended on the copper concentration.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.236-241
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• 2004

UV-molded microlens arrays with high replication quality were fabricated using a parametric design method. It is important to maximize the replication quality, because one can obtain the replicated micro-optical components with desired properties by accurate control of the shape. In the present study, nickel mold inserts for microlens arrays with lenses having diameters between $3\mu\textrm{m}$ and $230\mu\textrm{m}$ were fabricated by electroforming process. An UV-molding system was designed and constructed, a simple technique to avoid micro-air bubbles was first suggested, and the effects of the compression pressure and UV-curing dose on the replication quality of UV-molded microlens arrays with a diameter of $14\mu\textrm{m}$ were examined experimentally. Finally, geometrical and optical properties of the replicated microlens arrays were measured and analyzed.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.370-375
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• 2002

Recently, the interest on micro optical parts has increased rapidly with the development of technology related to microsystems. Among the optical parts, micro lens is one of the most broadly used micro parts. To mass-produce the micro lenses, it is very effective to use the mold insert and injection molding process. There are many methods to fabricate the mold insert for micro lenses: electroforming, etching, mechanical micromachining and so on. In this study, we fabricated the mold insert for micro lenses using a micro ball endmill to apply mechanical micromaching method and analyzed the effect of main process parameters such as spindle speed, feed rate, dwell time on the processed surface. Then, using fabricated the mold insert we fabricated the micro lenses through injection molding process.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2011.05a
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• pp.63-64
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• 2011

니켈 알러지를 일으키지 않는 전주 부품 개발을 위해 Ni을 대체할 수 있는 전주 소재로 Ni-Fe 합금과 Fe에 대한 전주 공정을 개발하였다. Ni-Fe 합금 전주의 경우 전주품의 표면 내식성 강화를 위해 Cr 나노입자를 이용한 복합전주를 실시하여, Ni 전주품과 내부식성, 니켈 용출 비교 분석 실험을 하였다. 또한 Ni을 완전히 배제하기 위해 새로운 시도로서 순 Fe 전주 공정 기술을 개발하였다. 제조된 Fe 전주품의 내식성 향상을 위한 실리카 코팅 등의 표면처리에 대한 효과도 분석하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.94-97
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• 2008

현재 전주 국내에서는 전주에 대한 관심이 조금씩 증가하는 추세지만 그 활용 영역은 많지 않다. 최근들어 휴대폰 관련 부품과 LCD디스플레이의 핵심부품인 도광판 사출금형에 집중되어 있다. 본 연구에서는 반도체 웨이퍼 절단용 블레이드 제작을 목표로 Ni 전주도금층에 조밀하게 $Al_2O_3$를 분산시키는데 목표를 삼았다. 전주(electroforming)를 이용한 Ni-$Al_2O_3$를 첨가한 설파민산 니켈욕에 Surfactant의 양을 조절하며 Sodium Lauryl Sulfate의 첨가량이 많아질수록 Nickel 전주도금층 표면에 $Al_2O_3$는 접착되어지지 않고, 도금층의 두께는 두꺼워졌다. Surfactant의 첨가로인하여 Ni 전주도금층의 표면 장력이 감소하여 $Al_2O_3$를 감싸고 Ni 전주도금층이 성장하여야하는데 교반하는 과정에서 $Al_2O_3$ 입자들이 용액의 흐름에 따라 떨어져 나갔다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.60-63
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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. Finally, the nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. The replicated patterns using nano-injection molding process were as small as 50 nm in diameter, 150 nm in pitch, and 50 nm in depth.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.23-28
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• 2005

Microlens arrays were fabricated using a modified LIGA process based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, the hot embossing and the microinjection molding processes have been successfully utilized with the fabricated mold insert. Fabricated microlenses showed good surface roughness than the mold insert. The focal lengths of the injection molded microlenses were successfully measured experimentally and also estimated theoretically.