• Journal of Korea Foundry Society
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• v.22 no.5
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• pp.265-270
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• 2002

A novel jewelry master pattern manufacturing process which reduce manufacturing steps by employing a Duraform rapid prototyping mold and a low melting alloy has been suggested. The novel process follows the steps of 'jewelry 3D CAD design ${\rightarrow}$ Durafrom RP mold ${\rightarrow}$ low melting alloy master pattern' while the previous process follows more complicated steps of 'jewelry idea sketch ${\rightarrow}$ detailed drawing ${\rightarrow}$ wax carving ${\rightarrow}$ flask ${\rightarrow}$ silver master pattern.' An upper and a lower part of molds have been manufactured of Duraform powder, of which melting point is $190^{\circ}C$. A maser pattern was manufactured by pouring a low melting alloy of Pb-Sn-Bi-Cd, so called Woods Metal, of which melting point is $70^{\circ}C$, into the mold. The master pattern is a shape of a disk of 20mm diameter that contains various design factors. The variations of dimensions, surface roughness, surface pore ratio were measured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of were maeasured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of low melting alloy has sufficient surface hardness, and surface pore ratio to be used as the jewelry master pattern.

• Journal of the Korean Vacuum Society
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• v.19 no.2
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• pp.96-104
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• 2010

We suggest here a cost-effective replica fabrication method for transparent and hard molds for imprinting lithography such as NIL and S-FIL. The process starts with the use of a replica hard mold from a master, using a polymer copy as a carrier. The polymer copy as a carrier was treated by soluble process for forming anti-adhesion layer. Duplicated hard molds can eliminate direct contact between a hard master and a patterned polymer on a substrate and the generated contamination of a master during the imprinting process. The replica hard mold exhibits the glass-like properties introduced here, such as transparency and hardness, make it appropriate for nanoimprint lithography and step-and-flash imprint lithography.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.12
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• pp.13-20
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• 2004

Manufacturing process for the microfluidic device can include such sequential steps as master fabrication, electroforming, and injection molding. The laser ablation using masks has been applied to the fabrication of channels in microfluidic devices. In this study, manufacturing of polymer master and mold insert for micro injection molding was investigated. Ablation of PET (polyethylene terephthalate) by the excimer laser radiation could be used successfully to make three dimensional master fur nickel mold insert. The mechanism fur ablative decomposition of PET with KrF excimer laser $({\lambda}: 248 nm, pulse duration: 5 ns)$ was explained by photochemical process, while ablation mechanism of PMMA (polymethyl methacrylate) is dominated by photothermal process, the .eaction between PC (polycarbonate) and KrF excimer laser beam generate too much su.face debris. Thus, PET was adopted in polymer master for nickel mold insert. Nickel electroforming using laser ablated PET master was preferable for replication method. Finally, it was shown that excimer laser ablation can substitute for X-ray lithography of LIGA process in microstructuring.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.96-102
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• 2006

In this study, manufacturing of polymer master, PDMS(poly dimethylsiloxane) transfer mold, and mold insert was investigated for laser LIGA(LIthography Calvanoformung Abformtechnik). Initially, ablation by excimer laser radiation was used successfully to make 3-D microstructure of PET. After then, the PDMS transfer mold was replicated using ablated PET. Finally, epoxy resin tooling on replicated PDMS transfer mold was executed for making mold insert. From these facts we can conclude that excimer laser ablation of polymer and fabricaiton of PDMS transfer mold are reasonable tools to substitute for X-ray lithography of LIGA process in microstructuring.

• Laser Solutions
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• v.6 no.2
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• pp.35-41
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• 2003

In this study, manufacturing of polymer master and mold insert for micro injection molding was investigated. Ablation by excimer laser radiation could be used successfully to make 3-D microstructure of PET. The mechanism for ablative decomposition of PET with KrF excimer laser(λ: 248nm, pulse duration: 5ns) was explained by photochemical process. And this process showed PET to be adopted in polymer master for nickel mold insert. Nickel electroforming by using laser ablated PET master was preferable for replication method. Finally, it was shown that excimer laser ablation can substitute for X-ray lithography of LIGA process in microstructuring.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.316-319
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• 2007

In this paper, high precision molding process was developed using a soft mold to fabricate fine closed-types of the barrier ribs for PDP. A green sheet was employed to fabricate the barrier ribs in this process. The soft mold with good demolding characteristics was replicated from a master mold. An optimal forming load which would not fracture the soft mold was also determined. The barrier ribs of rectangular type with upper width of $30\;{\mu}m$ would be fabricated by this process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.3
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• pp.223-226
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• 2004

Injection molding using plastic materials was expected to mass production of structure with nano pattern for low cost phase. The PDMS mold was produced easily and uniformly by using thermal embossing. Quartz master for embossing method was made using electron beam lithography it had 100-500 nm size of line and dot type. The PDMS mold was produced after a brief hardening process and the master removal. The results show that various patterns are successfully fabricated the nano scale.. The replicated mold would be useful a stamper fabrication for injection molding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.435-436
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• 2010

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.710-713
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• 2005

In this study, waffle type barrier ribs for counter electrode discharge cells were prepared via micro-molding process. The master mold was prepared by UV lithography and working mold was manufactured by replicating the master mold. The UV paste used in this study consisted of ceramic powders for the barrier ribs, binder, hardener, and dispersant was filled into cavities of a polymeric mold by action of capillary pressure developed between mold and paste. The results demonstrated a possibility of one-step process for the manufacturing of waffle type barrier ribs embedded with sustaining electrodes.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.729-734
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• 2015

Improvement in the control strategy for continuous casting is a crucial requirement to enhance the slab's quality and to increase productivity. The mold oscillator adopts the dual cylinders due to its heavy weight, so the synchronized motion of two cylinders is an important aspect when precise control is needed. The conventional method uses the master-slave control applied to the valve input reference, but the synchronization performance should still be improved. This paper proposes a novel synchronization algorithm for dual cylinders used in a mold oscillator. The master-slave concept is applied to the target reference position, that is, the slave target reference position is controlled to match the slave cylinder's position with the master cylinder's position. In the simulation based on a Simulink model, the proposed algorithm shows a better synchronization performance in aspect of the mean of the absolute error and the peak synchronization error.