• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.21-22
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• 2023

In order to manufacture high-quality free-form concrete panel (FCP), it is necessary to analyze the limitations of free-form silicone mold (FSM) and conduct technology development research. Currently, the FSM used in FCP manufacture is classified into a side silicon mold(SSM) and a lower silicon mold(LSM). In this study, the limitations of each silicon mold were analyzed and solutions were proposed. In the case of side silicon mold, there is a limit to cannot supporting the side pressure of concrete. Therefore, a mold stacking method was proposed, and at the same time, a process of correcting the movement value of the rod was proposed. In the case of the lower silicon mold, there is a limit to completely implementing the design shape. Therefore, a real-time scanning method and a process of displaying FCP shape coordinates were proposed. The results of this study are expected to be used as basic data for manufacturing high-quality FCP.

• 한국주조공학회지
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• 제4권2호
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• pp.102-107
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• 1984

The variations of the mold compression strength were studied by varing the contents of the silicon powder and water glass, silion purities, and molecule rates of the water glass, when domestic JA EUN DO sand is mixed with water glass (sodium silicate) and metallic silicon or ferro - silicon powder by the self - hardening N - PROCESS method. The results obtained from this experiment are as follows; 1) The compression strength of the mold used with metalic powder was higher and more stable than to be used ferro - silicon powder. 2) 6% water glass of 2.8 molecule rate and 1.5% of ferro - silicon of 75% purity for the N - PROCESS used with JA EUN DO sand was suitable mixing rate. 3) The compression strength increased with self - hardening time, and the PH values of the mixture of silicon powder and water glass did not change after 2 hours, but the compression strength increased steadily due to the reaction of remained silicon. 4) It is recommended to take 24 hours for self - hardening time at least.

• 한국생산제조학회지
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• 제21권6호
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• pp.998-1002
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• 2012

This paper investigates the behavior of bubbles trapped in the in-mold coating (IMC) process. Silicon oil with different viscosity, 100, 150, 200, 300 and 400cps, was selected instead of the coating materials. To observe the flow front inside, a special mold was designed, where front plate was made of transparent material (acrylate). The overall size of front plate was $150mm{\times}120mm$. Mold gate location can be changed from up to down. Four heaters were used to investigate the effectiveness of temperature. The results show that silicon viscosity, mold gate location and mold temperature play an important role on the appearance of bubbles trapped in IMC process.

• 한국정밀공학회지
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• 제28권8호
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• pp.966-974
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• 2011

The use of ion beams in the micro/nano scale is greatly increased by technology development. Especially, focused ion beams (FIBs) have a great potential to fabricate the device in sub micro scale. Nevertheless, FIB has several limitations, surface swelling in low ion dose regime, precipitation of incident ions, and the redeposition effect due to the sputtered atoms. In this research, we demonstrate a way which can be used to fabricate mold structures on a silicon substrate using FIBs. For the purpose of the demonstration, two essential subjects are necessary. One is that focused ion beam diameter as well as shape has to be measured and verified. The other one is that the accurate rotational symmetric model of ion-solid interaction has to be mathematically developed. We apply those two, measured beam diameter and mathematical model, to fabricate optical lenses mold on silicon. The characteristics of silicon mold fabrication will be discussed as well as simulation results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1073-1077
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• 2003

This study aims to investigate the fabrication process of nano silicon mold using electron beam lithography (EBL) to generate the nanometer level patterns by nano-imprinting technology. the nano-patterned mold including 100mm pattern size has been fabricated by EBL with different doses ranged from 22 to 38 ${\mu}C/cm^2$ on silicon using the conventional polymethylmetharcylate(PMMA) resist. The silicon mold is fabricated with various patterns such as circles, rectangles, crosses, oblique lines and mixed forms, The effect of dosage on pattern density in EBL is discussed based on SEM (Scannning Electron Microscopy) analysis of fabricated molds. The mold surface is modified by hydrophobic fluorocarbon (FC) thin films to avoid the stiction during nano-imprinting process.

• 한국정밀공학회지
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• 제18권3호
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• pp.75-83
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• 2001

RIM(Reaction Injection Molding) is a widely used method to manufacture middle-large size outfit-part for a prototype car. The main advantage of RIM is the capability of manufacturing a small number of prototype parts with less cost and lead time than injection molding which is the most popular method to manufacture plastic parts. Generally, epoxy resin and RTV(Room Temperature Vulcanization) silicon are used as mold materials for RIM, and the selection of mold materials is usually depended upon the industrial environment of manufactures and it decides overall mold making process and part quality. This paper suggests a new mold making process by consolidating the advantages of epoxy resin and RTV silicon based RIM mold to enhance the parts quality while reducing the manufacturing cost and time and shows the competitiveness of the suggested process compared with conventional methods.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.6-7
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• 2021

Although the development of free-form architectural technology continues, it consumes a lot of money and time due to the one-time formwork and the difficulty of maintaining quality due to manual work. To this end, in this study, a shape connection technique was proposed and verified to improve the limitations of implementing the curved surface of the existing lower multi-point press. In order to improve the accuracy of the shape, a curved surface was implemented using a silicon cap and a silicon plate. As a result of the error analysis of the shape, a small value of less than 3 mm was found. This study can implement more accurate curved surfaces than conventional technologies and produce high-quality free-form panels.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.351-354
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• 2004

This work presents a simple and cost-effective approach for maskless fabrication of positive-tone silicon master for the replica molding of hyperfine elastomeric channel. Positive-tone silicon masters were fabricated by a maskless fabrication technique using the combination of nanoscratch by Nanoindenter ⓡ XP and XOH wet etching. Grooves were machined on a silicon surface coated with native oxide by ductile-regime nanoscratch, and they were etched in a 20 wt％ KOH solution. After the KOH etching process, positive-tone structures resulted because of the etch-mask effect of the amorphous oxide layer generated by nanoscratch. The size and shape of the positive-tone structures were controlled by varying the etching time (5, 15, 18, 20, 25, 30 min) and the normal loads (1, 5 mN) during nanoscratch. Moreover, the effects of the Berkovich tip alignment (0, 45$^{\circ}$) on the deformation behavior and etching characteristic of silicon material were investigated.

• 제어로봇시스템학회논문지
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• 제14권4호
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• pp.361-364
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• 2008

Tips of probe card were fabricated using MEMS technology. P-type silicon wafer with $SiO_2$ layer was used as a substrate for fabricating the probe card. Ni-Cr and Au used as seed layer for electroplating Ni were deposited on the silicon wafer. Line patterns for probing devices were formed on silicon wafer by electroplating Ni through mold which formed by MEMS technology. Bridge structure was formed by wet-etching the silicon substrate. AZ-1512 photoresist was used for protection layer of back side and DNB-H100PL-40 photoresist was used for patterning of the front side. The mold with the thickness of $60{\mu}m$ was also formed using THB-120N photoresist and probe tip with thickness of $50{\mu}m$ was fabricated by electroplating process.

• 한국주조공학회지
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• 제26권4호
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• pp.174-179
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• 2006

This study aims to investigate the microstructures and mechanical properties of DCI manufactured by sand and metal mold casting. To prohibit the formation of the chill, carbon, silicon and rare earth($0{\sim}0.2\;wt%$) were controlled and temperature of metal mold was constantly kept at $160^{\circ}C$. The sizes, counts and nodularity ratios of nodules were analyzed by image analysis device. Wear test using pin-on-disc wear tester was carried out under the conditions of load 47.2N, velocity 0.4 m/s and distance 2000 m. Tensile test using Instron type testing machine was performed with velocity of 0.1 mm/min according to the KS B 0802. The formation of the chill was not observed when percentage of the carbon and silicon were 3.8 and 2.5. Mechanical properties of GCD manufactured by metal mold were better than sand casting.