• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1128-1131
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• 2004

SFF(solid freeform fabrication) is another name of RP(rapid prototyping). The SFFS for office type wishes to develop system that can produce small object such as hand phone, cup, accessory etc. with high speed, and also intend suitable system in office environment by compact design, and buy easily by inexpensive price. As can manufacture high speed in existent SFF process technology, representative process that have competitive power in price is 3DP (three dimensional printing) technology. The 3DP technology is way to have general two dimensional printing technology and prints to three dimension, is technology that make three-dimensional solid freeform that want binder doing jetting selectively on powder through printer head. We designed and manufactured SFFS for office based on 3DP process technology design and manufactured, and composed head system so that use 3 printer heads at the same time to improve the fabrication speed of system. We used printer head of INCJET company and cartridge used HP45 series model who can buy easily in general city. And we directly fabricated three dimensional solid freeform using developed SFFS for office type.

• 한국가시화정보학회:학술대회논문집
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• 2007.11a
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• pp.128-133
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• 2007

An electrostatic inkjet head can be used for manufacturing processes of large display systems and printed circuit boards (PCB) as well as inkjet printers because an electrostatic field provides an external force which can be manipulated to control sizes of droplets. The existing printing methods such as thermal bubble and piezo inkjet heads have shown difficulties to control the ejection of the droplets for printing applications. Thus, the new inkjet head has been proposed using the electrostatic force. A numerical analysis has been performed to calculate the intensity of the electrostatic field using the Maxwell's equation. Also, experiments have been carried out to investigate the droplet movement using a downward capillary with outside diameter of $500{\mu}m$. Gravity, surface tension, and electrostatic force have been analyzed with high voltages for a drop-on-demand ejection. It has been observed that the droplet size decreases and the frequency of the droplet formation and the velocity of the droplet ejection increase with increasing the intensity of the electrostatic field using high-speed camera.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.8
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• pp.1445-1449
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• 2007

This paper presents the DOD (Drop-On-Demand) characteristic using the electrostatic field induced inkjet printing system. In order to achieve the DOD characteristic of electrostatic field induced inkjet printing, applied the bias voltage of 1.4 kV and the pulse voltage of $2.0\;kV\;{\sim}\;2.7\;kV$ using high voltage pulse generator. Electrostatic field induced droplet ejection is directly observed using a high-speed camera and for investigated DOD characteristic, CNT ink used. The electrostatic field induced inkjet head system has DOD characteristic using pulse generator which can be applied pulse voltage. The bias voltage has a good condition which form meniscus and has micro dripping mode for small size micro droplet. Also, the droplet size decreases with increasing the applied pulse voltage. This paper shows DOD characteristic at electrostatic field induced inkjet head system, Therefore. electrostatic DOD inkjet head system will be applied industrial area comparing conventional electrostatic inkjet head system.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.92-92
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• 2012

나노필라멘트 섬유는 직편물 등으로 구조/용도 다양화 가능하다. 나노필라멘트 섬유는 소재특유의 닦음성, 흡착성, 고밀도 특성 등을 활용하여 직편물의 형태로 다양한 용도 개발이 가능하며, 나노기술을 접목시킨 새로운 기능성과 고성능 섬유 소재 개발을 통한 자동차 분야의 개발 트랜드인 고급화, 경량화, 고성능화 추진을 위해 연료전지, 신슐레이터, 고성능 필터, 시트나 도어트림, 헤드라인과 같은 인테리어류와 전자 분야의 제조원가 절감, 공정 단순화를 위해 프린터 토너, 하드디스크 연마제, 다용도 No Dust Cleaner 등의 개발, 의료/바이오 분야의 혈액필터, 수술용 보호제, 창상억제제(유착 방지막), 항균마스크, 의료용 약물전달 시스템 및 환경 분야의 정수/공기 정화 시스템, 건축 토목용 보강제, 고(高)인성 콘크리트, 폐수처리용 슬러리 담체(Matrix) 등 다양한 분야로 용도 개발이 가능하다. 본 연구는 나노필라멘트의 다양한 분야로의 용도 개발 적용의 기초연구로서, 부직포 상으로 얻어지는 나노섬유 제조기술의 단점인 직경의 불균일, 물리적 특성의 한계와 필라멘트가 아닌 단섬유로 인해 발생하는 용도 및 상품 개발에의 제한성을 개선하기 위하여 연속적으로 필라멘트를 생산가능한 해도형 복합방사 방법을 도입하여 개발한 장섬유 필라멘트 형태의 해도형 나노 섬유 소재를 활용하는 것으로 방사된 SDY 형태의 나노필라멘트 섬유를 제직상에서의 작업성 용이 및 직물의 벌키성 증대와 Crimp성을 향상 시켜 터치감 및 후가공에 용이할 수 있도록 DTY를 제조함에 있어 기존 일반 POY사에서의 DTY공정과는 달리 소재의 특성 즉, 해도사의 해성분 및 도성분의 후공정을 감안하여 최적의 Crimp는 발현하되 단면의 형상을 유지할 수 있는 다양한 사가공 조건을 설정 하고 이에 따라 가공사를 생산하여 공정조건에 따른 가공사의 물성 및 수축특성을 비교 분석 하여 염색 및 후가공시 소재의 물성 및 수축특성이 미치는 영향성을 살펴보고자 하였다.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.3
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• pp.1-7
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• 2003

The crystallized stable cobalt silicide$(CoSi_2)$ films were prepared on $poly-Si/SiO_2/Si$substrates for the application of inkjet printing head as a heating element with omega shape. The structural images and temperature resistance coefficient were investigated. The value of temperature resistance coefficient of the heating element was found to be about $0.0014/^{\circ}C$. The maximum power of the heating element was 2 W at the applied voltage of 2 V, 10 kHz in frequency and $1{\mu}s$ in pulse width. From the investigation of fatigue property according to the repeated applied voltages, there was no drastic changes in the resistances of heating element under the condition of $10^8$ pulsed cycles at below 15 V biased voltage. In contrast, the resistance of heating element was greatly increased at $10^6$ pulsed cycles when the heating element was operated at 17 V.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.5 s.248
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• pp.413-421
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• 2006

The bubble dynamics induced by direct laser heating is experimentally analyzed as a first step to assess the technical feasibility of laser-based ink-jet technology. To understand the interaction between laser light and ink, the absorption spectrum is measured for various ink colors and concentrations. The hydrodynamics of laser-generated bubbles is examined by the laser-flash photography. When an Ar ion laser pulse (wavelength 488 nm) with an output power up to 600 mW is incident on the ink solution through a transparent window, a hemispherical bubble with a diameter up to ${\sim}100{\mu}m$ can be formed with a lifetime in a few tens of microsecond depending on the laser power and the focal-spot size. Parametric study has been performed to reveal the effect of laser pulse width, output power, ink concentration, and color on the bubble dynamics. The results show that the bubble generated by a laser pulse is largely similar to that produced by a thin-film heater. Consequently, the present work demonstrates the feasibility of developing a laser-actuated droplet generation mechanism for applications in ink-jet print heads. Furthermore, the results of this work indicate that the droplet generation frequency is likely to be further increased by optimizing the process parameters.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.101-108
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• 2021

The CT can accurately present the anatomical structure of an organ in the human body, and the resolution of the image is excellent. On Brain CT examination, the radiation sensitivity of the orbit is high and it is subject to many exposure effects. To reduce exposure dose of lens, this study compares change of exposure dose and shielding rate about non-shielding and shielding in a way of using two shielding materials, bismuth and tungsten. In this study, we used bismuth and tungsten filament as shielding materials made by 3D printing to measure the exposure dose according to the materials thickness and each of slices. To compare each shielding rate, 1 mm to 5 mm of two materials was measured with the head phantom fixed and the Magicmax universal dosimeter placed on the eye when the shielding material is not placed, and the shielding material is placed on it. In the 1 mm thick filament, the bismuth filament showed 26.8% and the tungsten filament showed 43.1% shielding rate. Therefore, tungsten presents much greater shielding effect than bismuth.

• Journal of the Korean Ceramic Society
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• v.40 no.7
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• pp.657-661
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• 2003

The elastic moduli or fracture strengths of multi-layered film (SiO$_2$/po1y-Si/SiN/SiO$_2$, 2.77 $\mu\textrm{m}$ thick), CVD diamond film (1.6 $\mu\textrm{m}$ thick), SiO$_2$ film (1.0 $\mu\textrm{m}$ thick) and SiN film (0.43 $\mu\textrm{m}$ thick) made for the membrane of ink-jet printer head were measured with cantilever beam bending method using nanoindenter after fabricating in the form of micro cantilever beam (${\mu}$-CLB). And the elastic moduli of ${\mu}$-CLB of SiO$_2$ film and SiN film were compared with the value of each film on silicon substrate determined with nanoindentation method. The results showed that the modulus and strength of multi-layered film decrease from 68.08 ㎬ and 2.495 ㎬ to 56.53 ㎬ and 1.834 ㎬, respectively as the width of CLB increases from 18.5 $\mu\textrm{m}$ to 58.5 $\mu\textrm{m}$. And the elastic moduli of SiO$_2$ and SiN films measured with ${\mu}$-CLB bending method are 68.16 ㎬ and 215.45 ㎬, respectively and the elastic moduli of these films on silicon substrate measured with nanoindentation method are 98.78 ㎬ and 219.38 ㎬, respectively. These results show that with ${\mu}$-CLB bending technique, moduli can be measured to within 2%.