• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.605-609
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• 1996

In order to ensure that the prototype corresponds as closely as possible to the serial part subsequently to be manufactured, the materials used for the prototye should, wherever possible, be identical to those used in production. In case of metallic parts, however, this demand is still not completely fulfilled by the available Rapid Prototyping techniques. Since only conventional manufacturing processes caan currentlybe used to produce metallic prototypes directly, these are extremely cost and labor intensive. For this reason, work is being undertaken worldwide to develop Selective Laser Sintering (referred to SLS) and Laser Generating for direct manufacture of metallic parts. In this paper the results of both process developments are reported. As the present results show, they have great application potentials in prototyping tools, especially molds and dies.

• Corrosion Science and Technology
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• 제15권2호
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• pp.78-83
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• 2016

The e-coating to inhibit induced corrosion can deposit a coating not only on the exterior surface but also on the inside of whole metallic components of body-in-white (BIW). But it is difficult to deposit paint films on the inside area because metallic components are multi layered. It may cause shortness of e-coating thickness. The only way to properly verify e-coating thickness is by performing the use of tear-down prototypes. When paint films' thickness is inadequate, a structural modification on each metallic component is needed. Verification of the thickness improvement for a structural modification requires much manual effort and leads to increasing development time. Recently, the simulation technology has been developed to predict the e-coating thickness in e-coating field. By applying the simulation to BIW, improvement in paint thickness quality and shortening of development period are expected. The paper explains a validated solution that allows simulating the effect of design changes to the e-coating thickness and current density, thereby delivering results within a time frame of a few days.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.191-194
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• 1995

The business of manufacturing is increasingly becomeing time-compresssing, precise and long-life oiented, owing to various needs form the consumers and harsh global competition. with the emergence of the layer laminate maunfacturing methods, it is possible to prototypes directly from 3D CAD and additive process, the production time and cost have shortened dramatically. However there are some problems like surface-step, dimensional deviation and warp. A newly developed powder casting is suitable for rapid-manufacturing metallic tools. Powder casting can serve as a promising repid tooling method because of high density charateristics and low dimensional shrinkage below 0.1% during sintering and infiltration. By this process, we have realized significant time savings bypassing the wait for prototype tooling and cost savings eliminating the expense of conventional prototype tooling process.

• 한국정밀공학회지
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• 제15권7호
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• pp.85-90
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• 1998

The business of manufacturing is increasingly becoming time-compressing, precise and long-life oriented, owing to various needs from the consumers and harsh global competition. With the emergence of the layer laminate manufacturing method, it is possible to produce prototypes directly from 3D CAD and additive process, the production time and cost have shortened dramatically. However there are some problems like surface-step, dimensional deviation and warp. A newly developed powder casting is suitable for rapid-manufacturing metallic tools. Powder casting can serve as a promising rapid tooling method because of high density characteristics and low dimensional shrinkage below 0.1％ during sintering and infiltration. By this process, we have realized significant time savings bypassing the wait for prototype tooling and cost savings eliminating the expense of conventional prototype tooling process.

• 한국콘텐츠학회논문지
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• 제14권1호
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• pp.1-13
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• 2014

오늘날 소비자의 요구가 점점 다양해지고 신제품 개발 사이클이 짧아짐에 따라 쾌속조형기술이 점차로 광범위하게 사용되고 있다. 본 연구에서는 일반적으로 CAD/CAM기술의 활용도가 점차 증대되고 있는 귀금속분야에 사용되는 쾌속조형기술을 전통상감기법을 사용한 공예상품의 상감베이스를 제작하기 위하여 적용하였다. 쾌속조형기술은 상감베이스를 제작하는 데 있어 기존의 전통수공예 기법으로 제작된 상감베이스보다 정밀하고 균일하며 다양한 입사 홈을 제작 할 수가 있어 보다 정교한 언더컷 형상과 균일한 상감디자인을 형상화 할 수가 있었다. 따라서 본 연구에서는 쾌속조형기술을 통하여 상감베이스 입사홈 가공에 있어 보다 단시간에 작업자의 숙련도에 크게 좌우되지 않고 균일한 문양과 다양한 곡선 상에 입사홈을 가진 상감베이스를 제작할 수가 있었고 이는 품질, 비용, 납기 측면에서 보다 개선된 상감베이스를 제작 할 수가 있었다.

• Progress in Superconductivity
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• 제4권1호
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• pp.1-9
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• 2002

Transferring single flux quanta across a Josephson junction at an exactly determined rate has made highly precise voltage measurements possible. Making use of self-shunted Nb-based SINIS junctions, programmable fast-switching DC voltage standards with output voltages of up to 10 V were produced. This development is now extended from fundamental DC measurements to the precise determination of AC voltages with arbitrary waveforms. Integrated RSFQ circuits will help to replace expensive semiconductor devices for frequency control and signal coding. Easy-to-handle AC and inexpensive quantum voltmeters of fundamental accuracy would be of interest to industry. In analogy to the development in the flux regime, metallic nanocircuits comprising small-area tunnel junctions and providing the coherent transport of single electrons might play an important role in quantum current metrology. By precise counting of single charges these circuits allow prototypes of quantum standards for electric current and capacitance to be realised. Replacing single electron devices by single Cooper pair circuits, the charge transfer rates and thus the quantum currents could be significantly increased. Recently, the principles of the gate-controlled transfer of individual Cooper pairs in superconducting A1 devices in different electromagnetic environments were demonstrated. The characteristics of these quantum coherent circuits can be improved by replacing the small aluminum tunnel Junctions by niobium junctions. Due to the higher value of the superconducting energy gap ($\Delta_{Nb}$ ＝ $7\Delta_{Al}$), the characteristic energy and the frequency scales for Nb devices are substantially extended as compared to A1 devices. Although the fabrication of small Nb junctions presents a real challenge, the Nb-based metrological devices will be faster and more accurate in operation. Moreover, the Nb-based Cooper pair electrometer could be coupled to an Nb single Cooper pair qubit which can be beneficial for both, the stability of the qubit and its readout with a large signal-to-noise ratio..