• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1885-1888
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• 2003

As high technology industries such as IT and display have developed, demand for application parts of micro lens and lens array has been extremely increasing. According to these trends, many researchers are studying on the fabrication technology for parts of the micro lens by a variety of methods such as MEMS, Lithography, LIGA and so on. In this paper, we have performed researches related to ultra precision micro lens, lens array mold and fabrication of Lenticular lens mold for three-dimensional display by using mechanical micro end-milling and fly-cutting fabrication method. Tools used in this research were a diamond tool of R 150$\mu\textrm{m}$. Cutting conditions set up feed rate, spindle revolution. depth of cut and dwell time as variables. And we analyzed surface quality variation of the processed products according to the cutting conditions, and then carried out experiments to search the optimum conditions. Through this research, we have confirmed that we can fabricate the ultra precision micro lens mold with surface roughness Ra=20nm and the holographic lens mold by using micro end-milling and fly-cutting fabrication method. Furthermore, we demonstrated problems happened in the fabrication of the micro lens and established the foundation of experimental study for formulating its improvement plan.

• 한국정밀공학회지
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• 제24권8호통권197호
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• pp.138-143
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• 2007

Microstereolithography technology is similar to the conventional stereolithography process and enables to fabricate a complex 3D microstructure. This is divided into scanning and projection type according to aiming at precision and fabrication speed. The scanning MSL fabricates each layer using position control of laser spot on the resin surface, whereas the projection MSL fabricates one layer with one exposure using a mask. In the projection MSL, DMD used to generate dynamic pattern consists of $1024{\times}768$ micromirrors which have $13.68{\mu}m$ per side. The fabrication range and resolution are determined by the field of view of the DMD and the magnification of the projection lens. If using the projection lens with high power, very fine microstructures can be fabricated. In this paper, the projection MSL system adapted to a large surface for array-type fabrication is presented. This system covers the meso range, which is defined as the intermediate range between micro and macro, with a resolution of a few ${\mu}m$. The fabrication of array-type microstructures has been demonstrated to verify the performance of implemented system.

• 설비공학논문집
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• 제27권10호
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• pp.552-557
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• 2015

The nanostereolithography process using a femtosecond laser has been shown to have strong merits for the direct fabrication of 2D/3D micro structures. In addition, a femtosecond laser provides efficient tools for precise micromachining owing to the advantages of a small and feeble heat effect zone. In this paper, we report an effective fabrication process of 3D micro optical and fluidic devices using nanostereolithography process composed of a dual stage system. Process conditions for additive and subtractive fabrication are examined. The Piezo stage scanning system is used for 3D micro-fabrication in unit area of sub-mm scale, and the motor stage is employed in fabrication on the scale of several mm. The misalignment between the pizeo- and motor- stages is revised through rotational transformation of CAD data in the unit domain. Here, the effectiveness of the proposed process is demonstrated through examples using 3D optical and microfluidic structures.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.205-208
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• 2005

Fabrication of large scaled mirror for the telescope application is the most challenging technology in recent year. Sophisticate technologies and know-how in fabrication and measurement are required to overcome the technological obstacles. KRISS(Korea Research Institute for Standards and Science) is now developing a large scaled mirror fabrication facility and KARI(Korea Aerospace Research Institute) is supporting the development. High precision interferometric test is required during the grinding and polishing of mirror to identify the surface profile precisely. The required fabrication accuracy of the mirror surface profile is $\lambda$/50 ms($\sim$10 nm for visible wave length). Thus the measurement accuracy should be far less than 10 m. To get this requirement, it is necessary to provide vibration free environment for the interferometer system and mirror under test. Thus the vibration responses on the mirror supporting table due to external vibration should be minimized by using a special isolation system. And the responses on the top of the tower, which hold the interferometer during test, should be minimized simultaneously. In this paper, we propose the concept design of vibration suppression system for the KRISS mirror fabrication facility.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
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• pp.411-414
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• 2004

This paper introduces a modulation method for digital wireless communication based on general DS-QPSK. The design and fabrication is for home networking application to a typical RF transmitter with DS-QPSK modulator. This modulator implemented using VHDL hardware programming language, the fabrication of IC chip $5{\times}5 mm^2$ was carried by 27th IDEC MPW(Multi Project Wafer) process in 0.35${\mu}m$ rule at Samsung Inc. This paper presented the important of this technology for the future application in wireless sensor. This module can be efficient usage for home network to transmit the RF wireless sensor system.

• 한국경영과학회지
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• 제28권4호
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• pp.105-114
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• 2003

This paper considers a single facility scheduling problem for the fabrication of components supporting the subsequent assembly into products. Each product consists of two types of components, one is common to all products and the other is unique to itself. The unique components are processed individually and the common components are processed in batches, and a distinct setup is incurred for the production of a batch of common components. Under the so-called “batch availability” environment, we propose an efficient dynamic programming(DP) procedure for the optimal sequencing and batching schedule with minimum total completion times of products in the situation that each product is said to be complete if both common and unique components of the product are finished. Computational results show that the proposed DB procedure is more efficient than the previous work which has considered the same problem as this paper.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.68-71
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• 1989

This paper is to investigate the optimal condition of fabrication for glass-cloth/epoxy composite material. According to the result in this paper, in fabrication of composite materials, the optimal condition of treatment for epoxy silane coupling agent is 1.5% water solution of silane coupling agent by weight. Then, % weight ratio of silane coupling agent VS, glass cloth is about 0.3%. And the optimal post cured condition of glass cloth/epoxy composite material is about 30 hours at 100$^{\circ}C$.

• Steel and Composite Structures
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• 제3권1호
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• pp.13-32
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• 2003

In this paper design and fabrication information system for steel bridge construction is studied and proposed according to the progress of Construction CALS/EC in the construction industry in Japan. The data exchange in this system bases on the text file as well as CAD data with simplified drawings. The concept of this system is discussed following the analysis on the issues of the conventional system. The application of the product model is also discussed including effects and issues on the inspection system. This paper is based on the study carried out by Special Committee on Construction CALS of JASBC to which author belong.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.716-721
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• 2004

Several Solid Freeform Fabrication Systems(SFFS) are commercialized in a few companies for rapid prototyping. However, they have many technical problems including the limitation of applicable materials. A new method of speedy prototyping is required for the recent manufacturing environments of multi-item and small quantity production. The objectives of this paper include the development of a novel method of SFFS, the ${CAFL}^{VM}$(Computer Aided Fabrication of Lamination for Various Material), and the manufacture of the various material samples for the certification of the proposed system and the creation of new application areas. For these objectives, the technologies for a highly accurate robot path control, the optimization of support structure, CAD modeling, adaptive slicing was implemented. In this paper, we design an algorithm that the cutting path of a laser beam which is controlled with constant speed. The laser beam is tangentially controlled in order to solve the inaccuracy of a 3D model surface. The designed algorithm for constant-speed path control and tangent-cutting control is implemented and experimented in the ${CAFL}^{VM}$ system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.311-314
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• 2001

The objectives of this paper include the development of an agile prototype of SFFS, the $CAFL^{VM}$(Computer Aided fabrication of Lamination for Various Material), which is suitable for the multi-item and small-quantity production and various material fabrication. This paper includes remodeling of the layer slices for the 2D cutting, supplementing information of the layer slices and developing process conditions to fabricate products of various shape. And also includes developing control hardware as well as software by enhancing BOF of the manipulator to 3 degree for the precise 2D cutting. It will generate optimal layer trajectory considering the dynamic characteristics of the laser beam. The system can be used as a competitive agile protype system in terms of various materials, fabrication speed, and accuracy by CAD modeling precise layer slicing, material development, robot path control, and optimization of the support structure.