• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.259-259
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• 2004

정밀부품의 가공 시에 발생되는 burr는 제품의 정밀도, 성능과 제품의 생산성에도 부정적인 영향을 끼치다. 따라서 효율적인 burr의 제거는 제품의 성능의 향상뿐만 아니라 생산성의 향상에도 긍정적인 영향을 미칠 수 있다. 자기 연마법(Magnetic Abrasive Finishing)은 연마제의 연마특성과 철의 자기화 성질을 이용한다. 자기장내의 자기력선의 응집현상을 통해서 burr를 제거하는 방법이다. 자기 유도자에 의해 형성된 magnet flow를 따라 지립이 정렬을 하고 정렬된 지립은 브러쉬의 역할을 하여 burr를 제거하게 된다.(중략)

• Journal of IKEEE
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• v.23 no.4
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• pp.1175-1181
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• 2019

In this paper, we have studied the chemical mechanical polishing(CMP) characteristics of mixed abrasive silica slurry(MAS) retreated by adding of manganese oxide(MnO₂) abrasives within 1:10 diluted silica slurry. A slurry designed for optimal performance should produce high removal rates, acceptable polishing selectivity with respect to the underlying layer, low surface defects after polishing, and good slurry stability. The polishing performances of MnO₂ abrasive-added MAS are evaluated with respect to their particle size distribution, surface morphology, and CMP performances such as removal rate and non-uniformity. As an experimental result, we obtained the comparable slurry characteristics compared to original silica slurry in the view-point of high removal rate and low non-uniformity. Therefore, our proposed MnO₂-MAS can be useful to save on the high cost of slurry consumption since we used a 1:10 diluted silica slurry.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.2
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• pp.141-151
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• 2015

A new rock excavation method using an abrasive injection waterjet system has been developed to enhance the efficiency and reduce the vibration of tunnel excavation. The abrasive feed rate is an important factor for the cutting performance and the economical efficiency of waterjet-based excavation. In this study, various experiments were performed to explore the effects of major process parameters for both the abrasive feed rate and the suction pressure occurring inside the mixing chamber when the abrasives are inhaled. Experimental results reveal that the abrasive feed rate is affected by geometry parameters (abrasive pipe height, length, and tortuosity), abrasive parameters (abrasive particle size), and jet energy parameters (water pressure and water flow rate). In addition, the relation between the cutting performance and the abrasive feed rate was discussed on the basis of the results of an experimental study. The cutting performance can be maximized when the abrasive feed rate is controlled appropriately via careful management of major process parameters.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.353-358
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• 2009

The ability of natural abrasives which were recovered from CRT glass polishing process was evaluated. Comparing the center line average roughness values of a glass polished with new pumice (Ra = $0.039{\mu}m$) and with new garnet (Ra = $0.031{\mu}m$), the glass surface polished with the recycled pumice and the garnet had less pits on the surface with smaller Ra values (Ra = $0.025{\mu}m$ for recycled pumice and Ra = 0.029 for recycled garnet). Recycled rouge contains amorphous glass fragments so that it should be used as a cement replacement rather than recycle into an abrasive. Nnatural abrasives, pumice and garnet powder, which are used in CRT glass polishing process can be recycled into abrasives so that it can help to minimize costs and environmental impact from the production of abrasives and the disposal of waste sludge.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.763-778
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• 2019

Abrasive waterjet cutting technology has been used for rock excavation of tunnels and underground structures due to various advantages. In order to cut rocks by using the abrasive waterjet system, abrasive is essential to enhance impact energies for fracturing the target rock. Since garnet abrasives are not produced in Korea, alternative abrasives, instead of garnets, are needed to achieve the economical waterjet cutting. This study is to analyze cutting performance for rocks with sandy particles as alternative abrasive. Cutting tests were carried out on granite specimens at the constant waterjet energy (e.g., water pressure or water flow rate). The five kinds of sands, sampled by construction fields and natural sites, were prepared to perform the experimental tests. When sea sand was used as an alternative abrasive, cutting performance was secured to be 60~70% compared to the commercial garnet abrasive. Thus, it is expected that sand abrasives can be applied on the waterjet cutting process for the economical excavation construction.

• Analytical Science and Technology
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• v.19 no.5
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• pp.394-399
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• 2006

The polishing performance and the relationships of electrochemistry depending upon oxidizers and additives in the tungsten CMP slurry used in semiconductor industry were investigated. Hydrogen peroxide, ferric nitrate and potassium iodate were used as oxidizers and they showed different oxidation reactions on tungsten film depending on the kind of oxidizers and pH of slurry. The differences influenced the polishing performance. Etching reaction was predominated in the hydrogen peroxide. However, passivation reaction was prevailed in ferric nitrate and potassium iodate. TMAH and KOH raised the potential energy and removal rate of tungsten, and improved a dispersion characteristic of slurry by increasing absolute value of zeta potential. Addition of 100 ppm of poly(acrylic acid) of M.W. 250,000 improved dispersion ability.

• Tunnel and Underground Space
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• v.8 no.4
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• pp.332-341
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• 1998

Conventional polishing of stone panel edges has been done by hand. While this has changed somewhat with the advent of automatic machines, it is still very much a hand finishing technology. For the development of edge shape milling tool, the primary test on characteristics of edge shape milling tool was carried out. This paper presents the results of tests focused upon the milling capability that was varied by the variables of operation parameters. Author tried to confirm the effect of six operation parameters of equipment such as rotation speed, advance speed, applied load, water flow rate and rotational direction. The result from test was described in term of shape milling capability that was defined as cutting volume of rock by unit weight of tool wear. The variance of the results could indicate the optimum level of each operating parameters. The test was also carried out to determine the abrasion resistance varied according to the abrasive flow rate. The abrasion resistance was increased with the abrasive flow rate, but over some rate it was not changed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.541-541
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• 2008

반도체 소자가 차세대 초미세 공정 기술 도입의 가속화를 통해 고속화 및 고집적화 되어 감에 따라 나노(Nano) 크기의 회로 선폭 미세화를 극복하고자 최적의 CMP (Chemical Mechanical Polishing) 공정이 요구되어지고 있다. 이처럼 CMP 공정이 반도체 제조 공정에 적용됨으로써 공정 마진 확보에 진일보 하였으나 CMP 장비의 공정 조건, 슬러리의 종류, 연마패드의 종류 등에 의해 CMP 성능이 결정된다. 특히 슬러리는 연마 공정의 성능에 중요한 영향을 미치는 요인이다. 고가의 슬러리가 차지하는 비중이 40% 이상을 넘고 있어 슬러리 원액의 소모량을 줄이기 위한 연구들이 현재 활발히 진행되고 있다. 본 연구에서는 새로운 연마제의 특성을 알아보기 위해 탈이온수(De-ionized water; DIW) 에 $CeO_2$, 연마제를 첨가한 후 분산시간에 따른 연마 특성과 AFM, EDX, XRD, TEM분석을 통해 그 가능성을 알아보았다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.149-149
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• 2004

반도체 산업이 급속하게 발전함에 따라 고집적, 대용량이 요구되고 있으며, 이에 따라 선폭의 미세화, 웨이퍼 크기의 증가, 패턴의 다층화가 필수적인 조건으로 대두되고 있다. 이러한 요구를 만족시키기 위해서는 고정도의 표면상태와 칩과 웨이퍼 전면에서의 균일한 가공이 필요하다. 따라서 화학 기계적 연마를 통한 안정하고 고성능의 평탄화는 고집적 소자형성에 있어서 핵심 기술이 되고 있다.(중략)

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1525-1530
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• 2014

In this research, we describe teaching based sweeping control for grinder robot has been proposed as a system which is suitable to work utilizing pressure sensitive alternative to human. Teaching method is used for grinder robots operations because of their position accuracy, path accuracy, and machining reaction force. A grinder robot for two-dimensional iron plate was developed on the basis of an force sensor based teaching method. An automatic-path-generation method and experimental results using specific points was adopted to reduce the number of teaching points and time. And also, in order to determine the proper machining conditions, various machining conditions such as grinder-wheel rotation speed and robot moving speed, were evaluated.