• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.427-430
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• 2005

Improving the productivity of steel cord is required due to the increase in demand for it, even though steel cord being used as a reinforcement of a tire has been produced at multi-pass wet wire drawing process over 1000m/min. To improve the productivity, if just increase drawing speed, it causes temperature rise, fracture arisen by embrittlement during drawing process. To increase drawing speed affecting productivity, the variation of wire temperature during multi-pass wet wire drawing process is investigated in this study. In result, the multi-pass wet wire drawing process is redesigned. The redesigned wet drawing process with 27 passes efficiently controls wire temperature during drawing process. It, therefore, enables drawing process to be possible at ultra high speed with 2000m/min. It becomes possible to improve the productivity of steel cord in this paper because the increase in drawing speed could be achieved.

• 한국정밀공학회지
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• 제27권1호
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• pp.11-17
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• 2010

This study investigates the non-traditional manufacturing process of dry wire electrical discharge machining (EDM) in which liquid dielectric is replaced by a gaseous medium. Wire EDM experiments of thin workpieces were conducted both in wet and dry EDM conditions to examine the effects of spark cycle (T), spark on-time ($T_{on}$), thickness of work pieces, and work material on machining performance. The material removal rate (MRR) in the dry wire EDM case was much lower than that in the wet wire EDM case. In addition, the thickness of workpiece and work-material were found to be critical factors influencing the MRR for dry EDM process. The relative ratios of spark, arc and short circuit were also calculated and compared to examine the effectiveness of processes of dry and wet wire EDM.

• 한국정밀공학회지
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• 제21권4호
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• pp.32-38
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• 2004

Laser-induced thermochemical wet etching of titanium in phosphoric acid has been investigated to examine the feasibility of this method fur fabrication of microstructures. Cutting, drilling, and milling of titanium foil were carried out while examining the influence of process parameters on etch width, etch depth, and edge straightness. Laser power, scanning speed of workpiece, and etchant concentration were chosen as major process parameters influencing on temperature distribution and reaction rate. Etch width increased almost linearly with laser power showing little dependence on scanning speed while etch depth showed wide variation with both laser power and scanning speed. A well-defined etch profile with good surface quality was obtained at high concentration condition. Fabrication of a hole, micro cantilever beam, and rectangular slot with dimension of tess than 100${\mu}{\textrm}{m}$ has been demonstrated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.935-938
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• 1997

Recently, the minimum line width shows a tendency to decrease and the multi-level increase in semiconductor. Therefore, a planarization technique is needed and chemical mechanical polishing(CMP) is considered as one of the most suitable process. CMP accomplishes a high polishing performance and a global planarization of high quality. But there are several defects in CMP such as micro-scratches, abrasive contaminations, and non-uniformity of polished wafer edges. Wet etching include of Spin-etching can improve he defects of CMP. It uses abrasive-free chemical solution instead of slurry. On this study, ILD(INterlayer-Dielectric) was removed by CMP and wet-etching methods in order to investigate the superiority of wet etching mechanism. In the thin film wafer, the results were evaluated at a viewpoint of material removal rate(MRR) and within wafer non-uniformity(WIWNU). And pattern step height was also compared for planarization characteristics of the patterned wafer.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2011년도 추계학술논문발표회 논문집
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• pp.61-66
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• 2011

부압식 스프링클러 설비는 우리나라에서 일반적으로 사용되고 있는 준비작동식이나 건식 또는 습식 스프링클러 설비의 2차측 배관내의 압력을 부압(진공)상태로 유지시켜 오작동(스프링클러 헤드의 파손 또는 배관의 누수) 시에 발생되는 소화수의 누수를 진공압(-0.05~-0.08MPa)으로 흡입하는 구조로 설계되어 수손피해에 대한 위험도를 제거 하여 기존의 스프링클러 시스템의 문제점을 해결 할 수 있는 획기적인 기술로 볼 수 있다. 또한 부압식 스프링클러 설비는 습식, 준비작동식에 해당하는 시설에 모두 적용이 가능하며 매년 국내, 외에서 건설되는 모든 대상물에도 설치가 가능하며 기존 설비된 건물에도 손쉽게 적용이 가능하여 앞으로 IT관련 산업, 반도체 제조공장, 호텔, 학교, 병원, 관공서, 지하철 역사, 정밀가공 제조설비 등 특히 내진설계에 적용되고 있는바 그 적용성이 무궁무진한바 본 부압식 스프링클러 시스템의 연구를 통한 확대에 대한 가능성은 무한할 것으로 예상된다.

• 한국정밀공학회지
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• 제31권1호
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• pp.75-81
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• 2014

Laser beam machining has been known as efficient for glass micromachining. It is usually used the ultra-short pulsed laser which is time-consuming and uneconomic process. In order to use economic and powerful long pulsed laser, indirect processing called laser-induced backside wet etching (LIBWE) is good alternative method. In this paper, micromachining of glass using Nd:YAG laser with nanosecond pulsed beam has been attempted. In order to improve shape accuracy, combined processing with magnetic stirrer has been widely used. Magnetic stirrer acts to circulate the solution and remove the bubble but it is not suitable for deep hole machining. To get better effect, ultrasonic vibration was applied for improving shape accuracy.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.245-249
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• 2004

Transparent materials such as fused silica are important materials in optical and optoelectronics field because of its outstanding properties, such as transparency in a wide wavelength range, strong damage resistance for laser irradiation, and high thermal and chemical stability. However, these properties make it difficult to micromachine silica in micro-sized quantities. In this study, we fabricated a micro patterns on the surface of fused silica plate using laser induced wet etching. KrF excimer laser was used as a light source. There were no burrs and micro cracks on the etched surface of fused silica and the flatness of the etched surface was fairly good. We investigated the influence of etchant upon the etch rate and quality in laser induced wet etching. Pyrene-acetone, toluene, and pyrene-toluene solution were used as etchant. In the side of etch rate, toluene and pyrene-toluene solution were better than pyrene-acetone solution.

• 한국기계가공학회지
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• 제3권4호
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• pp.29-36
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• 2004

An experimental study on drilling of stainless steel is conducted using TiAlN coated drills and HSS twist drills with several cutting conditions; feed rate, spindle rotational speed, and dry/wet cutting. The effects of number of hole on the thrust force are examined by cutting force measurement. The flank wear of the drills and the change of hole diameter are quantitatively observed using a vision system. It is found that the thrust force in drilling with TiAlN coated drills decrease under dry and wet machining, whereas the flank wear resistance is improved.

• 소성∙가공
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• 제11권7호
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• pp.601-607
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• 2002

Optically transparent materials such as fused silica, quartz and crystal have become important in the filed of optics and optoelectronics. Laser ablation continues to grow as an important technique for micromachining and surface modification of various materials, because many problems caused by direct contact between tools and workpiece can be avoided. Especially, laser ablation with excimer lasers enables fine micromachining of transparent materials such as fused silica, quartz and crystal, etc. In this study, laser-induced wet etching of fused silica in organic solution was conducted. KrF excimer laser was used as a light source and acetone solution of pyrene was used as etchant. Changing the number of laser pulses, micro holes of various depths are fabricated.

• 한국식품조리과학회지
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• 제22권2호
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• pp.147-157
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• 2006

멥쌀가루의 특성을 개선하여 제빵을 비롯한 가공 적성을 증가하기 위해 습식제분쌀가루를 이용하여 수분함량을 30%와 50%로 조절하고, 50과 $70^{\circ}C$로 6시간과 18시간 열처리하여 수분-열처리 쌀가루를 제조하였다. 제조한 수분-열처리 쌀가루의 특성인 입도분포, 형태적, 이화학적특성과 호화특성을 건식제분과 습식제분 쌀가루와 비교하였다. 30% 수분함량으로 처리한 쌀가루입자는 습식제분쌀가루와 같이 $4-20{\mu}m$와 $100-200{\mu}m$ 범위에 분포하였으며 열처리온도가 증가하면 $200{\mu}m$이상의 입자가 형성되었다. 주사전자현미경으로 형태를 보면 30% 수분으로 처리한 경우에는 전분입자를 뚜렷하게 볼 수 있었으나 50%로 처리한 쌀가루는 쌀가루 입자끼리 엉겨 붙거나 호화된 상태를 보여주었다. 색도는 수분함량과 열처리온도가 높은 경우 명도는 감소하고 황색도는 증가하였으며 30% 수분함량으로 처리한 쌀가루의 물결합능력은 SWRF와 비슷하였다. $70^{\circ}C$에서 쌀가루의 팽윤력은 수분함량에 따른 차이는 없었으며 같은 수분함량에서 열처리 온도가 낮은 $50^{\circ}C$일 때 더 높았고 용해도는 더 낮았다. 신속점도 측정기에 의한 호화개시온도는 수분-열처리로 모두 높아졌으며 최고점도는 30%로 처리한 쌀가루가 높았고 setback은 30%로 $50^{\circ}C$에서 처리하였을 때 낮아 노화에 안정성을 보였다. 그러므로 수분함량을 30%로 조절하고 호화온도 이하의 온도인 $50^{\circ}C$로 처리한 수분-열처리 쌀가루의 특성이 쌀가루의 가공용으로 습식제분쌀가루보다 개선된 것으로 생각되었다.