• Title/Summary/Keyword: 최적연마시간

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Bending Strength Properties of SiC Ceramics at Different Roughness Values of Polishing Plates (연마판의 거칠기에 따르는 SiC 세라믹스의 굽힘강도 특성)

  • Nam, Ki-Woo;Kim, Eun-Sun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.7
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    • pp.779-784
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    • 2011
  • This study was carried out on the crack healing of three types of SiC ceramics based on a $SiO_2$ additive, taking into account the roughness of the polishing plate used for polishing the specimens. The mixtures were subsequently hot-pressed in $N_2$ gas for one hour under 35 MPa at 2053 K. In these specimens, the optimized crack-healing condition was 1373 K for one hour in air. The crack-healing material of the cracked part was the glassy phase of $SiO_2$ that was formed by the oxidation of SiC. In the optimum healing condition, the bending strength of non-polished SiC ceramics was not completely recovered. However, the bending strength of the SAY specimen was excellent, considering the economic aspects of SAY, SAYS-1, and SAYS-2. The SAY specimen is definitely superior to the others after an hour of heat treatment. There was a decrease in the number and size of defects in the specimen polished by using a $125-{\mu}m$ polishing plate; however, the micro-surface defects were not completely repaired. The specimen polished by using a 40-${\mu}m$ polishing plate showed little voids or surface defects after an hour of heat treatment. The bending strength of the specimen mirror-polished by using a 6-${\mu}m$ polishing plate was completely recovered.

A Study on Mirror Surface Manufacturing Process for Solar Cell (태양전지용 경면 제조 공정에 대한 연구)

  • 이종권;박지환;송태환;류근걸;이윤배
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.4 no.1
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    • pp.47-49
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    • 2003
  • The cost of material and slicing of silicon wafer occupied more than 30% of solar cell manufacturing cost. The substitution of silicon wafer into STS 304 stainless steel could be the promising solution to decrease the material cost. Moreover the stainless steel solar cell could have the advantage of low weight and durability. However, the highly polished surface is required to meet the characteristic of solar cell. The electropolishing process in phosphoric acid based solution was used to get the surface quality. The obtained result was 28 nm obtained in current density of 2Amfi/$cm^2$ at $80^{\circ}C$. The leveller effect of glycerine, ethylene glycol and propylen glycol was studied. When the 0.4 g/l of ethylene glycol was added to the electrolyte, the surface roughness was best, 15 nm.

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Process Optimization for Reduction of Waste Acids of Electropolishing Solution using Round Bus Bar (구형 부스바를 이용한 전해연마액의 폐산 폐기물 감소를 위한 공정 최적화)

  • Kim, Soo Han;Cho, Jaehoon;Park, Chulhwan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.8
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    • pp.722-727
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    • 2016
  • In this study, we attempted to reduce the generation of waste acids in the electropolishing process by improving the current efficiency. The optimum conditions of the electropolishing process when using the round bus bar were determined by the Taguchi method. The current density, polishing time, electrolyte temperature and flow rate were selected as the control factors for the current efficiency in the electropolishing process. An orthogonal array was created by considering three levels for each factor and experiments were carried out. The larger-the-better SN ratios were calculated by the Taguchi method. The current density was the most important factor affecting the current efficiency and the polishing time was the least important one. The optimum conditions to minimize the generation of waste acids were a current density of $45A/dm^2$, polishing time of 4 min, electrolyte temperature of $65^{\circ}C$ and flow rate of 7 L/min. The results of the ANOVA confirmed that the effects of the current density, electrolyte temperature and flow rate are significant at the 95% confidence level. The increase in the contact area and contact force afforded by using the round bus bar improved the current efficiency which, in turn, reduced the amount of waste acids generated. Further research is planned to investigate the effect of the type of bus bar on the current efficiency.

Effect of Mixed Abrasive Slurry (MAS) on the Tetra-Ethyl Ortho-Silicate (TEOS) Film (혼합 연마제가 TEOS 막에 미치는 영향)

  • Lee, Young-Kyun;Han, Sang-Jun;Park, Sung-Woo;Seo, Yong-Jin;Lee, Woo-Sun
    • 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.

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Determination of Efficient Superfinishing Conditions for Mirror Surface Finishing of Stainless Steel (스테인레스 강의 경면가공을 위한 효율적 수퍼피니싱 조건의 결정)

  • Kim, Sang-Kyu;Cho, Young-Tae;Jung, Yoon-Gyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.2
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    • pp.100-106
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    • 2013
  • Stainless steel has some excellent properties as the material for the mechanical component. Purpose of this study is carried out to obtain mirror surface on the surperfinishing of stainless steel with high efficiency. To achieve this, we have conducted a series of polishing experiment for stainless steel using abrasive film from the perspective of oscillation speed, the rotational speed of workpiece, contact roller hardness, contact pressure and feed rate. Abrasive film used this study is a micro-finishing film and a lapping film. Furthermore, the polishing characteristics and efficiency of stainless steel is discussed through measuring optimal polishing time and surface roughness. From the obtained results, it was confirmed that efficient superfinishing conditions and polishing characteristic of Stainless steel can be determined.

Determination of Efficient Superfinishing Conditions for Mirror Surface Finishing of Engineering Ceramics (엔지니어링 세라믹스의 경면연마를 위한 효율적인 슈퍼피니싱 조건의 결정)

  • Kim, Sang-Kyu;Cho, Young-Tae;Jung, Yoon-Gyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.5
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    • pp.76-81
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    • 2014
  • The Engineering ceramics have some excellent properties as materials for modern mechanical and electrical components. It is, however, not easy to polish them efficiently because they are strong and hard. This study is carried out to obtain a mirror surface on engineering ceramics by surperfinishing with high efficiency. To achieve this, we conducted a series of polishing experiments using representative engineering ceramics, such as $Al_2O_3$, SiC, $Si_3N_4$ and $ZrO_2$, using diamond abrasive film from the perspective of oscillations peed, the rotational speed of the workpiece, contact roller hardness, contact pressure and feed rate. Furthermore, the polishing efficiency and characteristics for engineering ceramics are discussed on the basis of optimal polishing time and surface roughness. Our results confirmed that efficient superfinishing conditions and polishing characteristics of engineering ceramics can be determined.

고속가공 가공특성의 실험계획법에 의한 효율적인 지식기반 DB 구축에 관한 연구

  • 원종률;남성호;이석우;최헌종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.05a
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    • pp.322-322
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    • 2004
  • 최근 기계가공은 제품생산의 리드타임(lead time)의 단축 및 가공시간 단축을 통하여 비용을 절감하고 생산성을 극대화하는데 초점이 맞춰지고 있다. 고속가공(HSM: high-speed machining)은 별도의 연마 공정 없이 그 자체로 고품위, 고정도의 가공물을 생성하여 공정을 축소시키며, 가공시간을 단축시켜 생산성을 향상시킬 수 있다. 이러한 고속가공에 있어서 가공특성은 공작기계의 특성, 공구 및 가공조건뿐만 아니라 제품 형상 등의 다양한 요인에 의해 결정되어진다.(중략)

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A Experimental Study on Efficient Applicable Combination of Super Finishing Films for Mirror Surface Machining (경면가공을 위한 수퍼피니싱필름의 효율적인 적용조합에 관한 실험적 연구)

  • Cho, Kang-Su;Kim, Sang-Kyu;Cho, Young-Tae;Jung, Yoon-Gyo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.1
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    • pp.121-128
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    • 2014
  • Superfinishing is essential for mirror surfaces, because among mechanical components cylindrical workpieces such as spindles must maintain precision and reliability with respect to functional characteristics. However, research on standardization of polishing film application combination to obtain mirror surfaces is insufficient. Consequently, this has been a factor in rising costs of mechanical components. Therefore, in this study, experiments have been conducted to determine efficient polishing film application combination for mirror surfaces ranging from ductile materials such as SM45C, brass, aluminium 7075, and titanium to brittle materials such as $Al_20_3$, SiC, $Si_3N_4$, and $ZrO_2$. From the experimental results, efficient polishing film application combination for metallic materials and ceramic materials is confirmed.

An Optical Surfacing Technique of the Best-fitted Spherical Surface of the Large Optics Mirror with Ultra Precision Polishing Machine (대형 광학계 연마 장비에 의한 대구경 반사경의 최적 근사 구면 제조 방법에 관한 연구)

  • Song, Chang Kyu;Khim, Gyungho;Hwang, Jooho;Kim, Byung Sub;Park, Chun Hong;Lee, Hocheol
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.3
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    • pp.324-330
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    • 2013
  • This paper describes a novel method to surface large optics mirror with an extremely high hardness, which could replace the high cost of the repetitive off-line measurement steps and the large ultra-precision grinding machine with ultra-positioning control of 10 nm resolution. A lot of diamond pellet to be attached on the convex aluminum base consists of a grinding tool for the concave large mirror, and the tool was pressured down on the large mirror blank. The tool motion at an interval on the spiral path was controlled with each feed rate as the dwell time in the conventional computer-controlled polishing. The shape to be surfaced was measured directly by a touch probe on the machine without any separation of the mirror blank. Total 40 iterative steps of the surfacing and measurement could demonstrate the form error of RMS $7.8{\mu}m$, surface roughness of Ra $0.2{\mu}m$ for the mirror blank with diameter of 1 m and spherical radius of curvature of 5400 mm.

역세척을 이용한 함유 세척수의 한외 여과 특성

  • 김종표;김재진;정건용;전성덕;민병렬
    • Proceedings of the Membrane Society of Korea Conference
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    • 1997.04b
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    • pp.43-44
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    • 1997
  • 세척제는 금속 표면에 도포되어 있는 왁스, 그리스, 방청유 등의 윤활유 및 금속 가공 중에 사용한 절삭유, 연마유 등의 유지성 물질을 제거하는 탈지 효과와 표면에 묻어 있는 오물을 제거하는 목적으로 우수한 세정력을 지니고 있다. 세척제는 현장의 세척조의 상태가 가동 시간이 길어짐에 따라 유분이 과포화하게 되고 한정된 계면활성제량 때문에 미처 Micelle을 형성하지 못한 광유중 일부는 에멀젼 내 Oil Drop 형태로 존재하고 나머지는 에멀젼층 위에 부유하게 된다. 따라서 세척제의 세정력을 유지하기 위하여는 주기적으로 세척액중의 유분을 제거하여야 한다. 본 연구에서는 한외여과막을 이용하여 세척수 중 존재하는 Oil 성분을 제거함으로써 세척수의 수명을 극대화시키고자 한다. 또한 한외여과시 동반되는 농도 분극화 현상을 줄이고 투과특성을 향상시키기 위하여 압축질소로 주기적으로 역세척하며 최적운전 조건을 확인하는데 있다.

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