• 한국기계가공학회지
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• 제15권2호
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• pp.72-77
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• 2016

Airplane reservoirs made of Al7075 are coated with an anodizing layer to maintain precision, air tightness and corrosion resistance. It is commonly required that the inner surface roughness of the reservoir be less than an average $0.2{\mu}m$ to maintain stable oil pressure. Even though precision polishing is necessary to achieve this quality it is not easy. Inner surface roughness is not uniform and the quality of the product is irregular because most of the work is done by hand. The purpose of this study is to design an exclusive polishing machine and to determine the standard cutting condition and polishing condition necessary for good inner surface roughness and to improve workefficiency.

• 한국표면공학회지
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• 제55권4호
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• pp.236-246
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• 2022

Electropolishing is a surface finishing treatment that compensates for the disadvantages of the mechanical polishing process. It not only has a smooth surface, but also improves corrosion resistance. Therefore, the purpose of this investigation is to examine the corrosion resistance and electrochemical characteristics in seawater of UNS S31603 with electropolishing process time. The roughness improvement rate after electropolishing was improved by about 78% compared to before polishing, indicating that the electropolishing is effective. As a result of potential measuring of mechanical polishing and electropolishing, the potential of electropolishing was nobler than the mechanical polishing condition. As a result of calculating the corrosion current density after potentiodynamic polarization experiment with electropolishing conditions, the corrosion current density of mechanical polishing was about 6.4 times higher than that of electropolishing. After potentiodynamic polarization experiment with electropolishing conditions, the maximum damage depth of mechanical polishing was about 2.2 times higher than that of electropolishing(7 minutes). In addition, the charge transfer resistance of the specimen electropolished for 7 minutes was the highest, indicating improved corrosion resistance.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.20-23
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• 2004

As the integrated circuit device shrinks to the smaller dimension, the chemical mechanical polishing(CMP) process was required for the global planarization of inter-metal dielectric(IMD) layer with free-defect. However, as the IMD layer gets thinner, micro-scratches are becoming as major defects. Chemical-Mechanical polishing(CMP) of conductors is a key process in Damascene patterning of advanced interconnect structure. The effect of alternative commercial slurries pads, and post-CMP cleaning alternatives are discuss, with removal rate, scratch dentisty, surface roughness, dishing, erosion and particulate density used as performance metrics. Electroplated copper deposition is a mature process from a historical point of view, but a very young process from a CMP perspective. While copper electro deposition has been used and studied for decades, its application to Cu damascene wafer processing is only now gaining complete acceptance in the semiconductor industry. The polishing mechanism of Cu-CMP process has been reported as the repeated process of passive layer formation by oxidizer and abrasion action by slurry abrasives. however it is important to understand the effect of oxidizer on copper passivation layer in order to obtain higher removal rate and non-uniformity during Cu-CMP process. In this paper, we investigated the effects of oxidizer on Cu-CMP process regarding the additional volume of oxidizer.

• 한국공작기계학회논문집
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• 제14권2호
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• pp.14-20
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• 2005

This paper describes a dwell time calculation algorithm for polishing tool path generation in the small toot polishing process of the axis-symmetrical lens. Generally dwell time control in the polishing machines means that small polishing tool stays for a dwell time at the specific surface position to get the expected polishing depth. Polishing depth distribution on an aspherical lens surface consists of the superposition of the local polishing depth at the each dwell position. Therefore, tool path generation needs each dwell time together with tool positioning data during the polishing tool movements on the aspherical lens surface. The linear algebraic equation of removal depth removal matrix and dwell time is formulated. Parametric effects such as the dwell d interval are simulated to validate the dwell time calculation algorithm.

• 한국정밀공학회지
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• 제20권3호
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• pp.42-49
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• 2003

In this paper, we provide the results of polishing temperature distribution by way of infrared ray measurement system as well as polishing resistance, which can be interpreted as tribological aspects of CMP, using force measurement system. The results include the trend of polishing temperature, its distribution profile and temperature change during polishing. The results indicate that temperature affects greatly to the removal rate. Polishing temperature increases gradually and reaches steady state temperature and the period of temperature change occurs first tens of seconds. Furthermore, the friction force also varies as the same pattern with polishing temperature from high friction to low. These results suggest that the first period of the whole polishing time greatly affects the nonuniformity of removal rate.

• 한국정밀공학회지
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• 제14권10호
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• pp.58-67
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• 1997

Generally, die polishing process occupies about 30 .approx. 50% of the whole die manufacturing time. However, die polshing has not been automated yet, since it needs a great deal of experience and skill. This study aims at development of an expert system for die polishing which gives such optimal parameters as tool and polishing conditions. Through experiments, polishing characteristics such as surface roughness, stock removal and scratch were analyzed quantitatively for each polishing tool, and a knowledge base for the expert system was established. Evaluation tests show that the developed system works well to suggest the optimal polishing conditions and it is very promising.

• 한국기계가공학회지
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• 제19권8호
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• pp.110-116
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• 2020

Aircraft hydraulic oil reservoirs made with aluminum 7075 have an anodized coating to enable airtightness and corrosion resistance. To maintain a stable oil pressure, the internal surface roughness of the reservoir should be less than approximately 0.2 ㎛. To this end, precision polishing must be performed. However, ensuring the processing quality is challenging, as most polishing operations are performed manually, owing to which, the inner surface roughness is not uniform, and the product quality is irregular. Therefore, we developed a special superfinishing machine to realize the efficient inner polishing of an aircraft hydraulic oil reservoir, by using an abrasive film to improve the process throughput and uniformity. In the experiment involving the superfinishing of an anodized aluminum 7075 cylinder specimen by using the proposed machine, a higher surface roughness than that achieved in the repetitive manual polishing process could be realized.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.569-570
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• 2006

The conditioning process is very important process for the CMP (Chemical Mechaning Polishing). This process regenerates the roughness of the polishing pad during the CMP process, increases the MRR (Material Removal Rate) and gives us longer pad life so conditioning process is essential for the CMP, and conditioning process influences the polishing pad shape gradually. Conditining process is related to the Non-Uniformity. In This paper, Kinematic of the conditioning process and mathematic modeling of the pad wear is studied and result shows how the various parameters influence the pad shape and WIWNU[1]. Consequently through these parameter, optimal design of the conditioning process equipment is predicted.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.1807-1812
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• 2014

플라스틱은 형상의 구애를 거의 받지 않아 자유 곡면형상을 표현할 수 있고, 다양한 색상과 저렴한 가격으로 대량으로 생산할 수 있는 장점을 가지고 있으며, 차량의 경량화 부품소재로 많이 사용되고 있는 가운데 자동차 도어필러 성형은 엔지니어링 플라스틱을 사용하는 대표적인 예로서, 사출성형으로 생산되고 있다. 이러한 방법으로 생산된 부품은 대부분 외관 부품으로 사용되어 표면에 대한 불량 제거가 무엇보다 중요하며, 이를 위해 마지막 공정으로 폴리싱 작업을 수행하고 있다. 작업자에 의해 이루어지는 폴리싱 작업은 많은 힘을 요구하며, 이로 인해 작업자들의 피로도가 높은 공정으로 분류되어 기피공정이 되고 있다. 본 연구에서는 영상처리를 이용하여 폴리싱 공정의 작업을 작업자와 연계하여 불량위치를 검출하고 폴리싱 공정을 자동으로 수행할 수 있도록 폴리싱 자동화 장비의 개발하였다. 이를 통해 생산시간 단축(30초)및 작업인원 1명 감소로 생산단가의 경쟁력을 높이는 개선효과를 기대하게 되었다.

• 한국기계가공학회지
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• 제13권1호
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• pp.92-99
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• 2014

An aspherical lens, which resolves several problems with a spherical lens,typically serves asa key part of an optical system. Generally, an aspherical lens is fabricated using a diamond turning machine or by mean of injection molding. However, residual stress and/or tool marks can arise when using a commercial fabricating method such as DTM or injection molding. A polishing process, thus, is commonly used to obtain a high-precision aspherical lens. In this study, a polishing method using MR fluid was applied to minimize several problems, in this case residual stress and the creation of tool marks, during the cutting process. The MR polishing system was developed to polish aspherical lenses. A series of experiments were performed to obtain a very fine surface roughness. PMMA (the lens material for molding) was used as a workpiece, and the gap size, magnetic field intensity, wheel speed and feed rate were selected as the parameters in this study. Finally, a very fine surface roughness of Ra=2.12nm was obtained after MR polishing.