• 한국생산제조학회지
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• 제20권6호
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• pp.761-766
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• 2011

In this study, the optimized design profiles between a seal ring and a seal seat of contacting seal units has been proposed based on the FEM computed results. The maximum temperatures, the thermal distortions in axial and radial directions, and maximum contact normal stresses between a seal ring and a seal seat have been analyzed for various contact sealing profiles. The FEM computed results present that the contact area between seal rings and seal seats is very important for a good tribological performance such as low friction heating, low wear, high contact normal stress in a primary sealing components. The seal surface model III in which has a small sealing contact area shows low dilatation of primary sealing components, and high contact stress between a seal ring and a seal seat. This model with small contact surface of a seal ring produces high friction heating and contact stress. But the model III produces very small deformations of contacting sealing surface because of high convection heat transfer by cooling water circulation around the seal ring surface. Thus, the analysis results recommend a short width of a primary sealing unit rather than a big width of contact surfaces of contacting seal units for reducing a leakage and axial deformation of primary seal components.

• Tribology and Lubricants
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• 제22권3호
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• pp.119-126
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• 2006

In this paper, the contact behavior characteristics of a primary sealing components such as a seal ring and a seal seat has been presented for a small hydro-power turbine. Using the non-linear FEM analysis, the maximum temperature, the axial displacement, radial differences between a seal ring and a seal seat, and maximum contact normal stress have been analyzed for three optimized sealing profiles in which are designed based on the FEM analysis and Taguchi's experimental method. The three primary sealing profiles between a seal ring and a seal seat are strongly related to a leakage of a water for a hydro-power turbine and wear of a primary sealing component. The computed results show that the contact rubbing area between a seal ring and a seal seat is very important for reducing a friction heating and wear in a sealing gap, and increasing a contact normal stress in primary sealing components. Based on the FEM computation, models II and III in which have a small rubbing surface of seal rings show low dilatation of primary sealing components, and high normal contact stress between a seal ring and a seal seat. Thus, the FEM computed results recommend a short contacting width of a primary sealing component for reducing a leakage and thermal distortions, and expanding a seal life. This means that a conventional primary sealing component may be switched to a reduced sealing face of seal rings.

• 제어로봇시스템학회논문지
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• 제22권5호
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• pp.374-381
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• 2016

The sealing technique is widely used for repairing the cracks on the surface of concrete and preventing their expansion in the future. However, it is difficult to ensure the safety of the workers when sealing large structures in inconvenient working environments. This paper presents the development of a sealing robot system to seal various shapes of concrete surface in rough conditions for a long time. If the robot can maintain the desired contact force, the cracks can be completely sealed. An impedance force tracking controller with slope estimator is proposed to calculate the surface slope in real time using the robot position. It predicts the next point in order to prevent the robot from disengaging from the contact surface owing to quick slope changes. The proposed method has been verified by experimental results.

• 대한화학회지
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• 제64권3호
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• pp.153-158
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• 2020

With the recent popularity of mobile devices, the demand for lithium-ion batteries is increasing. In this study, the surface treatment process for the development of the Al (aluminum) lead tab for positive electrode, a key component of the pouch-type lithium-ion battery, was investigated. Anodizing and sealing processes were tested as surface treatment techniques. It was found that only a sealing process is needed to obtain sufficient adhesive strength. In the present study, an adhesive strength of 17 N/12 mm was achieved by degreasing and etching pretreatment, followed by a sealing process of 10 min duration. This adhesive strength was greater than that achievable using Cr (chromium) surface treatment. Using various surface analysis techniques, the shape and composition of the surface before and after being subjected to the surface treatment were compared and analyzed. The results of this study are expected to contribute to the development of an eco-friendly lead tab.

• 한국표면공학회지
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• 제47권6호
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• pp.323-329
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• 2014

Effects of sealant and sealing procedure on corrosion resistance of high velocity oxy-fuel (HVOF) sprayed coatings were studied. HVOF-sprayed CrC-20NiCr coatings were sealed using three commercial sealants based on phenolics and epoxy. Penetration depth of sealants, measured by fluorescent microscope technique, was between $19{\mu}m$ and $340{\mu}m$ depending on sealant, sealing condition or sealing procedure. It was found that sealing on rotation status was more effective than that on stationary specimen due to the Coriolis effect of fluid in pores of the coating. From the CASS results, corrosion resistance of properly sealed CrC-20NiCr coatings was equal to that of hexa-valent chromium plating.

• 제어로봇시스템학회논문지
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• 제22권6호
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• pp.389-396
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• 2016

The sealing robot must be able to calculate the slope of a contact surface for complete adherence of the sealing on different concrete shapes. After the slope is obtained, the robot will track on the surface of the concrete, but this process contains an error in the actual purpose of the force command. The reason this a phenomenon occurs, the non-linearity of the contact surface and the end-effector, is due to parasitic coupling. Errors like make it difficult to measure accurately the respective factors. Therefore, it is regarded as a disturbance that occurs when it follows the work surface it. In this paper, we selected the friction coefficient of the surface as a control factor and designed a compensator to reduce effects of disturbance. Finally, in view of the non-linearity of the end-effector of a robot to contact surfaces directly, we propose a robust force tracking controller in the finite range for managing disturbances that occur during the sealing.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2000년도 추계학술발표회 초록집
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• pp.20-21
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• 2000

• 한국표면공학회지
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• 제52권3호
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• pp.117-122
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• 2019

In this study, surface porosity and corrosion resistance of PEO coatings prepared on the 6061 Al alloy were investigated in terms of sodium phosphate ($Na_3PO_4$) concentrations in an alkaline solution and $NaAlO_2$ sealing. The surface morphologies of the PEO coatings clearly show that the coatings film formed in $9g\;L^{-1}$ had the lowest porosity. The $NaAlO_2$ sealing was found to remove micropores and cracks existing on the surface of PEO coatings. As a result, the $NaAlO_2$ sealing resulted in the movement of corrosion potential toward more positive value and lower corrosion current density.

• Journal of the Korean Wood Science and Technology
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• 제51권6호
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• pp.493-508
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• 2023

Round timber materials of 600 mm length, cut from large-cross-section round timber of red pine (Pinus densiflora S. et Z.) of 450 mm width and 4.2 m length, were prepared as the target of kiln drying in this study. After treating the target materials through end sealing (ES), end sealing - kerfing (ES-K), lateral sealing - end sealing - boring (LS-ES-B), or lateral sealing - partial end sealing (LS-PES), the effects of the treatment on the incidence of drying defects were determined. The target materials with exposed lateral surface and sealed cross surface were steamed at the initial temperature of 65℃ above the official pest control temperature of 56℃, followed by kiln drying toward the final temperature of 75℃. The target materials with sealed lateral surfaces, on the other hand, were dried at the initial temperature of 90℃ at almost the maximum temperature of conventional kiln drying, as there is no risk of early check formation caused by surface moisture evaporation. The final temperature was set at approximately 100℃. The drying time, taken for the target materials with initial moisture content of 70%-80% to reach the target moisture content of 19%, varied across treatment conditions. The measured drying time was 1,146 hours (approximately 48 days) for the timber with sealed cross surface and 745 hours (approximately 31 days) for the timber with sealed lateral surface, until the moisture content reached the target level. The formation of surface checks could not be prevented in the control and ES groups, but a definite preventive effect was obtained for the LS-ES-B and LS-PES groups.

• 대한토목학회논문집
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• 제35권2호
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• pp.481-491
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• 2015

콘크리트 표면에 발생된 균열은 구조물의 수명에 영향을 미치는 주요원인으로 작용하기 때문에 주기적인 검사와 유지관리가 필요하다. 콘크리트 표면 유지관리를 위한 실링작업은 표면에 발생된 균열을 초기에 보수하는 방법으로 시간 경과에 따른 균열의 추가생성 및 확산을 방지하는데 효과적이다. 하지만, 교량 하부의 실링작업은 열악한 작업환경으로 인하여 작업자들의 안전성 확보에 문제가 있다. 이런 이유로, 콘크리트 구조물의 유지관리를 위한 실링자동화의 필요성이 부각되고 있다. 본 논문은 콘크리트 교량 하부에 발생된 균열의 실링작업에 로봇을 적용하기 위한 두 가지 제어방법에 대하여 제안한다. 하나는, 균열의 궤적을 자동으로 추적하는 방법이다. 로봇은 카메라로부터 취득되는 영상정보로 균열의 궤적을 파악하는데, 이전 시점의 궤적 정보를 통하여 다음 이동할 시점의 정보를 유추할 수 있다면, 실시간으로 변동되는 궤적 정보에 대응이 가능하면서 자동으로 균열을 추적할 수 있다. 다른 하나는 접촉면에 일정한 힘을 유지하여 실링하는 방법이다. 장기간 외부 환경에 노출된 거친 표면에서도 로봇이 일정한 접촉력을 유지하며 실링작업을 수행한다면, 균등한 완성도를 유지할 수 있다. 이러한 균일한 힘의 유지를 위하여 임피던스를 이용한 힘 제어 기법을 제안한다. 본 논문에서는 실링 로봇에 적용하기 위하여 개발한 두 가지 제어기법들을 소개하고, 그것을 적용한 Lab Test와 Field Test를 수행한다. 이 시험결과를 토대로 로봇의 현장적용에 대한 의견을 제시한다.