• Title/Summary/Keyword: finish

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PCB Quality and Reliability affected by Galvanic Reaction (Galvanic Reaction이 인쇄회로기판(PCB)의 품질과 신뢰성에 끼치는 영향)

  • Lee, Jin-Ho
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2012.05a
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    • pp.38-56
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    • 2012
  • 현재 사용되고 있는 다양한 Surface Finish들 중 대표적인 것들을 골라 Galvanic Reaction에 의해 어떤 품질 및 신뢰성 문제가 산업현장에서 발생되고 있는지 살펴보고 그리고 개선의 방법으로는 어떤 것들이 있는지 검토해 보았다.

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Development of Environment-friendly Board in Construction Materials (친환경 건설 성형판재 개발을 위한 기초적 연구)

  • Seo, Deok-Hyun;Kim, Seong-Sik;Jeong, Yong-Sik;Im, Nam-Ki;Lee, Sang-Beom
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.1 s.15
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    • pp.69-74
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    • 2005
  • The construction of house in Korea firstly has been made up quantitative supply and margin of confined land until the latest. But, residents interest of living environment, demand of high-quality has varied with the latest elevation of life quality Specially, the interest for environment-friendly architecture is increased by the recent well-being trend in 2002, So, construction company and construction materials manufacturing industry are trying to offer more healthy and agreeable indoor aerial environment. Related circles do their best to commercialize and develop environment-friendly finish materials which influence indoor aerial environment. Therefore, in this study, that developing raw material and productive system that can minimize hazardous article quality discharge with formaldehyde in development of correction of deformities board such as plywood that is used mainly by a environment-friendly materials indoor finish, and examines application possibility of construction correction of deformities board through properties of matter examination by purpose, do.

Practical Application of Lead-free Solder in Electronic Products

  • Cho Il-Je;Chae Kyu-Sang;Min Jae-Sang;Kim Ik-Joo
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2004.09a
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    • pp.93-99
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    • 2004
  • At present, LG Electronics pushes ahead to eliminate the Pb(Lead) -a hazardous material- from all products. Especially, we have performed to select the optimum standard composition of lead free alloy for the application to products for about 3 years from 2000. These days, we have the chance for applying to the mass-production. This project constructed the system for applying the lead free solders on consumer electronic products, which is one of the major products of the LG Electronics. To select the lead free solders with corresponding to the product features, we have passed through the test and applied with Sn-3.0Ag-0.5Cu alloy system to our products, and for the application to the high melting temperature composition, we secured the thermal resistance of the many parts and substrate and optimized the processing conditions. We have operated the temperature cycling test and the high temperature storage test under the standards to confirm the reliability of the products. On these samples, we considered the consequence of our decision by the operating test. For the long life time of the product, we have operated the temperature cycling test at $-45^{\circ}C-+125^{\circ}C$, 1 cycle/hour, 1000 cycles. Also we have tested the tin whisker growth about lead free plating on lead finish. We have analyzed with the SEM, EDS and any other equipment for confirming the failure mode at the joint and the tin whisker growth on lead free finish.

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Current Trends of Vibration-Assisted Machining in Micro/Nano Scales (초정밀 진동 보조 가공 연구 동향)

  • Lee, Moon-Gu;Jeon, Yong-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.8
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    • pp.834-839
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    • 2012
  • Recently, mechanical components with miniaturized size, complex shape and fine surface are on demand from industries such as mobile electronics, medical devices and defense. The size of them is smaller than several millimeters, the shape has micro-holes, curve, or multi-step and the surface is mirror-like. This features are not able to be machined with the conventional machining, therefore electro-discharge machining (EDM), cutting, and laser machining have been applied. If the technologies are assisted by vibration, high aspect ratio and good surface are to be achieved. In this paper, prior and current researches of vibration-assisted machining are reviewed. Machining mechanisms with vibration-assisting are explained, their effects are shown, and vibrating apparatuses are discussed. Especially, comparison between with and without vibration assisting is presented. This review shows the vibration-assisted machining is effectively fabricate the components with small and complicated shape and fine surface finish.

An unified rough and finish cut algorithm for NC machining of free form pockets with general polygon - Part 2. Experiment (일반적인 내벽을 가진 자유바닥 곡면 파켓의 NC 가공을 위한 단일화된 황삭과 정삭 알고리즘 - Part 2. Experiment)

  • Choi, Yong-Hoon;Kim, Sang-Jin
    • Journal of Korea Society of Industrial Information Systems
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    • v.12 no.1
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    • pp.46-53
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    • 2007
  • NC (Numerical Control) code for the tool path needs to be generated efficiently for machining of free form pockets with arbitrary wall geometry on a three axis CNC machine. The unified rough and finish cut algorithm and the tool motion is graphically simulated in Part 1. In this paper, a grid based 3D navigation algorithm simulated in Part 1 for generating NC tool path data for both linear interpolation and a combination of linear and circular interpolation for three-axis CNC milling of general pockets with sculptured bottom surfaces is experimentally performed and verified.

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A Study of a New Precision Finishing Process for Inside Surface of Silicon Nitride Fine Ceramic Pipe by Application of Magnetic Abrasive Machining (자기 연마법에 의한 질화 규소계 세라믹 파이프 내면의 경면 연마 특성에 관한 연구)

  • Park, Won-Gyu;Shinmura, Takeo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.1
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    • pp.47-53
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    • 2001
  • Results ar presented of a new process for internal precision finishing of slender fine ceramic pipes using a magnetic field generated by a permanent magnets. For finishing the interior surface of a long pipe, a new type of finishing equipment was developed which can be very easily used in an industrial surrounding. In general, the pipe is so slender that a conventional finishing tool is hardly inserted into the pipe deeply, being impossible to finish. Therefore, a new technology has been considered to finish inside of a slender ceramic pipe by a simple technique. In this experimental, Magnetic Abrasive Machining is applied for the inner surface of silicon nitride fine ceramic pipe using ferromagnetic particles mixed with chromium-oxide powder. It is shown the initial roughness of 2.6㎛ Ry(0.42㎛ Ra) in the inside surface can be precisely finished to the roughness of 0.1㎛ Ry(0.01㎛ Ra). This paper discusses the outline of the processing by the application of magnetic abrasive machining and a few finishing characteristics.

Analysis of Noise Environment of Cafe Occupants According to Interior Finishing (실내 인테리어 마감재에 따른 카페 재실자의 소음 환경 영향 분석)

  • Lee, Soo Han;Yun, Huiseung;Wi, Seunghwan;Kim, Sumin
    • Journal of the Korea Furniture Society
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    • v.28 no.4
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    • pp.355-361
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    • 2017
  • Indoor noise environment is an important factor when it comes to occupants comfort, especially in cafe. Results of the survey, 33.9% of occupants were feel unpleasant and sensitive about noise environment. Noise in cafe fluctuate depending on the finishing of both wall and ceiling, volume of the room, and the number of occupants in the room. Therefore, the noise meter device was used for measurement of various under conditions. Also, the subjective assessment of occupant noise was conducted through questionnaires. When the interior finish was exposed concrete, the maximum value of the noise measurement was 66.6 dB and the minimum value was 63 dB, respectively. Also, the result of subjective assessment of unpleasant noise were 5.43 and 4.96 point of 10 point of noise and echo, respectively. Otherwise, the interior finish was gypsum board, the maximum value of the noise measurement was 73.8 dB and the minimum value was 60.4 dB, respectively. Also, the result of subjective assessment of unpleasant noise were 3.88 and 3.95 point of 10 point of noise and echo, respectively. The results of the study showed that the noises and echoes in the cafes were lower than when did not.