• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.2
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• pp.130-136
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• 2009

Turbine, which is one of major components in nuclear power plants, requires reliable nondestructive inspections. But, accessibility of transducers is limited and interpretation of acquired signals is not easy at all due to the complication. So, in this study, we have fabricated mock-up specimens of real size and shape. we applied pulse-echo method and time-of-flight diffraction(TOFD) method for precise inspection of turbine key and wheel bore. And phased array ultrasonic testing method was adopted for wheel dovetail of turbines by using mock-up. Furthermore, an automatic scanner system was developed for in-service inspection of the developed methods.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.463-470
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• 1995

설계, 가공, 조립, 검사기술로 대표되는 생산시스템의 근간 기술은 공작기계에 의한 부품가공 소위, 기계 가공 기술이다. 가공에 필요한 NC 프로그램의 효율적인 관리를 위해 이용되던 종래의 DNC(Direct Numerical Control) 는 가공 Cell 의 효율을 높이기 위해, CNC 가공기 및 주변기기에 대한 실시간 감시/제어기능을 가진 분산제어시스템( DNC(Distributed Numerical Control)으로 발전하고있다. 본 연구에서는 이기종 CNC로 이루어진 가공 Cell에 적합 하고, 경제성, 범용성 및 확장성을 고려하여 RS485 Network 및 RS232C를 이용하여각 CNC 공작기계 및 주변기기와 연결 해서 실시간(Real Time) 동시작업(Multi Tasking) 가능한 DNC 시스템을 개발하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1997.04a
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• pp.223-231
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• 1997

내열성복합재료와 Steel 구조물 사이의 좁고 긴 원통형 공간을 내열성 폴리우레탄 재료로 충전하는 연구를 수행하였다. 충전재료를 결정하기 위하여 3종의 폴리우레탄과 에폭시수지를 선정, 시험하여 내열성, 흐름성, 접착성, 경도측정 등을 통하여 최종 결정하였으며 선정된 폴리우레탄을 충전하기 위하여 Resin Transfer Molding(RTM) 방법을 사용하였다. 충전 공정의 적용여부를 판단하기 위하여 아크릴을 이용한 RTM치구를 설계, 제작하여 시험하였다. 충전된 조립체는 비파괴 검사를 통하여 접착, 기공 등을 검사하였으며 지상연소시험을 통하여 내열성능을 평가하였다.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.6
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• pp.598-606
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• 2001

Recently, semiconductor packages trend to be thinner, which makes difficult to detect defects therein. A preconditioning test is generally performed to evaluate the reliability of semiconductor packages. The test procedure includes two scanning acoustic microscope (SAM) tests at the beginning and end of the entire test, in order to help detect physical defects such as delaminations and package cracks. In particular, of primary concern are package cracks and delaminations caused by moisture absorbed under ambient conditions. This paper discusses the failure mechanism associated with the moisture absorbed and encapsulated in semiconductors, and the use SAM to detect failures such as tracks and delaminations grown during the preconditioning test.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.628-631
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• 2010

환경문제에 대한 관심으로 자동차에 대한 경량화가 요구되는 동시에 안전규제가 강화 되고 있어, 높은 인장강도를 가지는 고강도 강의 차체 적용 비율이 점차 증가하고 있다. 또한, 자동차 1대를 조립하기 위한 저항 점용접 횟수를 줄이고, 용접부에 충격안정성을 확보하기 위한 관심이 고조되고 있다. 따라서, 국내 자동차 산업에서 용접부의 신뢰성을 보장하기 다양한 비파괴 검사를 적용하고 있으며, 생산 공정에 적용하고 있다. 그중에서 용접 전극 사이에서 동저항(Dynamic resistance, 용접 공정중모재의 저항값의 변화)을 계측하여 용접성을 평가하는 방법이 제시되고, 차체 조립공정 중에 적용하려는 시도가 이루어지고 있다. 본 연구에서는 자동차 차체용 냉간 압연강판(590MPa dual-phase steel)을 인버터 DC 저항 점 용접하여, 용접전극 사이에서 동저항을 측정 하였다. 용접성은 인장전단 강도로 평가하였고, 용접 공정 변수는 용접 전류, 용접 시간, 가압력을 선정하였다. 동저항 그래프의 ${\alpha}$-peak와 ${\beta}$-peak값을 인장전단 강도에 따라 회귀 분석하여, 동저항에 따른 인장전단 강도를 예측하였다. 추가적으로, 용접부의 외관 형상 중에 압흔 깊이와 압흔자국 지름에 대한 회귀분석을 실시하였으며, 용접부 형상에 대한 신뢰성을 부여하였다.

• Journal of Preventive Medicine and Public Health
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• v.29 no.4 s.55
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• pp.785-799
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• 1996

We investigated the 1,004 workers who worked in a automobile factory to study the epidemiologic characterists of dermatoses due to cutting oils. Among the workers, 667(66.4%) answered the questionaire. They are belong to 5 departments of the factory-the Engine-Work(258 workers), Gasoline engine Assembly(210), Diesel engine Assembly(96), Power train Work(86), Power train Assembly(17). We measured the oil mist concentration in air of the departments and examined the workers who had dermatologic symptoms. The results were follows; 1) Oil mist concentration ; Of all measured points(52),9 points(17.2%) exeeded $5mg/m^3$- the time-weighed PEL-and one department had a upper confidence limit(95%) higher than $5mg/m^3$. 2) Dermatologists examined 213 workers. 172 of them complained any skin symptoms at that time - itching(32.5%), papule(21.6%), scale(15.7%), vesicle(12.5%) in order. The abnormal skin site found by dermatologist were palm(29.3%), finger & nail(24.6%), forearm(16.2%), back of hand(8.4%) in order. 3) As the result of physical examination, we found that 160 workers had skin diseases. Contact dermatitis was the most common; 69 workers had contact dermatitis alone(43.1%), 11 had contact dermatitis with acne(6.9%), 10 had contact dermatitis with folliculitis(6.3%), 1 had contact dermatitis with acne & folliculitis, and 1 had contact dermatitis with abnormal pigmentation. Others were folliculitis(9 workers, 5.6%), acne(8, 5.0%), folliculitis & acne (2, 1.2%), keratosis(1, 0.6%), abnormal pigmentation (1, 0.6%), and non-specific hand eczema (47, 29.3%). 4) The prevalence of any skin diseases was 34.0 pet 100 in cutting oil users, and 13.3 per 100 in non- users. Especially, the prevalence of contact dermatitis was 23.0 per 100 in cutting oil users and 23.0 per 100 in non-users. 5) We tried patch test(standard serise, oil serise, organic solvents) on 49 patients to differentiate allergic contact dermatitis from irritant contact dermatitis and found 20 were positive. 6) In a multivariate analysis(independant=age, tenure, kinds of cutting oil), the risk of skin diseases was higher in the water-based cutting oil user and both oil user than non-user or neat oil user(odds ratio were 2.16 and 2.78, respectively). And the risk of contact dermatitis was much higher at the same groups(odds ratio were 5.16 and 6.82, respectively).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.5906-5911
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• 2014

Currently, there are many processes of package assembly and inspections of real fields that examine whether a manufactured semiconductor can be operated regularly and can endure low humidity or high temperatures. As the inspection equipment of a semiconductor test handler picker has been used at the inspection process, these inspection equipment frames were modelled in 3D and these models were analyzed using 3 kinds of fatigue loadings. As the analysis result, maximum deformation occurred at the midparts of the frames at cases 1 and 2. Among the cases of nonuniform fatigue loads, the 'SAE bracket history' with the severest change in load became the most unstable but the 'Sample history' became the most stable. Fatigue analysis result can be used effectively with the design of an inspecting equipment frame of a semiconductor test handler picker to examine the prevention and durability against damage.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.4
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• pp.161-168
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• 2006

In this paper, we propose a method for the pattern inspection of LCD module using the color compensation and pattern matching. The pattern matching is generally used for the inspection method of LCD module at the industry. LCD module has many defections such as the brightness difference of the back light, the optic feature of liquid crystal, the difference of the light penetrated by driving LCD and the color difference by the lighting. The conventional method without the color compensation can not solve these defections and decreases the efficiency of inspecting LCD module. The method proposed to inspect defective badness through the pattern matching after it compensated color difference of the LCD occurred by the various causes. At first, it revises with setting by standard tone of color with the LCD pattern of the reference image. And It perform the preprocessing and pattern matching algorithm on the compensated image. In experiment, we confirmed that this algorithm is useful to detect some defections of LCD module. The proposed methods was easy to detect the faulty product.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.8
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• pp.965-970
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• 2011

We develop a diagnostic system to monitor failures in an engine-assembly line. Existing techniques such as sensory analysis, time domain analysis, frequency analysis, and statistical analysis have limitations in the diagnosis of engine-assembly failure when there are abnormal vibration waveforms (crashing and damping signals) during the assembly. We use a wavelet technique to deal with crashing and damping signals. We also implement a new technique for developing diagnostic rules from sensor data, and we demonstrate its validity.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1385-1386
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• 2007

전통적으로 초고압 지중케이블 접속함으로 현장에서 절연을 형성하여 전기적 성능을 유지하는 TMJ(Tape Molded Joint), TJ(Taped Joint), EMJ(Extruded Molding Joint) 및 공장에서 절연물을 가공하여 현장에서 조립만으로 설치를 완료하게 되는 PJ(Prefabricated Joint), PMJ(Pre-Molded Joint) 등이 사용되어 왔다. 최근에 PMJ에 사용되는 재료의 발전과 PMJ의 조립시간 단축, 원가 절감 및 공장 출하시 검사에 의한 신뢰성 향상으로 지중케이블 접속함 시장에서 PMJ의 비중이 점차 확대 되어가고 있다. 이에 당사는 이미 230kV급 PMJ의 개발을 완료하였으며, 이러한 기술적 배경을 바탕으로 현재 PMJ로서는 세계에서 최고 전압급에 속하는 400kV급 PMJ의 개발을 완료하게되었다.