• 대한안전경영과학회지
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• 제7권2호
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• pp.85-94
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• 2005

The purpose of this study is to execute the investigation of injurious factors causing muscle-skeletal diseases at an automotive glass manufacturing company and, on the basis of the results, to enhance productivity by the improvement of working environment. By using an survey and an ergonomic evaluation method, symptoms of muscle-skeletal diseases of workers and working postures at each process were analyzed, and quantitative evaluation of muscle-skeletal disease risk against each process was performed. Based on the result of the evaluation, to enhance the working environment, improvement of worktable, working space, tools, and outfit was suggested, and induction of mechanical system was also suggested. Suggested improvement plan was applied to the workplace step by step and it is confirmed that improvement plan not only removes the injurious factors of muscle-skeletal diseases but also is effective to enhance productivity.

• Journal of Advanced Marine Engineering and Technology
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• 제18권4호
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• pp.62-68
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• 1994

Recently, the trends toward reduction in size and weight of industrial products increased the application of micro hole for manufacturing gadgets of high precision and gave rise to a great deal of interest for micro hole drilling M/C. Quite a few research work is performed on micro drilling on domestic basis compared with the tendency of analyzing cutting mechanism, adaptive control, monitoring of generally available drills of diameter greater than 1mm. This study adresses the design, manufacturing and controlling a micro hole drilling M/C with the overload detection instrument and the step feed mechanism. Controlling and monitoring of the drilling process are acomplished on PC basis for more user interfaces and effectiveness. The test machine of the results of this research shows a good foundation for extending further micro hole machining technique.

• 산업경영시스템학회지
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• 제19권39호
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• pp.193-204
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• 1996

본 연구는 FMC(Flexible Manufacturing Cell)에 있어 상호 간섭이 없는 부품의 흐름을 제어하기 위한 교착제거방법(Deadlock Avoidance Method)에 대한 제안으로서, 이 방법이 주요한 장점은 첫째, FMC의 환경을 쉽게 적용시킬 수 있고 둘째, 공정상의 부품에 대한 dispatching 모듈이 협력하도록 설계되어 있다는 것이다. 교착제거방법은 두 개의 모듈로 구성되어 있는데 이는 순환발견알고리즘(A Cycle Detection Algorithm)과 원료주문 정책으로서, 특이할 만한 사항은 순환발견알고리즘을 채용하더라도 원료주문정책이 잘못될 수 있기 때문에 교착제거방법에 있어서 원료주문정책은 매우 중요하다는 것이다. 이를 위하여 교착전의 N-step 교착을 제거하고, 발견할 수 있는 교착제거방법과 N-step의 사전주무정책을 제시하였다.

• 한국기계가공학회지
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• 제10권4호
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• pp.16-21
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• 2011

This paper described an analysis of dynamic mechanism for the industrial two-step folding automatic door using commercial software packages. Two modeling types of operating on the guide rail, the sliding one and the rolling, were adopted to investigate effects of impact force when the door ascends the guide rail. The magnitude of impact force was found very peaklike large over an initial duration of the door's moving up. The amount of damping coefficient for alleviating this shock was controlled to such a moderate degree that the operating conditions can be obtained for the purpose of design. Moreover the behavior of both dynamic stress and deformation were observed for acquirement of structural reliabilities of the combined guide rail and rolling mechanism. This research will be a very useful tool in the near future for the dynamic analysis of the multi-step folding automatic door.

• 한국생산제조학회지
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• 제8권1호
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• pp.81-88
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• 1999

This paper was carried out to know the influence of advanced austempered ductile cast iron (ADI) on the tool life and mechanical properties of drilling machinability. For manufactured method of ADI, the spheroidal graphite cast iron were austenized at 90$0^{\circ}C$ for 1 hour and then austempered for 2 hour at 37$0^{\circ}C$ in the salt bath. And interrelationship has been investigated between tool life and mechanical characteristics of specimen material on drilling condition when the ordinary and step-feed drilling are carried out to drill holes of specimens. Tensile strength and hardness of ADI decrease and elongation of ADI increases with the increase austempered temperature. It is known that about 2 times of tool life in the case of step-feed decreases compared with ordinary feed due to the high hardness of ADI and hardness ascribed to the fact that retained austenite became to martensite state due to cutting heat in drilling. Under the constant feed rate 0.1mm/rev relation between hardness and length of end tip after drilling can be formularized to Hv=$788.46L^{-0.096}$ for the cutting speed 6.1m/min.

• 한국생산제조학회지
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• 제25권1호
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• pp.89-95
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• 2016

This study investigated the design factors of the opening area in order to consider the kinematic stability of a valve plate, conducting an analysis of the reduction effects of pressure pulsation and flow ripple depending on the design factors, using the $SimulationX^{(R)}$ (Germany) hydraulic analysis program. Further, we performed a structure analysis to confirm the kinematic stability of the valve plate in a swash plate type piston pump, and analyzed the effects of pulsation on a 1-step V-type notch, 2-step V-type notch, and 2-step U-type notch to determine the effects of pulsation reduction. Finally, we show the effectiveness of our proposed design of the pre-compression sections on a valve plate in terms of low pulsation by using the hydraulic analysis program, $SimulationX^{(R)}$.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1996년도 춘계공동학술대회논문집; 공군사관학교, 청주; 26-27 Apr. 1996
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• pp.121-124
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• 1996

In general, cellular manufacturing system can be constructed by the following two steps. The first step forms machine cells and part families, and the second step determines cell layout based on the result of first step. Cell layout has to be considered when cell is formed becauese the result of cell formation affects it. This paper presents a cell formation algorithm and proposes an integrated mathematical model for cell formation and cell layout. The cell formation algorithm minimizes the number of exceptional element in cellular manufacturing system. New concept for similarity and incapability is introduced, based on machine-operation incidence matrix and part-operation incidence matrix. One is similarity between the machines, the other is similarity between preliminary machine cells and machines. The incapability identifies relations between machine cells and parts. In this procedure, only parts without an exceptional element are assigned to machine cell. Bottleneck parts are considered with cell layout design in an integrated mathematical model. The integrated mathematical model determines cell layout and assigns bottleneck parts to minimize the number of exceptional element and intercell moving distance, based on linearixed 0-1 integer programming. The proposed algorithm is illustrated by using numerical examples.

• 대한화장품학회지
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• 제24권3호
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• pp.96-104
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• 1998

It was possible to produce W/O/W one step multiple emulsion on the system which satisfied following conditions. 1. 1-5％ of hydrophilic liquid surfactant over HLB20 and lipophilic liquid surfactant which has HLB 3∼5 2. Non wax copolymers as oil thickener 3. More than 0.5％ of carbomer as aqueous thickener 4. The manufacturing process which neutralize the dispersed carbomer (2.0％ in water), after emulsifying. For the selective addition into inner and outer aqueous phase, we melted the glucose in water before emulsifying. Using an Anthrone analysis method, we analyzed the encapsulation yield of glucose in inner water phase. It was possible to raise the water encapsulation yield of the multiple emulsion through the following conditions. 1. Using of anionic hydrophilic surfactant(HLB 40) and lipophilic surfactant (HLB 3∼5) 2. Controlling the ratio of hydrophilic surfactant and lipophilic surfactant 3. Strengthening interface with increase of non wax oil thickener. When the separated adding process of glucose was adopted, approximately 85％ of glucose was added selectively within inner aqueous phase.

• 한국생산제조학회지
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• 제23권5호
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• pp.512-518
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• 2014

In this paper, the influence of part shape complexity and die type on forming accuracy in incremental sheet metal forming is presented. The part shape complexities are classified into two types, namely, of one and two-step shapes. Correspondingly, die types are classified into three types, namely, of no-, partial, and full die types. The experimental tests are performed separately on negative and positive forming methods. It is shown that for the one-step shape, there are no significant differences in forming errors between the cases of no- and full die types when the negative forming method is used. Furthermore, the full die type is better than the partial die when positive forming is used. For the two-step shape case, the full die type always exhibits better forming accuracy than the no- and partial die types, irrespective of the forming method used.

• 한국기계가공학회지
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• 제19권12호
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• pp.8-13
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• 2020

Seamless pipes are fabricated by drilling a hole in a cylindrical material and drawing the material to the desired diameter. These pipes are used in environments where high reliability is required. In this study, the pipe drawing process was simulated using DEFORM, a commercial finite element method (FEM) analysis program. The outer diameter of the steel cylinder used herein before drawing was 70 mm, and the target outer diameter was 58 mm. The drawing process consisted of two stages. In this study, the effect of cross-sectional reduction rate on the pipe was investigated by varying the cross-sectional reduction rate in each step to achieve the target outer diameter. The results of this study showed that the first section reduction rate of 26% and the second section reduction rate of 13.9% caused the lowest damage to the material. Moreover, the FEM simulation results confirmed the influence of the drawing die angle on the pipe drawing process. The drawing die angles of 15° in the first step and 9° in the second step caused the least damage to the material.