• Elastomers and Composites
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• v.54 no.3
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• pp.175-181
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• 2019

The research and development of high-performance polymer materials with excellent gas barrier properties has gained considerable attention from the viewpoint of expanding their applications in various fields, including tire automobile parts and the polymer film industry. Natural rubber (NR) has been widely used as a rubber material in real-life, but its application is limited owing to its poor gas barrier properties. In this paper, we study the gas barrier properties of NR, epoxidized natural rubber (ENR), and their blend compositions by using molecular simulation. The results show that ENR-50 has superior oxygen barrier properties than those of NR. Moreover, the oxygen barrier properties of a blend of NR/ENR-50 improve with increasing volume fraction of ENR-50. The trend of improved oxygen barrier properties of NR, ENR-50, and their blend is in good agreement with experimental observations.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2022.10a
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• pp.275-276
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• 2022

본 연구에서는 비즈니스 연속성 경영시스템(ISO 22301)이 현재 선진국에 진입해 있는 대한민국 사회에 당면과제이며 이슈가 되고 있는 중대산업재해 감소에 미치는 영향을 자동차 제조업을 중심으로 분석하고자 한다. ISO 22301은 2012년 처음으로 HLS (High Level Structure)작성되었으며 이를 통하여 조직의 비즈니스에 대하여 비즈니스 연속성을 수립하여 조직에서 발생할 수 있는 비즈니스 중단에 대비하고 있다. 또한 중대재해는 「산업안전보건법」상 산업재해 중 사망자가 1명 이상 발생하거나, 6개월 이상 치료가 필요한 부상자가 2명 이상 발생하거나, 동일한 유해요인으로 직업성 질병자가 1년에 3명 이상 발생한 경우를 말한다(법제처, 2021).

• Design & Manufacturing
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• v.18 no.1
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• pp.32-38
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• 2024

Securing technology to quickly develop products and launch them when needed has become an essential factor in corporate competitiveness to keep up with the rapidly changing automotive market. The automotive industry is launching various line-up electric vehicles in the era of the great transformation of electric vehicles in internal combustion locomotives. As for electric vehicles, the use of aluminum, a lightweight material, is increasing as a prerequisite for existing products to be lightweight depending on the weight of the battery. In this study, mold manufacturing and products were produced based on the results of optimized molding analysis during aluminum press molding. The results reflecting the optimal conditions of the molding analysis and the results of the actual production were compared and analyzed through digital 3D scanner equipment rather than analog to verify the accuracy, efficiency, and effectiveness.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.1
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• pp.71-81
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• 2009

Die steel for plastic molding were used as mold material of automobile parts and electronic component industry. The material of this paper has superior to mechanical properties, such as repair weldability, corrosion resistance and high temperature strength, required mold parts for semitransparent. Laser-induced surface hardening technology is widely adopted to improver fatigue life and wear resistance via localized hardening at the surface of mold parts. The objective of this research work is to investigate on the characteristics of surface hardening of the laser process parameters, such as beam travel speed, laser power and defocsued spot position, for the case of die steel for plastic molding. Lens for surface hardening of large area is plano-convex type with elliptical profile to maintain uniform laser irradiation. According to the experimental results, large size of hardened layer at the surface of die steel for plastic molding was achieved, and microstructure of this layer was lath martensite. Optimal surface status and mechanical property of hardened layer could be obtained at 1095Watt, $0.25{\sim}0.3m/min$, 0mm (focal length: 232mm) for laser power, beam travel speed, and focal position. Where, heat input was $0.793{\times}10^{3}J/cm^2$, and width of hardened layer was 27.58mm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.85-90
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• 2010

Friction welding is a common practice to join axially symmetrical parts for automobile industry applications. The shaft for automobile reverse idle gear is generally produced by forging steel, SF 45. This method is not so good because of high cost of material and production. In this study, in order to investigate the possibility of application of SM 45C to SF 45 dissimilar friction welding, the dissimilar friction welded joints were performed using 20 mm diameter solid bar in forging steel(SF 45) to carbon steel(SM 45C). The optimal friction welding parameters were selected to ensure reliable quality welds on the basis of visual examination, tensile test, micro-Virkers hardness surveys of the bond of area and optical microstructure investigations for welded joint parts. Finally, post weld heat treatment(PWHT) of the high-frequency induction hardening was performed for the friction welded specimens under the optimal welding conditions. And then, the mechanical properties were compared for as-welded and PWHT in SM 45C to SF 45.

• Journal of Ocean Engineering and Technology
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• v.23 no.3
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• pp.46-52
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• 2009

Nowadays, many components in automobile, aircraft, offshore structure and industry require lightness and high strength. However, since developments of advanced materials have limitations, it mainly is applying to method of surface hardening. This study offered research about camshaft that is one among engine important component. The material used in this study is 0.53% carbon steel as structure material of camshaft, splineshaft, coupling, pulley, driveshaft et cetera. Camshaft is processed using mainly carbon steel, and receives wear and fatigue by special quality high speed of parts. Therefore, camshaft need surface hardening to improve camshaft's fatigue life and increase durability of engine. This study compare to residual stress and martensite microstructure created by high frequency induction treatment, and these results lead to the conclusion of fatigue crack growth characteristics.

• Journal of Energy Engineering
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• v.29 no.3
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• pp.50-56
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• 2020

Currently, 3D printing technology is a new revolutionary additive manufacturing process that can be used for making three dimensional solid objects from digital films. In 2019, this 3D printing technology spreading vigorously in production parts (57%), bridge production (39%), tooling, fixtures, jigs (37%), repair, and maintenance (38%). The applications of 3D printing are expanding to the defense, aerospace, medical field, and automobile industry. The raw materials are playing a key role in 3D printing. Various additive materials such as plastics, polymers, resins, steel, and metals are used for 3D printing to create a variety of designs. The main advantage of the green cement for 3D printing is to enhance the mechanical properties, and durability to meet the high-quality material using in construction. There are several advantages with 3D printing is a limited waste generation, eco-friendly process, economy, 20 times faster, and less time-consuming. This research article reveals that the role of green cement as an additive material for 3D printing.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.4
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• pp.301-308
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• 2006

Today's automobiles are changing into miniaturization and light weight for saving natural resources and energies. In order to raise the sufficiency of fuel consumption, new mechanism and components are required. Therefore, the expectations on the new materials are very high. Especially, Al materials are widely used to reduce the motors weight. Al using in automobiles is mostly casting material, and the material is developing rapidly in step with technical innovation. Al die casting has become an important field, as we are turning today's motor into light weight. One of the parts in steering system, valve housing, plays a role to reduce the operating effort of drivers. If valve housing being a part of steering system is produced by gravity casting, the space that manufacturing equipments are installed will be increased, and more energies and workers will be needed.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.3
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• pp.381-392
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• 2020

The necessity and the importance of the remanufacturing are increasing day by day along with environmental problems. Many studies are being conducted on remanufacturing, but the research for cleaning is much lacking. This study aims to evaluate the effective cleaning method for remanufacturing of start motors, one of the automobile parts. The cleaning process consists of oil stain removal, drying and rust removal processes. In this study, the two processes were conducted except for the drying process which has little influence on cleaning. The methodology for cleaning agent selection, degreasing and rust removal process was presented. For each methodology, five analysis factors were calculated by two-way comparison according to the process, and the values were evaluated quantitatively by substituting them into the evaluation table. In the selection of cleaning agent, neutral system, ultrasonic cleaning in degreasing, and grinding in rust removal were selected as the best cleaning methods.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.267-275
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• 1998

As social and economic environments rapidly change, all enterprises are struggling for the 21C. K company, a motor company, is building a new production system by one way of paradigm shift to get the competitive power in the market. This system includes concepts of the thinking shift from maker's view to consumers' view when it makes cars. Simultaneously, K company has been applying another new method 'Interchanges of Different Section of Industry' to make more competitive vendors since 1996. The old method, used until 1995, had worked well and gained lots of effects during the reform activities. But after the technical supervisors from K company had left almost everything went back to the starting point in the vendor company. The major causes of this phenomenon are that there were no ‘structure’ to maintain the reforming activities. We have confirmed that ‘Interchanges of Different Section of Industry’ is a good way to let this ‘structure’ exist continuously. After we compared and analyzed merits or demerits of this system through the experience of applying it to a vendor C, we have suggested more progressive method by strengthening the merits and removing the demerits.