• 소성∙가공
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• 제25권4호
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• pp.227-234
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• 2016

In the transportation between countries using container, too many empty containers must be transported due to the transportation unbalance. For transportation efficiency, therefore, foldable containers are being developed. Hinge brackets are important parts of foldable containers because great force is applied on the hinges during loading onto and unloading from ships. In this study, the hinge bracket for a foldable container is designed to be made using thick plate or bulk materials to endure the heavy loads. The forming process for the hinge bracket using a thick plate is designed via numerical analysis. First of all, the shape of bracket is designed for the better formability. Bending and successive side wall thickening processes are employed for the forming of the hinge bracket. Maximum thickening that can be achieved in a single stage of forming without a folding defect is determined and three stage of thickening processes are designed.

• 청정기술
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• 제14권4호
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• pp.232-241
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• 2008

EU의 WEEE 지침에는 전기전자제품의 생산자들이 반드시 달성하여야 하는 재활용률과 재생률의 목표치가 설정되어 있다. 본 연구에서는 전기전자제품의 생산자들이 개발되는 제품의 재활용가능률과 재생가능률을 산정해 보는데 필요한 부품과 소재들의 재활용률과 재생률의 기준을 만들어 보았다. 먼저 전기전자제품의 재활용공정과 부품 및 소재별 재활용 및 재생특성을 분석해 보았으며, 유럽 현지 업체들의 처리결과에 따른 재활용률과 관련된 자료들을 조사하여 분석하였다. 이러한 결과로 작성된 재활용률과 재생률 DB는 유럽의 전문가의 의견을 반영하여 개선하였다.

• 소성∙가공
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• 제17권2호
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• pp.130-134
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• 2008

Resource and energy saving is a very important practice for the future as well as for today. Weight saving of structural parts, which are formed by extrusion, plays a key role in manufacturing field. The cross-sections of extruded parts with industrial aluminum are constant in the axial direction by conventional extrusion method. Especially, these aluminum parts used and manufactured in the car industry need other processes to vary the cross-section in the axial direction. However, applications of these parts are often limited by high cost. If the cross-section of the parts is variable by only extrusion with newly developed method, the application of extruded aluminum parts will actually increase. Therefore, a new CNC extruder that can control the section area of a car part was invented for the first time in the nation. Using the extrusion machine, the experiment was performed to validate its workability during the variable section extrusion process. Also, numerical analysis was carried out to investigate the flow mode with different speeds of main ram and various pocket shapes of a die-set in the variable section extrusion process.

• 한국기계가공학회지
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• 제15권5호
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• pp.39-47
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• 2016

Nowadays, several welding processes are generally used to join parts together, and the materials are generally steel, aluminum, copper, stainless steel, and other difficult-to-weld materials. If a proper welding process is chosen, it is helpful for welding parts. However, there is no desirable technique for appropriately deciding on the welding process in the industry. Therefore, an appropriate method of selecting a welding process is needed for the novice worker in the industry. In this sense, a new analytic network process (ANP) technique is used for effective decision making in welding. By considering several criteria in ANP, a selection method is suggested to decide on the proper welding process. In the study, several criteria were considered for the proper welding of parts. By considering a matrix of prior interdependence effects among various welding processes, a decision-making method based on an ANP is accomplished using a weighting matrix, which is supposed to select an appropriate welding process. In addition, for appropriate decision criteria of the welding process, several factors, such as material, shape, precision, economics, and equipment, are used to accomplish the ANP algorithm. Moreover, the final weighting matrix is calculated following its ANP strategy. Furthermore, this decision-making technique is applied to both stainless razor spot joining and thick steel pipe joining. The results show its reliability and practicality, and the novice engineer and manager can use this technique to determine the best welding process.

• 패션비즈니스
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• 제15권2호
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• pp.145-159
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• 2011

The study aimed to analyze the status quo of manufacturing work environment and the work clothes' clothing comfort and wearer mobility of welding and grinding work processes in the machine and shipbuilding industries in South Korea. A questionnaire survey was conducted for the study, which consisted of questions about work clothes' clothing comfort and wearer mobility according to body parts. The findings derived from the research were: the high impact levels of work environment factors on welding and grinding work processes were noise, metal fragment, superheat, toxic gas, UV ray factors. Subject workers' assessment of work clothes' clothing pressures were in the levels between 3 (i.e. moderate) and 4 (i.e. comfortable) in a range of 5-point scale. The impact levels of wearer mobility factor were high on the work processes of welding and grinding in machine and grinding in shipbuilding. While welding process in shipbuilding showed a 'moderate' wearer mobility level and this was because its work postures were uncomfortable yet the rate of the motion change was low. The consideration to develop the work clothes specialized for certain work processes should include the materials' protecting performance from the hazardous work environment factors; and work clothes' designs that provides workers with maximized clothing comfort and wearer mobility for bending or tilting postures of upper, lower and lateral body parts defined in the study.

• 한국분말재료학회지
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• 제21권4호
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• pp.294-300
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• 2014

The connecting rod is one of the most important parts in automotive engines, transforming the reciprocal motion of a piston generated by internal combustion into the rotational motion of a crankshaft. Recent advances in high performance automobile engines demand corresponding technological breakthroughs in the materials for engine parts. In the present research, the powder metallurgy (P/M) process was used to replace conventional quenching and/or tempering processes for mass production and ultimately for more cost-efficient manufacturing of high strength connecting rods. The development of P/M alloy powder was undertaken not only to achieve the improvement in mechanical properties, but also to enhance the machinability of the P/M processed connecting rods. Specifically $MoS_2$ powders were added as lubricants to non-normalizing Fe-Cr-Mn-V-C alloy powder to improve the post-sintering machinability. The effects of $MoS_2$ addition on the microstructure, mechanical properties, and machining characteristics were investigated.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1994년도 박판성형기술의 진보
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• pp.1-9
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• 1994

Three recent developments made at Rensselaer in sheet material forming processes are briefly reviewed in this paper. These advances represent three broad disciplines of Process Simulation, Forming Processes, and Computer-Aided Measurement Methods. The first development deals with simple and quick computer simulation of 2D sheet forming process without depending on popular finite element analysis methods. An analytical method based on a thin shell theory accounts for bending and unbending effects, and is capable of simulating practical sheet metal forming processes under the plane strain condition. The second area is concerned with innovative methods to improve formability of sheet materials by temperature gradient forming. The drawing limit is increased by such an improved temperature gradient forming process. The third and final area deals with a totally new experimental technique to capture 3D geometry data and measure strain distributions of sheet metal parts using a digital 35mm SLR camera.

• Composites Research
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• 제33권5호
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• pp.302-308
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• 2020

본 연구는 탄소 복합소재를 이용하여 오토클레이브와 진공백(Vacuum Bag Only) 공정으로 소재의 열전도 계수를구하고 경화 거동 모델을 통해 표면부와 내부의 경화 거동을 예측 및 비교하였다. 공정에 따른 열전도 계수의 변화로 인해 내부 온도가 표면부와 차이를 보였다. 오토클레이브 공정의 경우 높은 열전도 계수를 통하여 표면부와 내부의 온도는 거의 일치를 하였으며, 경화 거동 역시 유사하게 진행이 되었다. 하지만, 진공백 공정의 경우 표면부와 내부의 경화 거동이 많은 차이를 보였다. 이 차이는 부품 내부의 품질 및 공기 배출에 영향을 준다. 기계적 물성 차이를 확인하고자 0도 단방향 시편으로 압축시험을 수행하였고, 그 결과 진공백 성형이 조금 낮은 물성을 갖는다는 것을 확인하였다.

• 한국세라믹학회지
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• 제54권6호
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• pp.470-477
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• 2017

Ceramic processing to fabricate 3D complex ceramic structures is crucial for structural, energy, environmental, and biomedical applications. A unique process is ceramic stereolithography, which builds ceramic green objects from CAD files from many thin liquid layers of powder in monomer, which are solidified by polymerization with a UV laser, thereby "writing" the design for each slice. This approach directly writes layers in liquid ceramic suspension and allows one to fabricate ceramic parts and products having more accurate, complex geometries and smooth surfaces. In this paper, both UV curable materials and processes are presented. We focus on the basic material principles associated with free radical polymerization and rheological behavior, cure depth and broadening of cured lines, scattering at ceramic interface and their corresponding simulation. The immediate potentials for ceramic AM to change industry fabrication are also highlighted.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.980-983
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• 2000

The world faces a legacy of serious environmental problems such as exhaustion of natural resources and lack of landfill sites. To address these problems, recycling of materials and products has been proposed, but at present, it is realized only within a few fields. This is because most industrial products consist of various components made of different materials and their recycling are based on the assumption that they can be separated and classified easily, the actual situation however cannot satisfy this assumption. The issue in recycling the components and wastes of used cars, in turn, gives rise to emphasis on the disassembly process. For the efficient disassembly, the component materials and their easy separation as well as the recyclability must be taken into account as early as in the design process. It should be developed an almost perfect design catalogue with existing technologies by analyzing design characteristics, manufacturing, assembly and disassembly processes for major parts and components of automobiles in terms of existing and newly proposed recycling technologies. Also it is essential to provide more technical know-how and application methods that may be helpful to utilize different components and component groups.