• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1101-1104
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• 2004

A brake spider in an irregular shape, which is used as a part in the braking system of a vehicle like a big truck and a trailer, is subjected to a large torque and hence requires both strength and endurance over the brake heat. Manufacture of this product in practice is generally composed of hot forging processes and machining. At the present study, two or more processes were considered for the hot forging. With an initial circular billet, blocker and finisher processes were analyzed using the rigid-plastic finite element method and also in addition to the preforming process. Proper forging processes to manufacture an irregular product without forging defects, which are preforming, blocker and finisher, were discussed and commented upon.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.98-106
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• 1999

In this study cold rolling process for the irregular cross-sectional shape has been investigated. The product analyzed in present study is the steel cutter, which is frequently used to cut the desired shape on leather. Because steel cutter always has a irregular cross-section, after rolling process the workpiece is severely bended to every direction. The bending of the workpiece affects the processed performed after rolling such as heat treatment and grinding, then that of the workpiece becomes more severe. In this study, therefore, to prevent the bending of the workpiece to the left and right sides. rigid-plastic finite element method has been utilized and in order to find optimal roll geometry rapidly, one dimensional equal interval search technique has been also introduced. By using both rigid plastic finite element method and optimum technique, cold rolling process for the irregular cross-sectional shape has been successfully investigated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1097-1100
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• 2004

A rear axle spider in an irregular shape, which is used as a part in the braking system of a vehicle like a big truck and a trailer, is subjected to a large torque and hence requires both strength and endurance over the brake heat. This part should be therefore manufactured in dimensional accuracy. The practical manufacturing process of this irregular product requires the heat treatment process after hot forging and then the cold coining process for the dimensional accuracy. At the present study, the warm coning without the heat treatment process was proposed to employ the residual heat due to the hot forging process. And also the trimming and piercing process was designed using the rigid-plastic finite element method. The mechanical properties were discussed and also commented upon.

• 한국결정성장학회지
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• 제32권1호
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• pp.33-39
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• 2022

3D 프린터 관련 특허가 만료되고 주요 기술이 공개되면서 3D 프린터 가격이 하락하면서 원하는 제품을 쉽게 찾을 수 있는 환경이 조성되고 있다. 특히 가장 저렴한 FDM(Fused Deposition Modeling) 3D 프린터가 다양한 분야에서 사용되고 있다. FDM 방식은 형상을 출력할 때 특정 조건이상에서는 지지대(Support)를 붙여야만 형상의 무너짐 없이 제작이 가능하다. 지지대를 달지 않고 형상을 출력할 때 특정 각도에서 발생하는 불규칙한 표면은 제품에 있어서는 불량이지만 예술과 공예적 측면에서는 또 다른 재미를 느낄 수 있는 요소로 활용될 수 있다고 사료된다. 본 논문에서는 이러한 불규칙한 표면을 얻기 위해 출력에 영향을 줄 수 있는 요인들을 제어하고 출력 각도만 변위요소로 실험하였다. 실험 결과 수직에서 62°~70°의 각도로 프린팅 시 필라멘트가 흘러내리지 않고 불규칙한 표면을 얻을 수 있었다. 또한 인위적으로 불규칙한 표면을 공예적인 제품에 적용해 보았다.

• 한국기계가공학회지
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• 제11권3호
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• pp.104-109
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• 2012

Recently, the deburring process which is last process of manufacture is one of the important process for complete product. The manual deburring process can cause not only higher error rate but also irregular shape and quality of product. Therefore, Shape Guided Automatic Deburring Machine has been developed to resolve the above problems. But the Shape Guided Automatic Deburring Machine have been applied only to produce a circular product. Therefore, this machine is difficult to apply to products of various shapes. To solve this problem, we would like to develop Generalized Shape Guided Automatic Deburring Machine applicable to various shapes. To this end, we have done the modeling and design using CATIA program and have performed machine simulation.

• 한국기계가공학회지
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• 제10권1호
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• pp.16-22
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• 2011

Recently, the deburring process which is last process of manufacture is one of the important process for complete product. The development of shape guided automatic deburring machine is essential because manual deburring process has very irregular quality and higher error rate as well as consider irregular shape radius. In order to develop of shape guided automatic deburring machine, in this study, we conducted 3D design, assembly, machine simulation and structural analysis using CATIA. Also, we conducted to make automatic deburring machine and conducted a performance test.

• 한국정밀공학회지
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• 제15권3호
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• pp.18-23
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• 1998

This paper describes a research work of developing a computer-aided design of blanking and piercing for irregular-shaped sheet metal products. An approach to the CAD system is based on the knowledge-based rules. Knowledge for the CAD system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD with a personal computer and is composed of four main modules, which are input and shape treatment, flat pattern layout, production feasibility check, and strip layout module. Based on knowledge-based rules, the system is designed by considering several factors, such as radius and angle of bend. material and thickness of product, complexities of blank geometry and punch profile, and availability of press. This system is capable of unfolding a formed sheet metal part to give flat pattern and automatically account for the adjustment of bend allowances to match tooling requirements by checking the dimensions and relationships of parts of the folded product. Also this system can carry out a process planning which is obtained from results of irregular shape of product that was successful in production feasibility check module according to flat pattern layout and generate strip layout drawing in graphic forms. The developed system provides its efficiency for flat pattern layout, and strip layout for the irregularly shaped sheet metal products.

• 생약학회지
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• 제26권4호
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• pp.411-418
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• 1995

In order to clarify the originality of several Alisma Rhizomes, we investigated the differences of their morphological, anatomical and physiochemical characteristics. Morphological observation shows the variability of Alisma shape and quality. The diversities in morphological shapes and qualities of tuber were observed among different origins. Chinese product looked like corm shape, but korean's irregular shape. The microscopic observation of korean Alisma revealed the presence of irregular vascular bundle which was scattered transversely and longitudinaly, which was different from that of the rhizome. This facts suggest that the portion of crude drug in Alisma should be the corm rather than the rhizome. In the physicochemical differences, chinese Alisma contains larger amount of mineral elements such as K, Na and Ca than korean Alisma. On the contrary, protein contents in lyophilized powder of aqueous extracts in korean Alisma rhizome was significantly higher than chinese Alisma rhizome. The leaves and stems contained larger amount of Ca and Na than tuber, and may be used as the osmotic diuretics for chinese traditional medicine.

• 한국정밀공학회지
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• 제15권8호
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• pp.174-182
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• 1998

This paper describes a research work of developing a computer-aided design and machining of irregular shaped-sheet metal product for blanking or piercing operation. An approach to the CAD/CAM system is based on the knowledge-based rules. Knowledge for the CAD/CAM system is formulated from plasticity theories, experimental results and the empirical knowledge of field experts. The system has been written in AutoLISP on the AutoCAD and in customer tool kit on the SmartCAM with a personal computer and is composed of nine modules, which are input and shape treatment, flat pattern-layout, production feasibility check, blank-layout, strip-layout, die-layout, data conversion, modelling, and post-processor module. Based on knowledge-based rules, the system is designed by considering several factors, such as material and thickness of product, complexities of blank geometry and punch profile, diameter and material of a wire, and availability of press. This system is capable of generating NC data automatically according to drawings of die-layout module. Results which are carried out in each module will provide efficiencies to the designer and the manufacturer of blanking or piercing die in this field.

• 대한기계학회논문집A
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• 제21권7호
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• pp.1141-1148
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• 1997

In the stamping industry the blank shape to be stamped into a designed shape has been conventionally determined from the try out process by the press engineers. The work needs a lot of time and thus leads a loss of productivity. In this study boundary element method for 2-dimensional potential problem was used to design optimum blank shapes for irregular press forming. Here we assumed that the blank is controlled by blank holder only and material flow at blank holder was under potential flow. The developed PC code for designing the optimum blank shape shows that the blank shapes for optimal drawing can be calculated within a few minute in pentium PC and the calculated shapes agree well with the experiments. However the application of this method is constrained only to the pressed product with flat bottom.