• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 압출 및 인발 심포지엄
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• pp.79-82
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• 1999

This paper presents a study of cold combined forward-backward extrusion product. The case of product with thin wall in piercing process occur defects of deformation and breakdown during piercing process and the center web of product with thin thickness cause flow defect. Such defect is made by the difference of material flow. Methods of the material flow control in the two directions and forming process to remove this flow defect is proposed. The effectiveness of the proposed methods is examined by comparison experiment and finite element simulation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.713-716
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• 2002

The dimensional accuracy of the cold forged products is strongly dependent on the elastic behavior of the die. The elastic deformation of the die is continuously changed during the process. Therefore, it is needed to measure the deformation of die. Strain gauges are used to measure the elastic strains in the die during cold backward extrusion process. The strain gauges are attached on the die surface and embedded at the interface between the die insert and the stress ring. In order to compare the results with the FE-analysis, the rigid-plastic FE-analysis of cold backward extrusion process using DEFORM-3D has been performed, and the analysis of elastic deformation of the die has been done by using ANSYS with non-linear contact.

• 한국식품영양과학회지
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• 제44권8호
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• pp.1212-1218
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• 2015

본 연구는 저온 및 재래식 압출성형 공정에 따른 쌀 야채류 압출성형의 항산화 활성에 대해 분석하였다. 압출성형 조건은 수분 함량 25%, 스크루 회전속도 150 rpm으로 고정하였다. 저온 압출성형 조건은 사출구 온도 $80^{\circ}C$, $CO_2$ 주입량 300 mL/min, 재래식 압출성형은 사출구 온도 $140^{\circ}C$, $CO_2$ 0 mL/min으로 조절하였다. 원료는 쌀 분말에 단호박, 토마토, 딸기 및 녹차 분말을 각각 10%씩 혼합하여 사용하였다. 단호박 및 토마토 첨가한 압출성형물의 DPPH 라디칼 소거능은 저온 압출성형 공정보다 재래식 압출성형 공정에서 더 높았다. 단호박, 토마토 및 딸기를 첨가한 압출성형물은 압출성형 후 총 페놀 함량이 증가하였으며, 저온 압출성형물보다 재래식 압출성형물에서 총 페놀 함량이 다소 높았다. 총 플라보노이드 함량은 녹차를 첨가한 재래식 압출성형물이 18.82 mg/g으로 가장 높았다. 압출성형 후 단호박을 첨가한 압출성형물의 총 카로티노이드 함량은 낮아졌으나 토마토 압출성형물은 증가하였다. 토마토 압출성형물의 라이코펜 함량은 압출성형 후 증가하였으며, 재래식 압출성형에서 더 높았다. 딸기 압출성형물의 안토시아닌 함량은 저온 압출성형보다 재래식 압출성형 공정에서 높았다. 압출성형 후 녹차 압출성형물의 총 클로로필 함량은 감소하였으며 클로로필 a, b 및 총 클로로필은 저온 및 재래식 공정에 따른 유의적인 차이는 없었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.931-932
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• 2012

• 한국정밀공학회지
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• 제32권11호
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• pp.977-982
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• 2015

This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from $30^{\circ}$ to $60^{\circ}$, also by finite element analysis. We suggest suitable tool entrance angles.

• 한국식품영양과학회지
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• 제33권5호
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• pp.899-904
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• 2004

압출성형공법을 이용한 수삼의 전처리를 통한 추출수율의 향상과 최적조건에서 열수 추출한 인삼추출액의 첨가량을 달리하여 저온압출공정으로 제조한 구형과립의 입자분포, 마모율, 용적밀도, 진동밀도, 압축지수와 용출패턴을 결정하였다. 열수추출수율에서 수삼을 압출성형할 때 수분함량이 가장 유의적으로 영향을 미쳤다. 수분함량의 감소와 함께 스크류 회전속도가 증가할수록 압출성형 수삼의 추출수율이 크게 증가하였다. 추출수율이 최대가 되는 압출성형 공정변수는 수분함량 15%, 스크류 회전속도 250 rpm, 사출구 부위온도 13$0^{\circ}C$였다. 동일한 추출조건에서 15개 압출성형 수삼 시료의 평균 추출수율(43.5%)은 홍삼(38.3%)과 백삼(29.0%) 추출수율과 비교하여 크게 향상되었다. 저온압출공정으로 압출성형 수삼농축액(고형분함량 59.2%)의 농도를 5, 20, 30, 40, 50, 60%로 각각 증류수에 희석한 용액 200 mL과 200 g 미세결정 셀룰로오즈를 이용하여 과립화시킬 수 있는 압출성형 수삼추출액의 최대 농도는 60%였으며 추출액의 증가와 함께 입자수율의 증가, 마모율의 감소, 압출지수의 감소 등으로 입자의 물리적 특성은 구형과립을 젤라틴 캡슐에 포장하여 제품화할 수 있었다. 또한 압출성형 수삼 추출액을 포함한 구형과립으로부터 농축액 성분이 10분 이내에 쉽게 용출되므로 구형과립은 젤라틴 캡슐에 적합하다는 결론을 내릴 수가 있었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.403-406
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• 2006

Internal spline forming using a thin and long tube can cause the buckling and folding during the forming process. In the study, we proposed two different extrusion processes, and we performed the analysis in order to obtain the optimal process according to the length of land part. Using the rigid-plastic finite element simulation, the proposed processes have been compared by checking the deformed shape and stroke-road relation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.266-269
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• 2005

The effect of exit temperature on the thickness of recrystallization layer during Al extrusion process was investigated. The recrystallization layer of an extruded Al alloy is an important feature of the product in a wide range of applications, particularly those within the automotive industry. The thicker recrystallized layer in the Al alloys can give rise to a number of problems including reduced fatigue resistance and orange peel during cold forming. But the interaction of extrusion process variables with the thickness of recrystallization layer is poorly understood, and there is limited information available regarding the role of the main hot extrusion variables. Using the 3650 US ton extrusion press, this paper describes the effect of the main process variables such as billet temperature, ram speed, and exit temperature on the thickness of recrystallization layer for the A6XXX Al alloy.

• 소성∙가공
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• 제13권7호
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• pp.623-628
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• 2004

This paper is concerned with pressure welding, which has been known as a main bonding mechanism during the cold and warm forming such as clad extrusion or bundle extrusion/drawing. Bonding characteristics between the Cu and Al plates by pressure welding are investigated focusing on the weak bonding. Experiments are performed at the cold and warm temperatures ranging from the room temperature to $200^{\circ}C$. The important factors examined in this work are the welding pressure, pressure holding time, surface roughness, and temperature. A bonding map, which can identify the bonding criterion with a weak bonding strength of IMPa , is proposed in terms of welding pressure and surface roughness fur the cold and warm temperature ranges.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 추계학술대회논문집
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• pp.174-184
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• 1996

Two methods for cold extrusion processes to produce an axisymmetric steel gear blank are investigated for comparing each other. The "classical" forming method consisting of four operations is selected first to be simulated using the rigid-plastic finite element method and uses single-die presses. The other using a fully automated transfer headers can produce the final part without interannealing. The final products must be checked at the design criteria such as area reduction, the extrusion ratio and punch diameter to depth ratio, especially punch buckling by simulations. FEM analysis is performed mainly for strain distribution, both process sequences are proved to have proper charicteristics suitable for each production method in terms of maximum load. Those simulation results will provide good design criteria in the future work to advance the manufacturing process.