• 한국기계가공학회지
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• 제12권5호
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• pp.86-93
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• 2013

Main function of the Press forming Machine is the forming for plates. The head of the Press forming machine consist of several parts. It was named Press forming-contraction and Press forming_expansion according to formability of plates. Aluminium and Titanum plates are forming by using the Press forming machine. In this study, we analyzed sheet metal forming including plastic deformation and the contact pressure in the bearing. Finite element analysis results of Press forming-contraction and Press forming_expansion show the similar results of the actual specimen plates and the bearing contact pressures show the acceptable level of stress in both aluminum and titanium specimens.

• 소성∙가공
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• 제25권2호
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• pp.116-123
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• 2016

Press-brake bending is used to shape flat and thick plates into a targeted circular configuration without excessive localized thinning or thickening. A brake bending press called 'a knife press bending apparatus' has been widely adopted to manufacture thick, large and long pipe from initially thick plate. Submerged Arc Welded (SAW) pipes are also produced by employing press-brake bending. These pipes are mainly used for oil, natural gas and water pipelines. The principal process variables for press-brake bending can be summarized as stroke of the press-brake knife, the distance between both roll in the lower die, and the feeding length of the plate. Many combinations of these process variables are available, thus various pipe diameters can be realized. In the current study, a series of repetitive numerical simulations by feeding a thick plate with initial thickness of 25.4mm were conducted with the consideration of elastic recovery. Furthermore, an index for SAW pipe production is proposed which can be widely used in industry.

• 소성∙가공
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• 제25권4호
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• pp.268-274
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• 2016

In the automotive seat industry, the use of a fine blanking press is important for manufacturing of high precision products. Among them, a gear part which is a main component of an automotive seat recliner is generally manufactured by fine blanking press. However, the use of conventional mechanical press has been increasing in manufacture of gear part because of low productivity of fine blanking press. In this study, new forming process is suggested to fabricate the gear part with high precision by using mechanical press. The effect of flow restriction die (FRD) which has the restriction of blank edge on dimensional accuracy is investigated by FE-analysis. FE-analysis results for different conditions of FRD indicated that FRD has high dimensional accuracy with the lowest roll-over and the highest perpendicularity of gear part. After application to fabrication of the gear part using mechanical press, the measured dimensional characteristic was compared with the required specification of final product. In addition, results of the performance test showed that the product fabricated by developed process satisfied the required strength and durability. The results show that the suggested forming process by using FRD and mechanical press can replace fine blanking on the viewpoint of dimensional accuracy and productivity.

• Journal of Biosystems Engineering
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• 제10권2호
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• pp.47-54
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• 1985

Performance of a screw press was investigated experimentally with soybeans of various temperatures in order to find out a proper temperature of soybean to extract the oil by the mechanical method. Crude oil extracted by the screw press was chemically analyzed to determine a level of processing the oil for the oil to be used as a fuel for a compression ignition engine. The crude oil was degummed and dried by a plant type laboratory experimental setup to decide whether the processes are effective to improve quality of the oil as a fuel. The degummed oil and the degummed and dried oil were also chemically analyzed and were compared with the crude oil and the commercially degummed and dried soybean oil. The results are as follows: 1. In extraction of soybean oil by a screw press, heating soybeans is effective to increase oil production and to decrease energy consumption of the press. A proper temperature of soybean to extract the oil by the press was determined as about $50^{\circ}C$. 2. Soybean oil production and electric energy consumption of the press are about 83 ml and 58 Wh per 1 kg of soybeans heated to about $50^{\circ}C$, respectively. 3. The quality of crude oil produced by the press is similar to that of the commercially degummed and dried oil. The crude oil does not need to be degummed or dried for use as an engine fuel.

• 한국주조공학회지
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• 제42권6호
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• pp.358-368
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• 2022

본 연구에서는 다양한 생압고철의 충전 거동을 시각화 시뮬레이션하였고, 초기 장입 단계가 종료된 후, 충전 상태를 정량적으로 비교하였다. 300mm 정육면체 생압고철, 맞춤형 정육면체 생압고철, 맞춤형 팔각기둥 생압고철, 맞춤형 원기둥 생압고철을 비교 대상으로 하였다. 맞춤형 생압고철의 경우, 1, 1.5, 2, 3, 4, 5, 6t/h 용량의 용해로에 맞춤형 크기로 설계하였다. 초기 장입 개수, 추가 장입 중량 백분율, 충전 밀도, 틈새 공간 부피 백분율 등 충전 상태를 비교 평가하였다.

• 한국콘텐츠학회논문지
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• 제11권1호
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• pp.340-349
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• 2011

이 연구는 4P(Police-Press-Politics-Public) 모델의 분석을 통해 언론과 경찰의 바람직한 관계 정립을 위한 정책적 제언을 목적으로 한다. Jean-Louis Loubet Del Bayle은 4가지 주체인 경찰, 언론, 대중, 정치의 관계에 관하여 정보의 교류와 흐름, 권력관계, 정당성 관계라는 3가지 측면에서 이들 간의 관계 모델을 제시하고 있다. 모델 분석을 통해 알 수 있는 것은 언론과 경찰은 국민과 정치라는 외부 주체와의 관계에서 정당성(Legitimacy)을 부여받고 그 정당성을 바탕으로 정보를 입수하고 상대방에 대한 통제 권한을 행사한다는 것이다. 이렇듯 각자의 사회적 기능과 외부환경과의 관계는 경찰과 언론의 관계를 민감하고 복잡하게 만드는 근본 이유가 된다. 4P모델의 분석을 통해 알 수 있는 것은 언론과 경찰의 균형적 관계 정립은 두 주체의 사회적 기능을 보장하고 정당성 확보의 공통 경로인 국민들의 이익으로 귀결된다는 것이다. 또한, 경찰은 언론과의 균형적 관계 형성을 통해 사회변화의 적응성을 높여 경찰행정발전의 영속성을 확보할 수 있다는 것이다. 그리고 경찰과 언론의 균형적 관계를 위해서는 두 주체에게 공통적으로 적용되는 실질적인 '보도 가이드라인'이 마련되어야 하고, 경찰로서는 언론에 대한 사회적 기능의 이해와 관계 개선을 위해 전문적인 인력으로 구성된 언론 담당 부서를 설치해야 한다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.190-193
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• 2008

Thick pipes which have large thickness have been used in fields of ocean and industrial plants, and for oil pipelines, water pipes and pipe arrangement. In manufacture of the pipes, roll bending process has been used mostly. However, studies on the pipe forming processes using brake press have been performed in recent days. Normally, the brake press has high aspect ratio, so analysis of structural integrity should be conducted. In this study, the evaluation of structural integrity of the brake bending press was carried out for thick pipe forming process.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2002년도 학술대회 논문집
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• pp.101-104
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• 2002

The influences of the powder packing density on the Bi-2223/Ag tape have been investigated. For packing powder, both method of uniaxial press and packed rod form made by cold isostatic press(CIP) have been applied. As the pressure of cold isostatic press(CIP) is increased, fill factor and critical current (Ic) of Bi-2223/Ag tape is increased. At a pressure of 2000kgf/cm$^2$, fill factor reach ∼3l% and this sample has the engineering current density(Je) value of ∼8.5kA/cm$^2$(Ic ∼77A, Jc ∼ 30kA/cm$^2$). The tape sample packed by uniaxial press method shows more sawsaging effect than the sample processed by cold isostatic press(CIP), resulting from inhomogity of powder distribution produced by the process of uniaxial press.

• 한국생산제조학회지
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• 제22권3호
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• pp.356-363
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• 2013

Mechanical molding press which is used for transformation process during semiconductor manufacturing process has structural deformations by pressure. If these deformations have over limit range, life of the press itself can be reduced and it will be exerted on a bad effect for quality of the semiconductor. In this research, the main plates and links of a press are analyzed in relation to the structural deformations caused by pressure excluding thermal deformations. After modifying the modeling, the analysis is performed again to determine optimal design of the press, and this design is introduced to ensure that most of the stresses on the main plates are within safe allowable limits. As a result, an optimal design method for the structure is investigated to produce the desired pressure even when the size of the main structure is minimized.

• 한국자동차공학회논문집
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• 제2권1호
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• pp.73-83
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• 1994

Press formabilities of aluminum sheets for automobile body were investigated. Plane strain stretching test (called RIST-PSST), cupping test and U bending test were performed to assess the press formability of aluminum sheets respectively. The results showed that aluminum sheets are generally inferior to cold-rolled steel sheet of deep drawing quality (CSP3N) in press formability. The limiting punch height (LPH) and limiting plane strain (FLCo) of aluminum sheets are 50%-70% level compared to that of CSP3N. Moreover, the limiting drawing ratios(LDR) of aluminum sheets are ranged between 1.95 and 2.1. The poor press formability of aluminum sheets is responsible for low values of total elongation and plastic anisotropy parameter in tensile characteristic. The shape fixability of aluminum sheets evaluated in U bending test is very poor due to its low elastic modulus compared to CSP3N.