• 소성∙가공
• /
• 제10권7호
• /
• pp.551-557
• /
• 2001

In the present study, several design parameters of the flat-die extrusion process are investigated using the finite element method. The effects of the location of an extrusion profile, arrangement of multiple extrusion profiles, and the design of various die land have been investigated through the analysis. Several numerical examples of flat-die extrusion of such as C-section, multiple U-shape, and a window guide section, are analyzed. From the comparative study, the effect of design parameters is investigated. In each example, comparing the velocity distribution with that of the original design, it has been shown that the design modification affords more uniform distribution.

• 한국재료학회지
• /
• 제14권3호
• /
• pp.168-174
• /
• 2004

The aim of this study is to investigate the effect of process conditions on the microstructual changes and mechanical properties of large 7175 aluminum die forgings. The cast billets of 370 and 720 mm in diameter were homogenized and die forged after direct chill casting. The size and volume fraction of second phase particles in 720 mm billet were larger than those of 370 mm billet. The interdendritic sites containing the second phase particles was considered to be a crack initiation region in the process of cold upsetting. The tensile and yield strength of die forged specimens of 720 mm billet in the direction of Land L T were higher than those of 370 mm billet. However, the tensile strength of these specimens were 5 to 10% lower than that of American military specification. The plane strain fracture toughness of die forged specimens of 370 mm cast billet showed almost the same level of 720 mm billet, which was die forged after free forging.

• 한국정밀공학회지
• /
• 제20권1호
• /
• pp.135-143
• /
• 2003

This study presents development of a automatic design software for process and die design of hot extrusion of aluminium alloys through square dies. The design of extrusion dies is still an art rather than a science with increasing complexity of shape and thinness of section. Therefore, most of the die design is still dependent on personal judgement, intuition and experience. The objective of this study is to develop a software system which includes a design rule extracted from literatures and experts in the extrusion industry. The developed system is effectively used to design extrusion processes and dies with reduced lead time and trial extrusion.

• 산업식품공학
• /
• 제15권2호
• /
• pp.148-154
• /
• 2011

사출구 구조가 압출성형의 목적변수인 팽화특성에 영향을 미치는지 알아보기 위하여 사출구의 기하학적 구조를 사출구상수로 산출하여 사출구상수와 수분함량에 따른 팽화특성을 비롯한 비기계적 에너지 투입량, 수분용해지수, 수분흡착지수를 분석하였다. 압출성형 공정변수는 수분함량(20, 25%), 사출구멍의 길이와 직경비(L/D 0.67, 1.67, 2.67), 내벽에서 좁아지는 각(57, $95^{\circ}$)이였다. 비기계적 에너지 투입량은 수분함량 20%, 사출구상수 2.23E-10 $m^3$에서 가장 높은 값을 나타내었다. 수분함량 20%에서 사출구상수가 증가하면, 직경팽화지수와 체적팽화지수는 증가하였다. 한편 수분함량 25%에서 직경팽화지수와 체적팽화지수는 사출구상수의 영향을 받지 않았다. 또한 길이팽화지수는 수분함량이 20%에서 25%로 증가할 때 증가하였으며 직경팽화지수와 음의 상관관계를 나타내었다. 수분흡착지수와 수분용해지수는 사출구상수에 영향을 받지 않았다.

• 의료법학
• /
• 제10권2호
• /
• pp.183-201
• /
• 2009

Im Allgemeinen auch psychische Patienten k$\ddot{o}$nnen sich daruber selbst entscheiden, $\ddot{a}$rztliche Behandlung zu nehmen und ins Krankenhaus aufgenommen zu werden. Im S$\ddot{u}$dkorea bei der zwangsweisen Unterbringung wird kein KBGB des privatlichen Rechts, sondern Gesetz $\ddot{u}$ber psychisch Gesundheitspflege des $\ddot{o}$ffentlichen Rechts vorz$\ddot{u}$glich verwandt. Aber das noch kann ein selbst Bestimmungsrecht von der psychischen Patient verletzen. Im Deutschland regelt BGB $\S$ 1906 Zwangsunterbringung der psychische Patienten, die Gef$\ddot{a}$hr des Selbstmord oder der Eigengef$\ddot{a}$hrdung haben. Au$\ss$erdemhat jedes Land eigen Gesetz $\ddot{u}$ber psychischen Kranken, das $\ddot{o}$ffentliche Vorschrift f$\ddot{u}$r Zwangsunterbringung regelt. Im Fall der Zwangsunterbringung im Deutschland BGB $\S$ 1906 wird prim$\ddot{a}$rer als $\ddot{o}$ffentlich Rechts verwandt, um die Selbstbestimmungsrecht der Patienten zu unterstutzen. Auch im Korea KBGB (koreanisches B$\ddot{u}$rgerliches Gesetzbuch) Ver$\ddot{a}$nderungen f$\ddot{u}$r die Einf$\ddot{u}$hrung des Betreuungsrechts, die sich mit der Zwangsunterbringung befassen, sollten diskutiert werden, damit die Selbstbestimmung sch$\ddot{a}$tzen.

• 소성∙가공
• /
• 제13권8호
• /
• pp.723-730
• /
• 2004

This paper describes the analysis of extrusion process and integrity for a condenser tube which is a component of the heat exchanger in automobile and all conditioning apparatus. Recently, according to the development of analysis method using the computer, the numerical simulation have been applied to the 3-dimensional hot extrusion process with complex section area of the non-steady statement and then results of the analysis have been applied to optimal die design and process design. In this paper, firstly, the die design was performed for a condenser tube with a multi-hole section and the rigid-plasticity FE analysis performed of extrusion process. Secondly, we estimated metal flow of billet, extrusion load, welding pressure in chamber etc. and evaluated the pressure and elastic strain of the die land and mandrel tooth profile through a stress analysis of the die. Finally, the extrusion test was performed to estimate the validity of FE analysis. This paper confirmed that the designed extrusion die of the research is satisfactorily designed fur integrity of condenser tube.

• 한국산학기술학회논문지
• /
• 제4권1호
• /
• pp.36-41
• /
• 2003

열간단조 밀폐금형의 수명연장을 위한 빌릿의 소성변형 유동해석을 유한 요소법에 의하여 실시한 결과 임프레션 형상에 대한 수정설계를 수행하였고, 임프레션 표면 마멸부위의 보수방법을 육성용접에 의한 방법으로 금형을 재생하여 사용한 결과 개발 전의 3,0(H개 생산에서 개발 후 5,000개 양산되었을 때 임프레션 표면을 관찰하였더니 3,000개 정도에서 나타났던 마멸보다 얕은 마멸이 나타났다.

• 한국정밀공학회지
• /
• 제16권11호
• /
• pp.116-121
• /
• 1999

Since the material flow near the die part in CONFORM (Continuous Extrusion Forming) process is similar to that of side-extrusion, the side-extrusion model of tube shaped aluminum profiles was studied for the die design in CONFORM process. In this paper, the effects of process parameters in the side -extrusion through a two-hole die face, such as material flow, height and thickness of the tube, velocities of punch and lengths of bearing land were investigated using UBET program and DEFORM commercial FEM code. The optimum lengths of the bearing lands and punch velocities for obtaining the straight shape products required were determined.

• 한국정밀공학회지
• /
• 제22권12호
• /
• pp.93-99
• /
• 2005

In this work, computer-aided process design is carried out to develop an optimal preform of a pressure vessel. Knowledge-based rules are employed to design the preform, and they are formulated using the handbooks of plasticity theories. In the FE-analysis, a commercial finite element code, ABAQUS was employed. Axisymmetric deep drawing of a hemisphere-bottomed cup has been analyzed fur various combinations of die design parameters. The length of the land of die, the clearance between punch and die and the clearance between the blank holder and die are optimized to minimize the forming load. The results of the simulations are verified with the experiments which are scaled down to one tenth of the actual size.

• Design & Manufacturing
• /
• 제10권3호
• /
• pp.1-7
• /
• 2016

In the semiconductor industry the memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. After injection molding process the side gates were needed to remove for further assembly process. ln this study, the cold press cutting process was applied to remove the gates. For design of punch and die, the cold press cutting analysis was implemented by$DEFORM-2D^{TM}$ ln consideration of the simulation results, an adequate punch and die was designed and made for the cutting unit. In order to verify the performance of cutting process, the roughness of cutting section of the part was measured and was satisfied in requirement.