• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.246-251
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• 2000

In the present study, the analysis on heat and fluid flow in the single screw extruder is carried out by simultaneously considering the metering section and the die. The finite difference method and the finite volume method are applied to the metering section and the die, respectively. The zonal method is used to couple the metering section and the die. To investigate the effect of die on the characteristics of heat and fluid flow in the single screw extruder, the pressure back flow is included in the analysis. The screw-tip rotation is also considered by employing the quasi 3-dimensional die model. The present results are compared with the numerical and experimental data available in the literatures.

• 소성∙가공
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• 제16권6호
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• pp.452-456
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• 2007

Cold forging technology of a gear product is being interested in the dimensional accuracy, high stiffness and reduction of stress concentration. Especially it is needed to avoid the damage due to extremely high local pressure. Therefore it is important to reduce the high pressure in die design of cold forging. In this study, single die insert type and splitted die insert type are considered to recognize the notch effects in the die of sprocket forming. The stress concentration has been released at the notch area by the cushion effect in the splitted die insert.

• Elastomers and Composites
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• 제57권4호
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• pp.147-156
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• 2022

In this study, we chose a flat die to optimize a general die geometry. The optimization was aimed at obtaining a uniform velocity distribution across the exit of the die. For the optimization, the input and output design parameters were randomly computed, and response surfaces were generated to obtain statistical data for the minimum and maximum sensitivities computed during optimization. Subsequently, object functions with constraints were numerically computed to obtain the minimum errors in the velocity difference (i.e., variable "Outp" in this study). Finally, we obtained the candidate optimized dataset. Note that the current numerical computations were simultaneously conducted for an entire extruder, i.e., screw plus die. The numerical outlet velocity distributions in the modified die geometry tended to be much more uniform than the conventional distributions in the current optimization processes for this specific flat die.

• 마이크로전자및패키징학회지
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• 제19권4호
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• pp.45-50
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• 2012

A family of multi-die DRAM packages was developed that incorporate the full functionality of an SODIMM into a single package. Using a common ball assignment analogous to the edge connector of an SODIMM, a broad range of memory types and assembly structures are supported in this new package. In particular DDR3U, LPDDR3 and DDR4RS are all supported. The center-bonded DRAM use face-down wirebond assembly, while the peripherybonded LPDDR3 use the face-up configuration. Flip chip assembly as well as TSV stacked memory is also supported in this new technology. For the center-bonded devices (DDR3, DDR4 and LPDDR3 ${\times}16$ die) and for the face up wirebonded ${\times}32$ LPDDR3 devices, a simple manufacturing flow is used: all die are placed on the strip in a single machine insertion and are sourced from a single wafer. Wirebonding is also a single insertion operation: all die on a strip are wirebonded at the same time. Because the locations of the power signals is unchanged for these different types of memories, a single consolidated set of test hardware can be used for testing and burn-in for all three memory types.

• 대한기계학회논문집A
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• 제21권7호
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• pp.1073-1080
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• 1997

The stage 1 compaction behavior of tool steel powder under die pressing was studied. The friction effects between the powder and the die wall under different die pressing modes were also investigated. The elastoplastic constitutive equations based on the yield functions by Fleck et al. and by Shima and Oyane were implemented into a finite element program to simulate die compaction processes. Finite element calculations were compared with experimental data for densification and density distribution of tool steel powder under single and double action die pressing. Finite element calculations using the yield function by Fleck et al. agreed better with experimental data than by Shima and Oyane.

• 소성∙가공
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• 제11권4호
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• pp.363-370
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• 2002

In this study, an optimal design technique was investigated for determining appropriate dimensions of components of the die set used in the extrusion process. For this, an axi-symmetric elastic finite element program for the analysis of deformation of the shrink fitted die set was developed with the Lagrange multiplier method to implement the constraint condition of shrink fit of stress ring. By coupling the rigid-viscoplastic analysis of extrusion process by CAMPform and elastic analysis of the die set, the optimization study was made by employing optimization program DOT. Considering the various assembly conditions, optimal design was determined for a single stress ring case. It is construed that the proposed design method can be beneficial for improving the tool life of cold extrusion die set at practice.

• 한국산학기술학회논문지
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• 제12권2호
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• pp.588-593
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• 2011

프로그레시브 노칭과 포밍금형에 있어서 박판성형해석에 의한 사전 분석은 제품을 양산하는데 꼭 거쳐야 하는 필수과정이다. 본 논문에서 연구한 Ez5는 일본 S 자동차의 미국 현지 공장에서 발주한 수출 금형을 가지고 스트립 레이아웃 설계에 관한 것을 연구한 것이다. 광폭 1열 1개 뽑기의 편측캐리어를 단 배열로 블랭크 레이아웃을 최적화하여 13개 공정으로 된 스트립 레이아웃설계를 완성하였다. 이런 형태의 금형수주는 앞으로 동시 다발적이고, 매우 빈번히 인터넷 공간상에서 발생할 것이며 금형에 대한 기술력을 갖춘 업체는 이러한 방식에 대응할 준비를 갖추어야 할 것이다.

• 한국결정성장학회지
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• 제18권1호
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• pp.1-4
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• 2008

The growth of composite-structured Nd:$GdVO_4$ single crystal rods by the double die EFG method is reported. Two crucibles are combined with an outer and inner die for ascending of different melt. The composite-structured Nd:$GdVO_4$ single crystal rods with a length of 50 mm and an outer diameter of 5 mm including of inner Nd-doped core region with diameter 3 mm were grown successfully. Nd distribution in the, radial direction has graded profile from result of EPMA. Absorption coefficient in the core region at 808 nm was $42cm^{-1}$. Finally, we demonstrated the laser oscillation using our composite crystal and 2-W output was obtained.

• 한국기계가공학회지
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• 제11권6호
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• pp.9-15
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• 2012

Vibrational film has been more employed in ear-phones or small type of speakers along with a wide use of portable multi-media equipments such as MP3 and MP4. However, the current hand work production process of diaphragms is inefficient. In this study, a die-and-mold and a single production forming machine are developed, and they result in a multi-production forming machine. The multi-production forming machine consists primarily of a film feeding unit and an unwinding unit. A vacuum suction device provides the film feeding unit, while the unwinding unit is obtained using an appropriate damper. The advantage of the developed single production forming machine is shown according to a proper voice test.

• 대한기계학회논문집A
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• 제20권6호
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• pp.1893-1902
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• 1996

Densification behavior of 316L stainless steel power under die pressing was studied. The efects of friction between the powder and die wall under different die pressing modes were also investigated. The elastoplastic constitutive equations based on the yield functions of Fleck-Gurson and of Shima and Oyane were implemented into finite element program(ABAQUS) to simulate die compaction processes. The finite element results were compared with experimental data for 316L stainless steel powder under die pressing.