• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.374-377
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• 2008

Magnesium alloy sheets are usually formed at temperatures between $150^{\circ}C$and $300^{\circ}C$ because of their poor formability at room temperature. In the present study, the formability of AZ31B magnesium alloy sheets was investigated by the analytical and experimental approaches. First, tensile tests and the limit dome height test were carried out at elevated temperatures to get the mechanical properties and forming limit diagram, respectively. And then deep drawing of cross shaped die was tried to get the minimum corner radius and forming limit at specific temperature. Blank shape, punch velocity, minimum corner radius, fillet size, etc, were determined by finite element analysis physical try-outs. Especially, optimum punch and die temperature were suggested through the temperature-deformation analysis using Pam-stamp.

• 한국정밀공학회지
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• 제13권5호
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• pp.53-59
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• 1996

Warm deep drawing of single-action dies using local heating has appeared to be an alternative attractive production method of multi-operation die sets generally used at room temperature in deep drawing of rectangular cup. Uniaxial tensile tests and deep drawing tests of various materials are carried out and the effect of temperature on tensile properties and drawability are examined at temperatures up to 200 .deg. C under three kinds of lubricants of teflon film, vinyl film and drawing oil. Good formability is achieved when punch and die temperature were differentiated intentionally in order to get large tensile strength(TS) at punch shoulder protion and small TS at die side. Throughout the experiments, it has been shown that the limiting drawing height of STS316L was increased with heating die and blank holder at 100 .deg. C, but that of STS430 wasn't. When vinyl or teflon film was attached on the plates, the drawability was increased considerably.

• 소성∙가공
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• 제12권3호
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• pp.214-220
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• 2003

In the case of hollow cylinder extrusion using porthole die, the effects of extrusion parameters-temperature, the speed of extrusion, the shape of the die and mandrel-on metal flow in porthole die extrusion of aluminum have been investigated. There have been few studies about condenser tube extruded by porthole die. This study was designed to evaluate metal flow, welding pressure, extrusion load, tendency of mandrel deflection according to variation of chamber length in porthole die. The welding chamber height in condenser tube was calculated by using finite element method. Forming analysis results for condenser tube would provide useful information for the optimal design of porthole die.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문집
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• pp.138-144
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• 1996

In square die extrusion, flow guide and ide land play important roles for controlling the metal flow in die design. In the present work, the flow guide and the die land are considered for the die construction. Based on ALE description , rigid-viscoplastic finite element analysid is carried out to assess the effects of process and die design parameters. The thermal state affects greatly the product quality in hot extrusion. in the present work, the temperature distribution is also analyzed in theframwork of rigid-viscoplastic finite element computation. As a computational example, hot square die extrusion with flow guide and die land has been analyzed for the profile of a H section.

• 소성∙가공
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• 제9권4호
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• pp.413-420
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• 2000

In the die casting process, the flow of liquid metal has significant influence on the quality of casting products and die life. For the optimal process design of front housing part of aircon compressor, various analyses were performed in this study by using computer simulation code, MAGMAsoft. The simulation has been focused on the molten metal behaviors during the filling and solidification stages for the sound casting products. Two cases of casting design that have different types of gating system are considered in the analysis. The potential sites where the casting defects may occur is examined by computer simulation and an improved design process is proposed. Also the effect of partial squeeze on the quality of casting products is considered and the optimal time lag after filling process is determined. For the die-stability, the effect of operational parameters such as die temperature, heat cycle and spot cooling on the die life has also been analyzed.

• 한국식품영양과학회지
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• 제45권8호
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• pp.1170-1176
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• 2016

수분 함량과 사출구 온도, 스크루 회전속도가 분리대두단백의 조직화 및 물리적 특성에 미치는 영향을 분석하였다. 압출성형 조건은 스크루 회전속도를 250 rpm으로 고정하고 수분 함량과 사출구 온도를 20, 25%와 120, 130, $140^{\circ}C$로 조절하였다. 또 다른 압출성형은 수분 함량과 사출구 온도를 30%와 $140^{\circ}C$로 고정하고 스크루 회전속도를 150, 200, 250, 300, 330 rpm으로 조절하였다. 사출구 온도가 $120^{\circ}C$에서 $140^{\circ}C$로 증가함에 따라 비기계적 에너지 투입량은 감소하였으며, 스크루 회전속도가 150 rpm에서 330 rpm으로 증가할수록 비기계적 에너지 투입량은 증가하였다. 사출구 온도가 증가하고 수분 함량이 감소할수록 직경팽화율과 비 길이는 증가하였으며, 밀도는 수분 함량 20%에서 유의적인 차이를 보이지 않았다. 사출구 온도가 증가하고 수분 함량이 감소할수록 기공형성이 증가하여 파괴력이 감소하였으며 사출구 온도 $140^{\circ}C$, 수분 함량 20%에서 $2.07E+04N/m^2$로 가장 낮은 값을 보였다. 수분 함량이 25%에서 20%로 감소하면서 갈변으로 인해 명도가 감소하고 적색도와 황색도는 증가하는 경향을 보였으며 총 색도차는 증가하였다. 스크루 회전속도가 150 rpm에서 330 rpm으로 증가할수록 총 색도차가 증가하였다. 조직잔사지수는 사출구 온도가 증가하고 수분 함량이 낮을수록 증가하였으며, 사출구 온도 $140^{\circ}C$, 수분 함량 20%에서 $26.21{\pm}4.28%$로 가장 높은 값을 보였다. 조직잔사지수는 사출구 온도보다 수분 함량의 영향이 컸다. 사출구 온도가 $120^{\circ}C$에서 $140^{\circ}C$로 증가하고 수분 함량이 25%에서 20%로 감소할수록 수용성 질소지수는 증가하였으며 수분 함량 20%, 사출구 온도 $140^{\circ}C$에서 $7.88{\pm}0.47%$로 가장 높은 값을 보였다. 스크루 회전속도가 330 rpm에서 150 rpm으로 감소함에 따라 수용성 질소지수는 감소하였으며 150 rpm에서 $2.83{\pm}0.51%$로 가장 낮은 값을 보였다. 본 연구를 통하여 수분 함량이 사출구 온도보다 조직화에 더 큰 영향을 주는 것을 알 수 있었다.

• 대한기계학회논문집A
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• 제36권7호
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• pp.723-730
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• 2012

상온의 인발공정에서 소재는 인발다이를 통과하면서 직경이 줄어들고 길이가 늘어난다. 인발다이와 소재가 접촉한 면에서의 압력과 미끄럼 운동에 의해 소재에는 탄성회복, 인발 다이에는 마찰과 마모가 생긴다. 또한, 소재의 변형 및 마찰열로 인해 소재와 다이의 온도가 상승하며 이로 인해 지정된 다이 내경으로 제품이 가공되기 어려우며 소재의 선경은 지정된 직경 또는 다이 내경과 다르게 된다. 본 논문에서는 다이의 온도분포를 고려하여 소재의 탄성회복, 다이의 탄성변형, 그리고 다이와 소재의 열변형이 인발제품의 선경변화에 미치는 영향을 정량적으로 분석하였다. 네 가지 요인 중에서 소재의 탄성회복의 영향이 선경변화량의 대부분을 차지함을 확인하였다. 선경변화에 영향을 주는 인자들을 고려하여 지정된 치수와 차이를 주지 않는 초기 다이를 설계하였고, 설계된 초기 다이를 이용하여 지정된 치수의 인발제품을 얻을 수 있었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 추계학술대회논문집
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• pp.226-229
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• 2004

The temperature difference between die and workpiece has been frequently caused to various surface defects. The distribution and change for the temperature of forged part should be analyzed to prevent the generation of various defects related with the temperature. The surface temperature changes were mainly affected by the interface heat transfer coefficient. Therefore, the coefficient is necessary to predict the temperature changes of die and workpiece. The temperature calculated by FEM result might be well compared with the measured temperature. However, it is impossible to measure directly the temperature distribution of forged part. Therefore, the comparisons between measured temperature and predicted values are preformed by the microstructure in various temperature. Since the differences of microstructure could be obvious, the temperature criteria is set near by the incipient melting temperature. The predicted temperatures are well coincided with the measured values.

• ETRI Journal
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• 제36권4호
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• pp.635-642
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• 2014

Three-dimensional integrated circuits (3D ICs) implement heterogeneous systems in the same platform by stacking several planar chips vertically with through-silicon via (TSV) technology. 3D ICs have some advantages, including shorter interconnect lengths, higher integration density, and improved performance. Thermal-aware design would enhance the reliability and performance of the interconnects and devices. In this paper, we propose thermal-aware floorplanning with min-cut die partitioning for 3D ICs. The proposed min-cut die partition methodology minimizes the number of connections between partitions based on the min-cut theorem and minimizes the number of TSVs by considering a complementary set from the set of connections between two partitions when assigning the partitions to dies. Also, thermal-aware floorplanning methodology ensures a more even power distribution in the dies and reduces the peak temperature of the chip. The simulation results show that the proposed methodologies reduced the number of TSVs and the peak temperature effectively while also reducing the run-time.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.197-198
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• 2006

The high pressure compaction without internal lubricant and the high green density even with the pore free density were achieved by the newly developed die wall lubricant for warm compaction. This developed die wall lubricated warm compaction followed by high temperature sintering resulted in not only the superior mechanical property but also the low dimensional change. In this paper, the effects of increasing the green density on the sintered density, the dimensional change and the mechanical property are mainly discussed