• Journal of the Korean Society for Precision Engineering
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• v.16 no.11
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• pp.116-121
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• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.232-235
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• 1995

A side-extrusion model, meant for deeper understanding of the material flow in the CONFORM (continuous extrusion forming) of trub shaped aluminum profiles is presented. In order to get the desirded straight shape of the extrudate,every part of its cross-section must exit the die with the same velocity. Problem is assumed by plane strain UBET-model to analyze it in a simplified way. This has been done by studying the side-extrusion through a two -hole die face. The flow is balanced by determining the optimum lengths of the bearing lands, i.e., those lengths which result in equal exit velocities of the extrudates. Furthermore, the material flow, as influenced by the punch velocity, has been investigated.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.05a
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• pp.66-74
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• 1999

일반적으로 압출용 빌렛트제조에는 빌렛트상하의 품질변화로 수평연속주조법이 사용되지 않고 있지만 전자기교반법을 이용할 경우 이러한 단점이 없어진다. 따라서 전자기교반장치를 설치한 수평연속주조장치를 이용하여 연주빌렛트를 제조하였다. 최대자속밀도가 1000Gauss 인 전자기교반장치를 설계 제작하였으며, 간접냉각방식의 흑연몰드에서 알루미늄합금을 사용하여 건전한 연주빌렛트를 제조할 수 있는 여러 공정조건을 조사 검토하여 직경 70mm의 기포가 없고 표면이 미려한 등축정을 가진 연주빌렛트를 제조하였다. 인출속도에 따른 수평 연속주조 빌렛트의 표면, 용탕유동라인 및 조직을 검토한 결과 평균인출속도 20mm/min에서 40mm/min까지 아주 미려한 표면특성을 가졌으며, 인출속도가 빠르면 유동라인이 표면에서 중심 쪽으로 완만한 기울기를 가지게 되어 표면응고층이 얇아져 빌렛트가 고액계면에서 끊어지게 되며, 조직미세화는 인출속도가 클수록 미세화되었으나, 결정구상화정도는 인출속도가 빠를수록 악화되었다.

• Korean Journal of Materials Research
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• v.8 no.7
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• pp.641-647
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• 1998

The machinability properties of P/M 2011 AI alloys extruded rapidly solidified by rotating disc atomization were investigated in this study. The Pb-Bi particles were very uniformly and finely dispersed in the P/M 2011 AI alloys extruded rapidly solidified. According to the increase of cutting speed, the short discontinuous chips were produceed and continuous chips were formed from the lower feed values of O.lmm/rev. The surface roughness is depend on the feed values, not cutting depth and cutting speed. The short discontinuous chips were formed due to dispersed $AI_20_3$ particles and Pb- Bi inclusion.

• Journal of Adhesion and Interface
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• v.2 no.4
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• pp.24-31
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• 2001

Polypropylenes(PP) with different melt index values were mixed with ethylene-propylene rubber(EPR) or ethylene-propylene diene monomer rubber(EPDM) and an ethylene copolymer containing carboxylic acid group in a twin screw extruder. Then test specimens were prepared from the pellets of the blends with an injection molding machine. The mechanical properties and morphology of fractured surfaces were measured. Relative peak intensities of carboxylic acid group on the specimen surface were measured with an attennuated total reflection infrared spectrometer (ATR-IR) and compared with each other. The blend specimens were found to have the gradient morphology of rubber domains in PP matrix in the core region and PP skin layer. The blends containing PP of higher melt index showed greater content of ethylene copolymer containing carboxylic acid on the surface when the relative peak intensities of ATR-IR for carboxylic acid were compared. As the melt index values were increased, the decrease tendency in mechanical propeties such as tensile strength and impact strength was more significant for PP/EPR blends than PP/EPDM blends.