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1 Journal of Achievements in Materials and Manufacturing Engineering

1 2008

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3D finite element analysis of metal flow in hot aluminium extrusion of T-shaped profile with various offset pockets

Carmai S. J. J., Pitakthapanaphong S., Sechjarern S.

Journal of Achievements in Materials and Manufacturing Engineering

2008

Vol. 31, nr 2

463-468

Purpose: The present paper has therefore investigated influence of offset pocket design on metal flow behaviour in hot aluminium extrusion of a T-shaped profile. Design/methodology/approach: A series of finite element simulations have been carried out by offsetting the centre of pocket cross-section and examining exit velocity distributions of the profile cross-section for each case. Findings: That the offset pocket has influence on the metal flow during extrusion process. Small distance between the edge of the pocket and the edge of the die leads to slow flow velocity but if the distance is large the metal can flow through easily, hence higher velocity. With the information from the analyses, the new pocket was proposed. The velocity difference across the cross-section of the extrude was smaller compared to the original pocket. The extrudate is straight and not bent. Offsetting pocket can therefore be used to control metal flow to the die. Practical implications: The appropriate design of pocket will help in regulating the metal flow and lead to a single bearing length or even zero length bearings. This is more favorable than a flat die with varying bearing lengths as a pocket die could be more easy to machine or correct especially extrusion of a thin walled profile. The pocket is usually required for extrusion of complex geometries. The fundamental understandings of pocket design are currently inadequate. It depends heavily on the experience of the die designer. Limited work has been done towards systematically examining influences of the pocket geometries and offsets on metal flow. Originality/value: The present paper has therefore investigated influence of offset pocket design on metal flow behaviour in hot aluminium extrusion of a T-shaped profile of which its cross-sectional width varies. Its shape factor is 6.76. The thermal effect has also been incorporate. An appropriate pocket die design for a T-shaped profile has later been proposed.