Off-centric extrusion of circular rods through streamlined dies, CAD/CAM applications, analysis and some experiments

N. R. Chitkara

Research output: Contribution to journalArticle

Abstract

The previously given analytical method, which was based on the upper-bound theory, was used to design the streamlined dies and to investigate the three dimensional off-centric extrusion of circular sections from initially circular billets through linearly converging (ruled-surface) and smooth curved (advanced-surface) dies. For a reasonably correct upper-bound to the load, a set of generalised kinematically admissible velocity fields were derived on the assumption of Bezier-type streamlines by incorporating a special velocity function that takes care of the non-uniform material flow. Based on the present method, for a given reduction in area, material property, friction condition and off-centric positioning of the exit cross-section, computations were carried out to predict the upper-bound to the extrusion pressures, the deforming grid patterns and curvature of the extruded product. Experiments were carried out for some off-centric circular sections with varying die lengths and reduction in areas. A sophisticated CAD/CAM package was used in conjunction with the CNC and EDM processes to manufacture the streamlined dies for the off-centric extrusion of circular rods. Both the solid and split-type specimens made of tellurium lead under both the lubricated and the dry conditions were used for experimental investigations in order to assess pressures, deformation modes and to visualise the deforming grid patterns. The theoretical predictions were observed to be in good agreement with the experimental.

Original languageEnglish (US)
Pages (from-to)295-320
Number of pages26
JournalInternational Journal of Mechanical Sciences
Volume42
Issue number2
DOIs
StatePublished - Jan 1 2000
Externally publishedYes

Fingerprint

computer aided manufacturing
Computer aided manufacturing
computer aided design
Extrusion
Computer aided design
rods
Experiments
grids
Tellurium
billets
tellurium
positioning
Materials properties
friction
velocity distribution
curvature
Friction
cross sections
products
predictions

ASJC Scopus subject areas

  • Civil and Structural Engineering
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Off-centric extrusion of circular rods through streamlined dies, CAD/CAM applications, analysis and some experiments. / Chitkara, N. R.

In: International Journal of Mechanical Sciences, Vol. 42, No. 2, 01.01.2000, p. 295-320.

Research output: Contribution to journalArticle

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