Modelling of cold extrusion with experimental verification

Abstract

This paper reports on an experimental and finite element analysis (FEA) of the cold extrusion of high-grade (AA1100) aluminium. The influence of die angle, reduction ratio and die land on the extrusion force during the extrusion process was investigated. A forward extrusion die was designed and manufactured for the purpose of the experimental research. Interchangeable elements of the extrusion die allowed rapid change of the extrusion parameters to attain a high degree of experimental flexibility. A load cell, incorporated into the die design, allowed accurate determination of extrusion forces while a linear variable differential transformer (LVDT) provided automatic measurement of punch travel during the extrusion cycle. All data obtained from the instrumentation was captured and analysed using a personal computer (PC). A finite element analysis (FEA) of the cold extrusion process was undertaken in parallel with the experimental programme. The FEA simulation was carried out using ELFEN, FEA software, specifically produced for metal forming simulation. An axisymmetrical 2D geometric model of the tooling and billet was constructed for the analysis. Data obtained from the FE model included die-work piece contact pressure, effective stress and strain and material deformation velocity. The correlation between the experimental, calculated and FEA data obtained in this research is presented and discussed.