Influences of electric-hydraulic chattering on backward extrusion process of 6061 aluminum alloy

The possibility of the electric-hydraulic chattering technology and its application in the cold extrusion were presented. The conventional and electric-hydraulic chattering assisted backward extrusion processes were performed on 6061 aluminum alloy billets at room temperature. The experimental results showed that 5.65% reduction in the extrusion load was attained if the die and ejector were vibrated at a frequency of 100 Hz and amplitude of 0.013 mm in the longitudinal direction. The friction coefficient at the billet and tool system interface determined from the finite element analysis (FEA) decreased from 0.2 without chattering to 0.1 with application of electric-hydraulic chattering. The higher values of instantaneous velocity and direction change of material flow were achieved during the chattering assisted backward extrusion process. The strain distribution of the chattering assisted backward extrusion billet revealed lower maximum strain and smoother strain distribution in comparison with that produced by the conventional extrusion method.