Ironing of thin walled cans

Abstract

The ironing of thin walled cans has been analysed using the slab method and FEM. The results show that there exists a critical reduction ratio at which the ironing process may become unstable (or not self-centring). The results obtained show that the critical reduction ratio is heavily influenced by the geometry of the ironing die (semi-die angle and length of the die land), the friction conditions and the strain hardening of the material. An increase in the semi-die angle and/or length of the die land decreases the critical reduction ratio. If the friction coefficient in the punch-can interface is increased compared to the friction coefficient in the die-can interface, the critical reduction ratio increases. The critical reduction ratio also increases if the strain hardening of the can material is increased.