Aluminium can shaping by hydroforming: simulative feasibility study and prototype production

In these last years, the demand of shaped aluminium bottles and cans was continuously growing. The main problem is related to the fact that normally these objects have very thin thickness and a high strain-hardened material due to the deforming production steps (deep drawing and ironing). In the present paper, a study about the residual formability of cylindrical can is reported. In particular, a first characterization of the flow stress of the ironed component and the identification of the maximum deformation reachable with the hydroforming process were carried out. On the base of these preliminary results, the feasibility of hydroforming aluminium can, namely a small bottle for soft drink, has been investigated. The process is similar to tube hydroforming, even if the bottom part of the can is closed and air is used instead of liquid. The main problems to be solved were related with the possible breakages of the cylindrical body during hydroforming. The process success depends on the material characteristics, the diameter and thickness of the preformed cylindrical body, the shape, the geometry and the dimensions of the final part and the media pressure. The research aims to study the process feasibility and to prove the ability of the simulation software in forecasting the material behaviour. All the simulation phases are supported by experimental tests aiming at validating the finite element method model and to realize sound prototypes of Al soft drink bottles. In such a way, it is possible to have a reliable tool to help the designer in optimizing the process and in identifying new feasible shapes.