Simulation of Warm Forming of 5754 Sheet Aluminium

In November 2009 a project was set up to implement an innovative metal forming process into the automotive industry with the goal of producing lightweight, high accuracy, complex-shaped automotive aluminium panels using one main forming operation. The project was known as WAFT - Warm Aluminium Forming Technology - and was part-funded by the UK Technology Strategy Board. The opening premise was that increased formability could be achieved with existing aluminium grades when heated to temperatures in the range 200°C to 350°C [1]. At these temperatures the material does not undergo re-crystallization or achieve superplasticity yet still exhibits increased formability - but the optimum settings for blank and tool temperatures, and also forming rate, were not known. The project aim was to industrialise the warm forming concept to align with conventional cold processing in order to develop a manufacturing process that could achieve steel formability with aluminium. This was to be confirmed in an industrial cell running a demonstrator tool, at rates optimised for premium vehicle production. The grade of aluminium chosen for the study was 5754; this is widely used for cold forming automotive body-in-white structural panels, and issues regarding assembly and behaviour in the vehicle are well understood. However, the reduced formability of 5754 compared with steel drives body-in-white design to adopt simpler forms and more numerous parts in sub-assemblies to create the required levels of complexity - all of which has significant cost implications and an impact on the overall carbon footprint of the manufacturing process.