The effect of process temperature on the formability of polypropylene based fibre-metal laminates

In developing a methodology for a robust stamp-forming process for glass-fibre reinforced thermoplastic Fibre-Metal Laminate (FML) systems, an understanding of the effects of process variables on critical formability measures is required. This study recognises temperature as the primary process condition and investigates the thermal profile of an FML for a range of potential processes. These profiles have been applied to the stamping of a channel section and their success quantified using shape error, bend radius and delamination measures. It was found that it is necessary to pre-heat the laminate to 160 °C followed by rapid transfer to the press tooling which should be heated to 80 °C. Once formed, the part should be held between the die and punch until the polymer has solidified. Significant improvements in shape error were achieved compared to monolithic aluminium formed with the same process. This indicates that in addition to providing significant weight savings, FML systems have potential for superior formability characteristics compared to monolithic aluminium material systems for large volume production of components using stamp forming.