Influence of Cold-Rolling on Incremental Sheet Forming of Polycarbonate

Since product customization is becoming more and more popular, high process flexibility is required in many industrial sectors. Incremental sheet forming shows versatility and its effectiveness can be improved when coupled with other processes to, for example, change the behavior of the material to be processed. This study combines two technologies, i.e. cold-rolling and incremental sheet forming, for the manufacture of thermoplastic components. Polycarbonate sheets were firstly cold-rolled to reach the desired thickness and then formed incrementally, to study how the first process (which modifies the mechanical behavior of the sheets) influences the second one, e.g. in terms of formability limits and forming forces. To this end, an experimental campaign, covering tensile tests and the manufacture of fixed and variable slope angle frusta by single-point incremental forming, was carried out on parent and cold-rolled sheets. The tests point out the correlation between the tensile behavior and some of the main features of the incremental sheet-forming process, like the maximum formability angle, the forming forces, failures and defects. In conclusion, the study provides a critical interpretation of the results to weight up the pros and cons of this integrated polymer sheet forming process