Flexible tooling system using reconfigurable multi-point thermoforming technology for manufacturing freeform panels

In this paper, authors present a highly flexible tooling system based on reconfigurable multi-point thermoforming (MPTF) methodology, which has been developed within an EU-granted FP7 project. The MPTF technology employs an actuated-punch matrix to dynamically configure a controllable tool working surface through digitally adjusting relative displacement of each punch in the matrix. Novel MPTF methods have been proposed through re-changing configurations of actuated-punch tooling system according to rapid thermoforming principles and relevant cladding applications. The tooling system includes an industrial-scale prototype of an MPTF tooling integrated with functional CAD/CAE/CAT software interfaces. The numerical simulation with an explicit FEM predicts the unexpected deformation defects of dimples and wrinkles regarding to discrete contact boundaries between punches and the sheet blank. Innovative techniques of variable blank-holder and deformable cushion have been implemented to suppress wrinkling and eliminate dimpling effectively. The tooling system has been successfully applied to manufacture complex double-curved panels, which are described as application examples. Compared with conventional fixed moulds, the flexible tooling offers robust, rapid and re-changeable means to make mould-less manufacturing large freeform panels.