Microthermoforming Integrated in the Injection Molding Process for Fabrication of Film-Based Microstructured Parts

Abstract

Abstract Thermoplastic micro parts are commonly manufactured by the large-scale production technology of micro injection molding, with small wall thicknesses limiting the feasible flow length. In contrast, microthermoforming is an inexpensive technology to manufacture thin-walled microstructured parts, but connecting three-dimensional solid bodies, e.g. functional structures, is impossible. The novel combination of processing techniques, i.e. microthermoforming integrated in the injection molding process with dynamic mold temperature control enables the use of non-adhesive polymer melt to form thermoplastic films via back molding and employ adhesive melt to connect further structures. Additional heating the film with the back molding component represents a particular benefit in terms of reaching the required film temperature and leads to low temperatures prevailing in the mold. Simulative tools facilitate the understanding of film temperatures after back molding and can be used in a further step for the adaption of homogenous temperature distributions across areally distributed microstructures. Generally speaking, the technology is expected to allow for multifunctional, thin-walled microstructured parts produced in short cycle times.