Increasing demands on products and materials, as well as new applications, have led to innovative manufacturing strategies in recent years. Metal-polymer sandwich composites are usually produced conventionally by hot pressing. However, only simple geometries can be produced using this manufacturing process. To increase design freedom, current approaches aim to produce multilayer composites using additive manufacturing. By applying the components layer by layer, a more complex design of the sandwich structure can be realized. This method allows a differentiated design of both the outer cover layers and the inner core of the structure.

A major disadvantage of sandwich structures made from several materials is the complex recycling process. Direct pressing of polymer and sheet metal usually makes it difficult to separate the constituent parts. New research approaches use adhesive films that separate the metal and polymer cleanly and specifically at the end of the component's life via thermal activation.

In this case, the outer layer of the sandwich composite consists of a laser-roughened aluminum sheet, while the core layer of polycarbonate or polyamide is applied in an additive process. Instead of an adhesive film as a boundary layer, the thermoplastic adhesive was converted from granulate to filament and then also applied additively. By using a printer with several print heads, contamination of the individual layers could be avoided. The additively applied adhesive was compared to an adhesive film from the same manufacturer using shear edge tests.

The new possibilities this opens in terms of geometry and material distribution make it possible to create new optimized structures that improve the mechanical and thermal properties, which will be investigated further in the future.