Production of polymer-metal hybrids using extrusion-based additive manufacturing and electrochemically treated aluminum

•Electrochemical microstructuring enables the production of polymer-metal hybrids by means of Material Extrusion without the need of coatings.•The contact temperature between the metal sheet and the deposited polymer significantly influences the resulting component behavior.•A consolidation roll improves the filling of microstructures for low contact temperatures. The development towards higher individualization and functional density pushes the need towards a flexible production of multi-material and lightweight components. In this paper, extrusion based additive manufacturing was used to produce polymer-metal hybrids with polypropylene and aluminum alloy. For this purpose, a screw-driven extruder on a six-axis robot was used. Due to the adhesion incompatibility of polypropylene and untreated metals, the surface of the aluminum sheets was electrochemically micro-structured. The investigations show that this enables a mechanically stressable joint through the filling of the surface microstructures with polymer. Investigations on lap shear joints reveal a distinct influence of the contact temperature between the polymer and metal onto the lap shear strength. A sufficient contact temperature is required for filling surface microstructures. Thus, increased metal and extrusion temperatures favor higher strengths. Furthermore, the use of a consolidation roll shows beneficial influences in lower temperature ranges due to the application of higher pressures during the polymer strand deposition.