Mechanical Investigation of Recyclability for Sustainable Use of Laser-Based Metal-Polymer Joints

Metal-plastic hybrid components combine the strength of metal with the low density of plastic. Due to weight reduction, these components are becoming increasingly important. To reduce the need for raw materials, processes for the recyclability of hybrid compounds are being investigated to reuse the metal part. The aim of this research is to characterize the mechanical bond strength after laser-based cleaning and reuse of the metal component. For this purpose, laser radiation is used to introduce microstructures into the metal surface. Afterwards, the polymer is joined to the metal component with laser radiation. As a reference of the initial mechanical bond strength, the joined samples are examined in a tensile testing machine. The polymer residues remaining in the structured metal surface are removed with different laser-based cleaning strategies. The metal is used again to generate another hybrid joined sample with a new polymer component. The results of the subsequent tests in the tensile testing machine are used for a detailed analysis of the reusability. As a result of this investigation, the laser-cleaned specimens showed significant improvements in bond strength compared to the uncleaned specimens. The process of laser-based cleaning for the reuse of the metallic part of hybrid joined components provides a fundamental procedure for improving the circular economy. In the future, this study should be validated in subsequent investigations on realistic components with complex geometries.