Aluminum sheet surface roughness correlation with adhesion in polymer metal hybrid overmolding

In recent years the direct-adhesion polymer metal hybrid (PMH) technology has been increasingly used in replacing all-steel load-bearing structural components especially in automotive front-end modules. This work investigates correlations between the surface topography of aluminum sheet, injection overmolding process parameters and adhesion between polymer and metal. To this end several mold surfaces were prepared by shot peening aluminum sheets. Adhesion was measured using the shear test. Different microscopy techniques were implemented: optical microscopy for statistical characterization of adhesion at different process conditions, scanning electron and scanning probe for characterization of the adhesion phenomenon at the micro- and nano-scale.