A method of assembling a substrate with a part is provided. The method includes a step of structuring the substrate by a pulsed laser. In one example, the substrate is metallic and the part is polymer-based. The structuring step engraves grooves into the substrate in a pattern determined by the relative motion of the beam and the substrate. The pattern is configured to provide improved adhesion between the structured substrate and a part after assembling the substrate and the part by laser welding. The method of assembling may further include a pre-treatment step of the structured surface to allow improve laser absorption during the welding assembling.