The invention relates to a method for manufacturing a sandwich panel as a semi-finished product where at least one layer (2, 12) of a non-metallic material is positioned between at least two metallic layers (1, 3; 11, 13). At least one of the metal layers (1, 3; 11, 13) is shaped into a three dimensional layer (3, 13), and the metal layers (1, 3; 11, 13) are achieved to be in directly mechanical contact to enable resistance weldability of the semi-finished product in order to connect the semi-finished product to a desired combination of solutions in a subsequent manufacturing process.