Overmolding is a process where one material is molded over an already solidified part. To save labor costs, reduce cycle times, and achieve improved part quality two-shot injection molding is growing in popularity [1]. Adhesion between the overmolded materials is a critical requirement. In order to achieve adequate adhesion, the polymer chains in the overmolded surface must achieve sufficient mobility to allow interdiffusion or chemical reactions to occur. For high performance polyamides, this is often challenging due to their high melting points. For a symmetric flat interface, the contact temperature estimated as the average between the temperature of the first shot surface and the second shot melt temperature is well below the melting points of polyamides of interest. Trivially the contact temperature can be increased by either raising the mold and or melt temperatures. Practically, however, increasing the mold temperature leads to unacceptable cycle times or poor part integrity while concerns about degradation limit melt temperatures. Our idea to overcome the above problem which is explored in this work is to use InterFacial Geometries(IFGs). IFGs are protruding ribs with a favorable area-to-volume ratio which are able to accept heat from a larger volume of melt than a flat interface. By making first shot with IFGs, local melting can be promoted and adhesion achieved without detrimentally impacting cycle times or melt degradation. This study illustrates by a combination of modeling and experiment how IFGs work and can be optimized to give good adhesion in overmolding applications.