The Butterfly Construction consists mainly of designing the mandrel section of a porthole aluminium extrusion die giving the bridges an arched shape. With this innovative architecture, the details in the undercut can be brought together by opening the external feeds and better supporting the difference in the flows called by the profile, thus achieving important results in terms of productivity and behavior of the porthole die during extrusion. A case study has been used to compare the behavior of a Butterfly Die™ with the one of a traditional Porthole die design. 3D FEM simulation will be used to develop the Butterfly Die™ in terms of feeding balance trough multiple ports.