EXTRUSION TOOL, METHOD FOR MANUFACTURING SHAPED ARTICLE WITH FINS, AND HEAT SINK

An extrusion tool (10) according to the present invention includes a die main body (20) having a bearing hole (21) for defining an external configuration of the shaped article (1), the bearing hole (21) including a substrate forming portion (22) corresponding to the substrate (2) and fin forming portions (23) corresponding to the fins (3), and a plate member (30) to be disposed at an upstream side of the die main body (20). The plate member (30) is provided with a material passage (31) penetrating in the fore−and−aft direction and communicates with an upstream side opening of the bearing hole (21) of the die main body (20). The plate member (30) is provided with at least one vertical partitioning wall (33) (34) so as to cross the substrate forming portion (22) of the bearing hole (21) in the thickness direction of the substrate (2) in a state in which the plate member (30) is combined with the die main body (20), whereby the material passage (31) is divided into a plurality of small passages (31a)(31b)(31c)(31d)(31e& rpar;(31f). By using the extrusion tool for extruding a shaped article with fins such as a heat sink, excellent degree of flatness of the substrate can be obtained.