Hollow section form of the dies null hollow

摘要

PROBLEM TO BE SOLVED: To improve extrusion speed by using an extrusion die which is provided with a core having a hollow part and a thick-walled annular circumferential wall member whose inside is an extrusion material passage, and in which a side edge part is engaged with the annular circumferential wall member so that the core is directed in the extrusion direction. ;SOLUTION: A core 1 is preferably formed of a hard material such as cemented carbide and ceramics, and a hollow part forming part 1a is formed on its tip part. A female die 2 formed of the hard material and having a formed hole 2a which forms an outer circumferential part of a hollow member is stored in an annular circumferential wall member 3, and the core 1 is directly supported by the female die 2, or indirectly across a plate 4 to regulate the flow of an extrusion material. A core cover 13 is arranged at a rear part of the core 1, and preferably held by the annular circumferential member 3 close to the core 1 with an interval to the core. An extrusion material passage of the annular circumferential wall member 3 can be continuously and easily worked and manufactured through wire cutting.;COPYRIGHT: (C)1999,JPO