Patent ID: 9555505
Date: 2017-01-31
CPC Classifications: B21C,B21K,B23P,F28F,H01L,Y10T

Claim:
1. A forging method for forming a heat sink including a base board and a plurality of pin fins integrally formed on at least one surface of the base board by plastically deforming a forging blank by die forging processing, the method comprising: arranging a back pressure applying pin in a fin-forming hole for forming the pin fin in a slidable manner, the fin-forming hole being formed in a forging die, wherein the back pressure applying in includes a concave portion on a restraining tip end face of the back pressure applying pin; applying a back pressure to a metal material of the forging blank flowing into the fin-forming hole with the back pressure applying pin at a time of plastically deforming the forging blank; restraining the metal material with the concave portion on the restraining tip end face of the back pressure applying pin; and integrally forming a joining convex portion on a tip end of the pin fin by the metal material filled in the concave portion.