| 摘要 |
PURPOSE:To prevent occurrence of laps at the end face of links and to improve the flatness of the end face, by regulating the width of the parallel section of the cutting edge of the trimming die which performs punch trimming at the end face of links to >=1/2 of the width of the end face of links. CONSTITUTION:A blank material 1 which has been subjected to the heating, rough forging, and finish forging is placed on a stripper 4 and a punch 5 is lowered. Then, the blank material is subjected to punch trimming work by a punching die 6 for trimming, whose parallel cutting edge part has a width which is >=1/2 of the width of the end face of the link. In this way, occurrence of fins at the end face of links is prevented and the flatness of the end face is improved. |
