Design of the semi-closed die for shaping the thick coin-like carbon steel parts in a single operation

Abstract

The current study strives to improve the precision and accuracy of a die and reduce unnecessary production steps. Upset cold forging for thick coin-like carbon steel parts were studied and redesigned for a single operation. The slug used in this experiment was an annealed AISI 1020 carbon steel bar sheared into cylinders having a height to diameter ratio (h0/d0) of 2.07. The design problem is to prevent an inclined slug surface due to surface roughness when it is loaded in the die cavity. The redesigned die is semi-closed with a fixed support at a position 0.25 of the initial height of the slug. Six springs were employed to set the start-to-finish position during forging. The results showed that slugs with rough and uneven surfaces, with an h0/d0 ratio of 2.07, could successfully undergo a single forging. Furthermore, the upset forged coin was designed to have a straight 2.4 mm outer edge, providing area for a set of mechanical fingers to grasp the workpiece during transfer to subsequent steps in the work process of a vertical and/or horizontal forging die set.