Analysis of Open die Forging

Abstract

Open die forging is a long established process which can be used to produce a wide range of shapes. Its characteristic features in relationship to closed die forging processes are that it requires low forming loads, and with a small range of simple tools a wide variety of shapes can be produced. Deforming the workpiece is essentially incremental and manual skill and experience in manipulating the workpiece between the tools plays an important part in producing the required profiled product. This however has resulted in a diminished utilisition of the process. In this paper a general computerised methodology is proposed for small batch manufacture using a programmable press in conjunction with a workpiece manipulator. Elementary analysis, based on the upper bound method, with a simple kinematically admissible velocity field is introduced for restricted block forming, thus enabling the load and metal flow to be predicted for open die forging of rectangular sections locally deformed between two flat dies.