Open Die Forgings

In open-die forging, a hammer strikes and deforms the workpiece, which is placed on a stationary anvil.  Open-die forging gets it's name from the fact that the dies (the surfaces that are in contact with the piece) do not enclose the piece, allowing the material to flow except where it contacts the dies.  Therefore the operator needs to orient and position the piece to get the desired shape.  The dies are usually flat in shape, but some have a specially shaped surface for specialised operations.  For example, a die may have a round concave, or convex surface, to be a punch to form holes or be a cut-off tool.