Open-die forging

Forging is the process of shaping metal through the application of force. Open-die forging is also known smith forging. In open-die forging, a hammer strikes and deforms the workpiece, which is placed on a stationary anvil. Open-die forging gets its name from the fact that the dies (the surfaces that are in contact with the workpiece) do not enclose the workpiece, allowing it to flow except where contacted by the dies. Therefore the operator needs to orient and position the workpiece to get the desired shape. The dies are usually flat in shape, but some have a specially shaped surface for specialized operations. For example, a die may have a round, concave, or convex surface or be a tool to form holes or be a cut-off tool. It is different from closed die forging in that the workpiece is not enclosed by the dies and the dies themselves are more like tools with simple shapes and profiles rather than resembling enclosed molds.
 

Advantages of Open-Die Forging

Cogging is successive deformation of a bar along its length using an open-die drop forge. It is commonly used to work a piece of raw material to the proper thickness. Once the proper thickness is achieved the proper width is achieved via edging.Edging is the process of concentrating material using a concave shaped open die. The process is called edging because it is usually carried out on the ends of the workpiece. Fullering is a similar process that thins out sections of the forging using a convex shaped die. These processes prepare the workpieces for further forging processes.
 

Advanced open die forging techniques are capable of producing complex shapes even in large parts and products in addition to simpler shapes like bars, ingots, and rounds. While steel and related alloys are the most common subjects for open die forging, other metals can be shaped this way as well, including copper, nickel, and titanium alloys. The main drawback of open die forging is that the workpiece must be constantly moved as it is worked, requiring complex mechanical controls or skilled human operators, whereas closed die forging can be entirely automated and is a much simpler process.