Closed die forging,also known as impression die forging,involves the pressing or hammering of preformed metal blanks into a set of dies shaped as a three dimensional negative of the part to be produced.In closed die forging process,the hammer and anvil fully enclose the workpiece,forcing the metal to fill all areas of the die.Closed die forging can produce a nearly limitless variety of 3-D shapes,and is capable of producing complex parts with tight tolerances.

Closed die forging is distinct from open die forging(refer to differences between closed die forging and open die forging),in which the die only comes into contact with part of the workpiece at a time. Initial costs for developing the processes and tooling for closed die forging can be quite high, but it is the most cost-effective forging method for high volume production, since recurring costs for each part are very low. In addition, closed die forging is capable of producing both symmetrical and non-symmetrical parts. Materials that frequently undergo closed die forging processes include high alloy steel, naval brass,carbon steel,aluminum,alloy metals,stainless steel,copper, nickel,tool steel and titanium.Application of closed die forgings are particularly often by industries such as electronics,aerospace, automotive,commercial,manufacturing,semiconductor,construction, hardware and food processing.