It utilizes a closed impression die to obtain the desired shape of the component. The shaping is done by the repeated hammering given to the material in the die cavity. The equipment used for producing the blows are called drop hammers. In general drop forging will be done in two halves of the dies. The bottom half of the die is fixed to the anvil of the machine but the upper half of the is fixed to the anvil of the machine but the upper half of the is fixed on the heated stock is kept in the bottom die and the top die or ram delivers few numbers of blows on the metal. Die impressions are machined in the cavity, hence some complex shapes can be produced. But too much complex shapes cannot be produced like cavities, deep pockets etc due to the limitation of withdrawal of finished forging. The products produced are crankshaft, crank, connecting rod, crane hook, wrench etc.
The process of producing the shape of the component sis similar to that of the drop forging but in press forging the required amount of force can be obtained continuously in the squeezing action. This squeezing is obtained by means of a hydraulic press or mechanical press. Because of continuous force application, the material gets uniformly deformed throughout the its depth.
Differences between the Drop and Press Forging:
- The more hammer force is likely to be transferred to the machine frame in drop forging but in press forging the force is transmitted to the stock.
- The impression obtained in press forging is clean compared to the drop forging in which likely jarred impression is produced.
- Draft angle used in press forging is less than the drop forging.
- For the same amount of deformation to be produced, the force required in press forging is higher than the drop hammer forging.