Rotary Hammer Forging, a New Manufacturing Process

Rotary forging process has recently been developed in which the material is deformed partially and incrementally and a deformation zone is developed and swept through the material. Since the upper die in rotary forging is always in contact with the workpiece top surface, and presses continuously the workpiece until it takes the final shape in one stroke (i.e. resembling conventional press forging), it might be more definite to name it as rotary press forging. Rotary press forging produces many defects. The author has invented a process, namely, rotary hammer forging, which reduces these defects. The aims of the present work are to introduce the rotary hammer forging process, to study the effects of the fundamental process parameters, and to find out the advantages of Riff. Special set-ups with a rotary die mounted on a lathe chuck being hammered with a pneumatic piston mounted on the lathe carriage have been used. It has been found that the specimen's geometry and the inclination angle affect the extruded length, the mushrooming effect, the eccentricity, the twisting angle, the buckling and the forming time. The defects of buckling, mushrooming, eccentricity and twisting are less severe in rotary hammer forging than rotary press forging. Hence, rotary hammer forging is more beneficial and superior than rotary press forging.