Process design and control in cold rotary forging of non-rotary gear parts

This paper is aimed to investigate the process design and control method in cold rotary forging of parts with non-rotary upper and lower profiles. Using the analytical and FE simulation methods, three critical technological problems in the cold rotary forging process of this kind of parts are resolved reasonably. The first one is that an accurate design method of the non-rotary upper die is presented based on the geometrical and kinematic relationship between the upper die and upper profile of parts. The second one is that the interference judgment between the upper die and upper profile of parts can be achieved by analytically obtaining the trajectory of any point in the upper die. The third one is that the metal flow and geometrical accuracy of the non-rotary upper profile of parts can be effectively controlled through optimizing the process parameters. On the basis of the above research, the cold rotary forging process of a typical gear part, both the upper and lower profiles of which are non-rotary, is investigated numerically and experimentally. The results indicate that the desirable geometrical accuracy of the non-rotary upper profile of the gear part can be obtained, which verifies that the process design and control method presented in this paper is valid and cold rotary forging can thus be used to manufacture the parts with non-rotary upper and lower profiles. (C) 2014 Elsevier B.V. All rights reserved.