In precision forging process, die technology is closely related to the performance, accuracy and processing mode of parts. The development of die technology is the key to promote the progress of precision forging technology of spiral bevel gears. At present, the research on precision forging die ofroughly includes the following directions: first, research on new die structure. By improving the forging process, on the basis of traditional open die forging, shunt die, closed die and floating die are developed, so as to reduce the deformation force and improve the manufacturing accuracy; The second is the optimization of die structure. Through process experiment and numerical simulation, the die wear is predicted and the structural parameters of the die cavity are optimized; The third is the research on die materials and die manufacturing technology. At present, high-quality mold materials and cavity fine machining technology are still under constant exploration.
In the research on the innovation of die structure, Kondo et al. Proposed the split forging method. Its principle is to set a split groove at a suitable position of the forging to make the metal flow freely during the filling process and reduce the flow resistance and forming load. Kouji et al. Developed a rotary die structure. When the tooth die returns, it is forced to rotate to demould the forging, which can avoid damaging the tooth surface during demoulding. In the research on the optimization of existing dies, Zhang Qingping and others separately used the modified modulus method and displacement method to design the tooth profile of cold precision forging die ofon the basis of shunt forging, and optimized it with the help of orthogonal test and numerical simulation to improve the filling performance of metal. Shu Qifu introduced the main process flow of precision forging process of spiral , and analyzed the selection scheme of electrode gear, preform shape and parting surface of tooth cavity. Tian Fuxiang et al. Summarized the characteristics of open die forging of spiral bevel gear, combined with the structure of spiral bevel gear, put forward a new process of small no flash precision forging.
In the research on die materials and manufacturing technology, song Juan analyzed the main failure forms and failure factors of spiral bevel gear cold extrusion die tooth profile, and put forward methods to ensure die life from die structure and heat treatment methods for various failure forms. Gao Zhenshan et al. Simulated the wear of spiral bevel gear hot forging die by elastic-plastic finite element method, calculated the wear amount at the easy wear position of the die, analyzed the influence law of different process factors on die life by orthogonal test, and determined the optimal process parameters for forging experiment.