Research On Forming Force Of Open Punch Rotary Backward Extrusion

With the progress of human society and the development of science and technology,people are increasingly aware of the importance of energy saving and high efficiency.Extrusion,as one of the main processing methods of industrial production today,its energy consumption occupies a large proportion.How to reduce the extrusion force has become a subject hot spot of scholars from various countries,and various new technologies have been proposed.Based on the existing research,North University of China proposed a process named open punch rotary backward extrusion.This paper analyzes and studies its forming force.By studying the speed change in the forming process,a kinematics permissible velocity field of the open punch rotary back extrusion is established,and the upper limit method is used to derive the calculation formula of the open punch rotary back extrusion force.According to the finite element theory,a numerical simulation model for the rotary back extrusion of the open punch is established.The Deform-3D software was used to simulate and study the variation of the forming force of the open punch under different friction coefficients,extrusion temperature,extrusion speed,rotation speed and punch slot angle.The results show that the extrusion force increases with the increase of the friction coefficient;within a certain temperature range,as the temperature of the extrusion increases,the extrusion force decreases;the greater the extrusion speed,the greater the extrusion force;As the rotational speed of the punch increases,the extrusion force gradually decreases;with the increase of the punch's slot angle,the extrusion force first increases and then decreases.The Gleeble-3500 thermal simulation testing machine was used to carry out an open punch rotary back extrusion experiment on the above parameters.The experimental results show that the rotary back extrusion process of the open punch can greatly reduce the extrusion force.The theoretical calculation results of the forming force are compared with the numerical simulation results and the experimental results.It is found that the upper limit solutions are both larger than the numerical simulation value and the measured value,and the error is less than 6%.The theoretical calculation results are consistent with the experimental data.It shows the accuracy of the calculation formula,and provides a theoretical basis for the further development of open punch rotary backward extrusion...