Punch Deisign And Punching Process Study For Complex Cross Section High Strength Parts

High-strength cross-section parts,such as bumper and rocker are usually punched to achieve mass production after forming process.Due to high strength and unreasonable punch mold design,mold wearing and chipping,poor section quality and low service life of mold are the main challenges.Therefore,designing a reasonable punch mold profile,selecting suitable punching parameters,are of great significance to improve the part performance and reduce the frequency of mold repairing,thus improving the production efficiency and saving manufacturing costs.In this paper,the research on the punching of complex cross highstrength steel parts is carried out from the aspect of the part punching process and the design method of the punch mold.The influence of different parameters on the section geometrical appearance and blanking force is studied.An accurate simulation model on the punching process of the complex cross section high-strength parts is established.Then the punch mold design method is studied based on the model.Finally,the design principle of the punching mold on complex cross-section parts is summarized.Main contents of this paper are given as follows:1)A straight edge shearing and punching experimental platform for high-strength steel is established.Based on the straight-edge shearing experiment,the influence of the process parameters and the material parameters on the geometry of the part is studied.Based on the punching experiment for different high-strength steel materials,the influence of the gap on the blanking force is studied.Finally,the optimal parameters are obtained by combining the straight-edge shear and punching experiment.2)Based on the optimal parameters obtained,a simulation model on the rocker punching process is established using the ABAQUS / Explicit software.A set of experimental method for identification and calibration of material parameters in fracture model is studied to obtain the fracture mode of the material.3)The cause of punch mold wearing and chipping is studied based on some simulation results.The design method of punch mold is discussed from the point of view of optimizing mold loading.By designing the punching angle and punching sequence,an optimal design method of the mold is obtained,the mass production tracking experiments show that the design method can greatly reduce the frequency of punch mold repairing.Then the punch mold design principles on similar cross-section parts are summarized,which can provide guidance for punch design.