Numerical Simulation and Experiment Study on the Blanking Force for AISI-1020 and AISI-1045 Fine-blanking with Negative Clearance

摘要

Machining experiments of fine-blanking with negative clearance show that the blanking force is very different from ordinary blanking in different blanking stages. Studying on the blanking force size of fine-blanking with negative clearance in different blanking stages is a very important significance for studying die wear and analyzing the state of material stress-strain. Firstly, numerical simulation and stress state analysis of the fine-blanking with negative clearance are carried out, with DEFORM-metal forming finite element analysis software. Afterward the relationship curve of blanking force and stroke are measured, and the blanking force with different blanking stages of fine-blanking with negative clearance is analyzed by the simulation and the experiment. The analysis result shows that the simulation blanking force is bigger than the experimental result (error about 15%), but the blanking force variation tendency is accordant. while the punch pushes down within 0.1mm, the blanking force changes quickly. The metal sheet will enter into the state of plastic deformation after the blanking force reaching maximum value. Along with the punch continues to move down, the area of shear zone is decrescent so that the blanking force inches down, and the blanking force reaches a certain value in the place of blanking allowance value finally. With punch pushing the metal sheet to enter the plastic state and punch downward the place of the allowance value, the metal sheet sustained the big blanking force all the time as well as the deformation zone material keeps the plastic deformation. The research result provides theoretic reference and the experimental data for the practice application of fine-blanking with negative clearance, and has instructive significance and reference value to mould design.