Numerical Simulation And Parameter Optimization In The Process Of Closed Extruding-type Fine-blanking

Fine blanking is an advanced technology that is used to manufacture platelike sophisticated contour parts, but demand high plastic and finite thickness. Closed extruding-type fine-blanking in this thesis is a new-type fine-blanking technology that can be applied to fine-blank the thick plate materials with low plastic feature. For the time being, this technology has got the patent right for invention and has been done some preliminary research; however, the fundamental study in this new technology when applied in engineering practice is not enough, especially the involved process parameter optimization has not been solved. This thesis plans to study the technological rule of closed extruded-type fine blanking through numerical simulation and physical experiments and optimize related process parameters to enrich its technology system, setting the stage for industrial application of this new technology.This paper made a tensile test on materials firstly, evaluate the flow stress equation of material based on obtaining the material performance parameters, and then calculate the computational formula on blank's volume through volume equal theory, building finite element simulation model. Then the author made the finite element simulation on closed extruding-type fine-blanking with the volume forming simulation software--Deform 2D. Secondly, it analyzed the regular pattern of fracture and damage influenced by the stress state of material in deforming zone based on referring previous study and experiments. Then, the author studied the influence law and degree of smooth zone proportion in shear plane affected by counter force and each process parameters of material (clearance between punch and matrix, fillet radius of matrix, inclination angle of cavity cone of matrix, pressure feeding length of matrix, and the preset altitude difference between punch and vice matrx) and the relations between the inclination angle of matrix and mould clamping force. Finally, the author designed and manufactured related experimental mould based on the finite element simulation, made related physical experiments, verified and revised the computational formula about blank's volume by changing the volume of different blanks; put forward the computational formula about blanking force, mould clamping force and the best counter force applied to closed extruding-type fine-blanking; studied the regular pattern of shear plane quality of workpiece counter force influenced by counter force and relative blanking clearance.The research shows that the fine-blanking force, mould clamping force and counter force of closed extruding-type fine-blanking obtained by finite element simulation is closer to the actual value, and the relative blanking clearance and counter force is essential and important for the shear plane quality of workpiece.