The Theoretical And Experimental Research On Drawing Technology Of Curved Die

The drawing is the key technology on cup-drawing process, it is essential during blank forming. How to reduce limit drawing coefficient, cut down procedures, raise efficiency and reduce costs become one of the main research problems for drawing process on the premise of ensuring the quality of products.In this paper a kind of new curved die profile has been created by plastic theory and mathematical method: on the whole drawing process, the top of the side wall keeps in touch tangentially with the curved die throughout, which can reduce the friction resistance that caused by the round corner of the die and bending resistance, the force of the die profile on the blank deformation zone is also beneficial to make it bring on tangential compression deformation, thus it can use the blank which has a smaller relative thickness to draw without wrinkling, and beats target with reducing limit drawing coefficient, reducing procedures and lowering costs.By analyzing the forming process of the drawing, based on the analysis of mechanics, this paper has put forward the wrinkling criterion of the blank, deduced the wrinkling limit formula of the curved die sequentially.It can forecast wrinkling, fracture and spring back, compute the dimension of blank, compute the deforming force, estimate the abrasion of die, and optimize the lubrication scheme by numerical simulation.It has been proved that this kind of new curved die can reach smaller limit drawing coefficient by drawing experiment, the smallest limit drawing coefficient gotten in drawing experiment is 0.382.By drawing experiment, this paper has investigated the effect laws of anisotropic hardening parameter R and work hardening exponent n on limit drawing coefficient. And also has analyzed the relationship between the anisotropy in the blank plane and the earring ratio.The deeply theoretical and experimental research on drawing technology of curved die in this paper enriches and develops the fundamental theories ofstamping technology. Compared with general die, to use curved die can reduce limit drawing coefficient, reduce procedures, raise efficiency and reduce costs. The effect laws of process parameters on limit drawing coefficient which has been deduced in this paper provide a reliable theoretical basis for choice and design of the process in practice.