Design And Application Of The Slope Structure For Drawing Die

Along with the computer numerical simulation technology and the finite element plasticity forming theory unceasing development, the numerical simulation can achieve the quite high precision, it already has become the most effective research technique to the metal plasticity formation at present. Carries on the numerical simulation to the sheet forming process, the stress and strain which happened in deformation process can be understood comprehensively, and the formation flaw can be forecasted, base on this , the design parameters can be adjusted facilitately and the satisfaction formation workpiece can be obtained, finally the reasonable part can be designed and manufactured according to the numeral simulation results ,through these methods, the design and the production cost can be reduced effectively, the new product research and enterprise's market competition ability was increased enormously.In the sheet forming, the wrinkle, the crack and the springback are three kind of main quality flaws, in which the crack are the most common flaws. The crack usually appears in the material minimum thinness spots, mainly caused by the following factors: the material withstanding radial direction tensile stress oversized which caused the material to enter the die difficultly , or the punch and die,s fillet is too small, the drawing depth oversized and so on. At present the crack can be solved mainly by adjusting the press force, the stretch gap, the die and punch radius, the materials size and so on. Although the above each kind of present solution in the actual production usually need spending lots of labor forces and the cost is too high.In this paper, the characteristic of the material fluxion and the stress and strain which happened in the forming process was analyzed, the crack flaw,s formation reason and the solution was discussed. Taking the development of drawing die for the front side panel as an example , by using software DYNAFORM,the whole process of sheet metal forming for the front side panel under given forming conditions is simulated,the crack can not be removed by means of adjusting the holder force and radius etc. , so in this paper a kind of slope structure which can improve the material fluxion circumstance and decrease the thinning is introduced firstly,the mechanism of the slope structure is studied from the mechanics,base on the above research ,finally the crack phenomenon was removed successfully by using the slope structure,accordingly the economical and reasonable die construction is designed and the qualified product is produced successfully.A lot of Square box simulation drawing experiments was carried on by using FEM software eta/Dynaform, the simulation results was obtained and the results was discussed. Then the orthogonal experiment was designed, through the test results we can find that the thinning influence decrease is in turn the slope angleθ, the punch fillet R, the slope heighth and the die fillet r .Based on this ,we choose five primary factors such as the slope angleθ, the punch fillet R, the slope height h, the die fillet r, the thinness to discuss these factors how to influence the thinning separately, then the rule of thinning,s change along with the main factors was obtained.Finally, taking the development of drawing die for the front side panel as an example , by using software DYNAFORM, the slope structure was used to optimize the drawing die face, the crack flaw was solved successfully, the reasonable die was designed, a new method to solve the crack and the similar question was provided.