Blank Shape Optimization in Deep Drawing with Combined Restraint

One of the methods for increasing the degree of deformation in the deep drawing of the cylindrical parts is the method with the combined restraint. In this process, due to the high degree of deformation, the earing is pronounced and affects the quality of the final part. The paper focuses in optimization the blank shape in this process applying a method which combines a mathematical relation with the results of the numerical simulation. The mathematical relation connects the radii of the initial blank at the different angles with the sizes of the part heights at different angles. The numerical simulation using FEM was used for the heights determination at the main anisotropy directions considering different initial blank dimensions. An experimental work was done for certify the numerical results. The results confirmed that the optimization of the blank shape in deep drawing with the combined restraint is a key for improving the deformation process, for reduction the earing and for minimizing the material consumption.

Blank Shape Optimization in Sheet Hydroforming Process

Blank shape is one of the most important parameters of sheet metal stamping. In fact it can directly affect the forming quality of parts and it has to be taken in account in sheet hydroforming design. Reasonable blank shape not only can reduce materials and production cost but, also, it can improve the strain distribution of the material and product quality in the hydroforming process. However, it is not easy to find an optimal blank shape because of complexity of deformation behavior and presence of many process parameters like die radius, punch radius, punch speed, blank holder force and friction. In fact, they affect the result of the process i.e. tearing, wrinkling, springback and surface conditions such as earing. Even a slight variation in one of these parameters can result in defects. This paper reports numerical and experimental correlation for axis symmetrical hydroformed component using initial blank with different shape and size. Experimental tests have been carried out through the hydroforming cell tooling, designed by the authors thanks to a research project, characterized by a variable upper blankholder load of eight different hydraulic actuators. Two different initial blank shapes, square and circular, of same material and thickness have been used.

Topology Optimization of Blank Geometry for the Sheet Forming Process

The newly developed element exchange method (EEM) for topology optimization is applied to the problem of blank shape optimization for the sheet-forming process. EEM uses a series of stochastic operations guided by the structural response of the model to switch solid and void elements in a given domain to minimize the objective function while maintaining the specified volume fraction. In application of EEM to blank optimization, a sheet forming simulation model is developed using Abaqus/Explicit. With the goal of minimizing the variability in wall thickness of the formed component, a subset of solid (i.e., high density) elements with the highest increase in thickness is exchanged with a consistent subset of void (i.e., low density) elements having the highest decrease in thickness so that the volume fraction remains constant. The EEM operations coupled with finite element simulations are repeated until the optimum blank geometry (i.e., boundary and initial thickness) is found. The developed numerical framework is applied to blank optimization of a benchmark problem. The results show that EEM is successful in generating the optimum blank geometry efficiently and accurately.

Research on Methods of Sheet Blank Shape Optimization for Drawing of Complex Special-Shaped Boxes

The reasonable blank shape is very important for drawing forming quality of sheet. In this paper, the blank shape is obtained by inverse calculation based on final drawing workpiece, with finite element software. The optimal blank contour is determined by modifying the 3D models of final drawing workpiece and comparing with forming quality of the different inverse calculated blank shapes, according to the stress and the material flow law in drawing process. The results show that, in the case of the given shapes of workpiece, the blank shapes with high precision can be obtained, the formability becomes better, and the number of drawing forming can be reduced by using the method. The method may also contribute to the drawing of large and medium-sized panels, rectangular boxes and special-shaped parts.

Blank Shape Optimization of Square Cup Deep-Drawing under the Unilateral Constrained Condition

To satisfy the forming need of single-basin with a flange, sensitivity analysis is used to optimize the shape on the basis of the initial shape which gotten by the backward simulation method of analysis software ETA/Dynaform5.5.The optimum blank shape for unilateral constrained square cup deep-drawing is determined, and the optimized results were analyzed and compared before and after. Some measures about blank optimization will be given to such parts.