Application of the fuzzy-based Taguchi method for the structural design of drawing dies

In the sheet metal stamping process for automobiles, the drawing process requires the greatest stamping force, and thus the structure of the drawing dies is the thickest and heaviest among all stamping dies. This study describes how the fuzzy-based Taguchi method can be applied to explore multi-objective optimization in the structural design of drawing dies. Using the lower die of the drawing die for the engine hood??s outer panel as an example, the current study explores four parameters that primarily influence the strength and weight of their structure, namely the rib thickness of the punch open line, the pitch of the structure rib, the thickness of the punch surface, and the thickness of the structure rib. Firstly, CATIA software is used to construct a geometric model of the drawing die, and a structural analysis of the model is performed. Next, within the constraints of allowable stress, allowable deflection and allowable size and pitch of the rib, etc., we apply the Taguchi method to evaluate the allowable characteristics of the two objective functions, namely the deflection and weight of the lower die. Then, through factor effect analysis and analysis of variance, the influences of the design parameters upon the objective functions are determined. Next, a fuzzy logic inference is utilized to obtain the measuring index which results in the optimization of the multiple performance characteristics. Finally, by comparing the results from the maximized design and the results from the original design, it is shown that the deflection of the lower die structure is only increased by 0.0038?mm (8.1%), but its weight can be greatly decreased by 506?kg (12%).