박판 핀 전단 비틀림 감소를 위한 블랭크 가압력의 최적화

Abstract

Progressive dies are commonly used to produce narrow sheet-metal electronic parts. The shearing operation for narrow sheet-metal pins often invokes the twist of the pin. The twist of sheet-metal pin mainly occurs in the final shearing operation and decreases as the blank holding force is increased. In this study, an optimal layout of the springs in the progressive die is pursued to minimize the twist of the pin by maximizing the blank holding force of the final shearing operation. For a target function of optimization problem, the blank holding force is expressed in terms of the location and stiffness of the springs. The constraint conditions satisfying the pre-set blank holding force of previous operations are imposed. The design of experiments (DOE) is adopted for optimization process. The experiments of DOE are implemented by analyzing numerically progressive die structure. Meta-model is then created with experimental results, from which the optimal design of the springs is obtained by the quadratic response surface method (PQRSM). The layout of the springs optimally found in this research is compared with that of the existing die to see and verify the reduction of the shear twist of sheet-metal pin.