Evaluation of the forming limit of aluminum square cups

摘要

Combined effects of process variables (blank shapes, tool shapes, blank materials and punchlubrication) on the deep-drawability of square cups were studied. Characteristic force lines toestimate the deep-drawability were introduced. The combined effects of the process variables wereexplained based on the force lines, the types of fractured cups and the thickness strain distribution.Moreover, the limiting drawing ratio could be easily evaluated from the force lines. The constantfracture force and the transitional fracture force were defined. These forces were used as the targetvalues for the improvement in the deep-drawability. The extent of the improvement in the deep-drawability was evaluated using the fracture forces.