抄録
In offset bending techniques, it is difficult to obtain identically shaped parts in the same operations because slight variations in mechanical properties and thickness of materials and forming accuracy in bending operations affect the configurations of bent parts. This paper deals with discrepancies in angles between loaded and unloaded states of main bent portions in order to furnish data for approved models of bending dies. These angles are measured using photographic techniques, and the springback and the difference in angles of parallel portions are calculated from these angles. The magnitude of these discrepancies depends on the bending angle and the bending height of the die setup and the sheet thickness, and relates to the loose fitness of bending sheets in dies at the final stages These discrepancies in die configurations and sheet thickness are well correlated with the ratios of the slope length to the arc length of dies.
