STEP BENDING METHOD AND STEP BENDING APPARATUS WITH SINGLE ELONGATION VALUE SPECIFYING DEVICE

摘要

A bending apparatus for bending a workpiece W according to cooperation of a punch P and a die D previously carries out various step bending or makes simulation of step bending, and calculates an approximation formula based on a correlation between a ratio% of a one-sided elongation value alpha to a plate thickness t and a step bending angle &thetas; based on a relationship among the plate thickness t, the step bending angle &thetas; and the one-sided elongation value alpha of the workpiece W so as to store the formula as a database. The more accurate one-sided elongation value alpha of the step bending is calculated by small parameters including only two data including the plate thickness t and the step bending angle &thetas; previously input at the time of actual bending based on the approximation formula in the data base so that the bending is carried out easily. <IMAGE>