Development of a new method to determine bending sequence in progressive dies

In progressive dies, two or more stations are used to produce sheet metal components. In each station, one or more processes are applied. The progressive dies reduce the time and cost of producing complex sheet metal components. However, the design and manufacture of these dies are difficult. CAD/CAM systems have been proved to be very useful tools for this task. The main problem of CAD/CAM systems used in progressive die design is determining the bending operations sequence. In this paper, a new method for determining the sequence of the bending operations is described. In this method, sequencing is done in two stages. First, the bending operations, which can be carried out simultaneously, are defined by a classification method. In this method, all the bends are initially divided according to their bending directions (feed direction or perpendicular to it). Then for each direction, the bends are divided into operation groups according to classification rules. Three rules are used to determine the bending operation groups in this paper. These rules are based on relations between the bends in the component. The sequence of the bending operation groups is then determined using fuzzy set theory. Four components taken from industry and previous papers are used to show the capabilities of the proposed method.