Prediction of curvatures of parts extruded through rotary die using fuzzy inference

A fuzzy model for predicting the shapes of rectangular bars with variable curvatures along their lengths in the extrusion system with rotary dies, whose mechanism has been developed by the authors, is proposed. In the fuzzy model, the height of the die aperture, the inclination angle of the die, the angular velocity of the rotary die and the distance between the predicted and the experimental central lines of the extruded bars, namely the error of the prediction, are used as the antecedent parameters, and furthermore a linear relation is assumed among the parameters and the curvature of the extruded bar. The shapes of the bars predicted by the proposed fuzzy model are compared with those obtained in the extrusion tests in order to evaluate the accuracy of the prediction. The distance between the predicted and the experimental central lines is confirmed to be less than 4.0% of the height of the extruded bar for all of the experimental conditions.