[Show abstract][Hide abstract] ABSTRACT: 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.
Preview · Article · Jun 2007 · Journal of Materials Processing Technology
[Show abstract][Hide abstract] ABSTRACT: The extrusion process through a die aperture inclined at a fixed angle, previously proposed by the authors, is applied to forming of rectangular bars and tubes with various cross-sectional shapes, and the fundamental properties of the process are investigated. The curvature of the extruded bar is found to decrease as the height and width of the die aperture increase. The curvatures of the extruded tubes agree fairly well with those of the solid bars, and further, close correlations are found between the curvatures of the rectangular and H-type bars, and between those of the rectangular and H-type tubes. The curvatures of the rectangular bars and tubes with flanges can be predicted by combining the fundamental bending properties of the process obtained in extrusion of the rectangular bars with the shape effect of the bars and tubes.
No preview · Article · Dec 2003 · International Journal of Machine Tools and Manufacture