Self-bending extrusion molding of distorted channels

Abstract

Using an integrated profile extrusion and bending forming process with a streamlined extrusion die, a new self-bending extrusion molding technology is proposed with an axis-distorted variable channel. By designing the streamlined extrusion die structure of the distorted central axis, the metal was made to flow non-uniformly in the die cavity, thereby directly extruding a bent profile. The central axis of the streamlined extrusion die is described by a trigonometric function and a Gaussian function. A numerical simulation was applied to analyze the metal flow pattern, equivalent strain, and strain-rate distribution during the self-bending extrusion process. The influences of the extrusion velocity and the addition of a bearing on the self-bending deformation profiles were investigated. During the extrusion process, the streamline at the center of the billet could describe the overall flow of the metal in the die cavity, and the distance between the point on the end face of the die outlet and the center of the die outlet directly determined the degree of extrusion and bending. The greater the distance was, the larger was the degree of bending. The metal strain on the convex edge of the die was greater than that on the concave edge of the die, with the extruded profile always bending toward the concave edge. The strain rate of the metal changed the fastest near the most convex point of the die. As the extrusion velocity increased or more bearings were added, the radius of curvature of the extruded profile increased nonlinearly.