Extrusion system with balanced flow passage

Abstract

A crosshead die for an extrusion system provides a balanced, even flow of molten material around a circumference. The die has a cylindrical body with opposite first and second ends, an outer wall, a horizontal centerline and a vertical centerline. The die further includes a reduced diameter end portion at the second end thereof. The reduced diameter end portion includes an axial bore. The cylindrical body further has a recessed surface in the first end, and a circular groove in the recessed surface. The groove has an inner edge and an outer edge and the outer edge includes two inwardly curved blending wedges which are positioned in opposed relation on the vertical centerline. The inner edge of the groove merges into a frusto-conical inner wall which tapers axially inwardly and merges with the axial bore in the reduced diameter end portion. The inner edge of the groove has a lesser height than the recessed surface. The cylindrical body further includes a flow inlet on the outer wall which is aligned with the vertical centerline. The body further includes first and second symmetrical flow channels which extend into the body from the flow inlet. The flow channels angle outwardly from the vertical centerline toward the outer wall and then turn forwardly to open outwardly into the groove.