Extrusion method and extrusion apparatus

Abstract

The invention relates to a method and an apparatus for extruding sections from materials, such as aluminium or aluminium alloys, in which material which has been rendered plastic is forced through an extrusion gap formed in a die and in which the extrusion gap is bounded by separate, mutually oppositely situated running surfaces, in which method, as a consequence of the shape and/or length of the running surfaces and/or width of the extrusion gap, the material forced through the extrusion gap experiences a lower resistance at one side of the die than at the other side of the die, more material being forced through the extrusion gap at said one side than at said other side, a curved section being formed as a result of the difference in the amount of material at the one side and at the other side, the longitudinal axis of said section having a curvature with a certain radius. The longitudinally curved section emerging from the die is passed through a curved guide device after leaving the die, the curvature of the guide device essentially matching the curvature of the curved section. After emerging from the die, the section is cooled, after which it is clamped by gripping means and is pulled by the latter in such a way that the rate at which the section is extruded is kept essentially constant.

Dependencies are inferred from the claim text.