Apparatus and method for guiding and forming an extruded plastic wire

摘要

The apparatus has an area whose cross-section(1) can be varied to suit the extruded material. A wound section of flat material(3) forms the adjustable area. Wound flat material(3) comprises a thin metal sheet or several layers of one or more different materials. When wound the material forms overlapped areas in which the layers lie closely on top of each other. An inner end(7) of the wound material has a continuously decreasing thickness and is angled to the contact surface of the outer area of the flat material where it forms a helical line around the extrusion axis. Tags(10) at one end of the wound flat material aid guidance of the extruded product. Elongated holes extend either radially or at variable angles to the extrusion axis around the wound material in the overlapping area and remain partly uncovered. A mechanism(2) for varying the cross-section comprises moving rods arranged around the wound material. Alternatively the wound material is fastened at an outer end onto an operating mechanism. Independent claims are included for: a) a method for guiding and forming a extrudate in which the die gap and/or diameter of an extruder head is varied using an area of variable cross-section(1); b) an extrusion plant with extruder, extrusion head and calibration unit in which variation of the melt flow gap in the extruder head can be synchronized with the area of variable cross-section using the plant control unit.