| 摘要 |
Extrusion mandrel assembly for continuous extrusion apparatus has a lobed, mushroom shaped, dolly formed with a central spacing stem located in the chamber adjacent a pair of discharge ports connecting respective exit apertures into an internal cavity in the chamber and a pair of shaped lobes having rear faces extending from central spacing stem, outer edge portions and front faces merging into a collar around a neck co-acting with an annular shoulder on extrusion die body to form an annular extrusion gap, with each lobe profiled so frictional surface drag on extruding material is uniform around lobed dolly. Individual paths between discharge ports and annular extrusion gap are equal in length as measured on respective surfaces of the rear faces, edge portions and front faces of profiled lobes. An extruded aluminium cylindrical tube up to 150 mm diameter and wall thickness of 1 mm to 4 mm may be formed avoiding discontinuities.
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