| 摘要 |
PROBLEM TO BE SOLVED: To provide a tool having such a shape as spiral shaped projecting and recessing inner diameter represented by the expensive tool so called a chamfering cutter, at a low cost. SOLUTION: This extrusion compacting method is the one, by which a mandrel 5 having the projecting form continued as the spiral shape on the outer periphery is disposed in the opening part of a die 2, a material to be compacted is extruded from a gap between the die and the mandrel, and this mandrel is rotated in the direction corresponding to this spiral. This extrusion compacting apparatus is the one which supplies the material to be compacted from the rear end side and is composed of a mouth-piece member having the die part and the mandrel at the front end side. The mandrel is composed of a shank part 4 extended to the front end side from the rear end side of the mouth-piece 1 and a compacting part 3 having projecting form continued as the spiral shape on the outer periphery positioned in the opening part of the die on the extending line at the front end side of the shank, and is rotated in the direction corresponding to the spiral.
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