| 摘要 |
PROBLEM TO BE SOLVED: To provide the highly efficient manufacturing method of a tube having high dimensional accuracy with different wall thickness or diameter for efficiently manufacturing the tube having differences in one or two or more of the wall thickness, the outside diameter and the inside diameter in the axial direction of the tube. SOLUTION: A plug 1 having a plurality of sections of different diameters is inserted into a tube 10, and while pressing the tube into a die 2 so as to be blanked, by moving the plug during the blanking, the plug diameter of a working portion is changed. By continuously pressing the tube into the die, supporting the plug on the inlet side or the outlet side of the die and moving the plug, and moving the plug to switch the plug diameter of the working portion from the small diameter to the large diameter, the inside diameter or the wall thickness of the tube is changed. Alternatively, by changing the outside diameter or the wall thickness of the tube by changing the plug diameter at the working section from the large diameter to the small diameter, and repeatedly performing switching of the plug diameter a plurality of times, the tube different in the inside diameter or the outside diameter at a plurality of portions in the axial direction of the tube is preferably manufactured. COPYRIGHT: (C)2006,JPO&NCIPI
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