| 摘要 |
A cylindrical metallic tube or pipe can be perforated rapidly without deformation of circular holes. The apparatus is driven like a conventional press device (10) which comprises a detachable upper mold (20) and lower mold (30) having half circular grooves (21,31). The end parts of grooves have punch guide holes (22,32) to ascend and descend the punch (50), and the punching process can be achieved without insertion of supporting mold into the metallic tube.
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