| 摘要 |
<p>A method for manufacturing perforated plastic pipe, in particular corrugated thermoplastic pipe which are perforated by at least one punching member. A movement is imparted to the punch members in the direction of conveyance of the plastic pipe, which equals the rate of conveyance of the pipe. During the punching operation the punching member or members retain a substantially perpendicular position with respect to the plastic pipe.</p> |
