摘要 |
A mold having a hole therein is provided, with a punch disposed within the hole in the mold surface. A portion of the punch extends out beyond the mold surface in an initial position such that the wall of the structure is initially formed therearound. The punch is movable to an activated position wherein the punch extends out beyond the mold to an extent greater than in the initial position. The punch is moved from the initial position to the activated position at a time interval after blow molding selected so that at least a portion of, and preferably a majority by volume of, the material forming the wall of the structure is in a molten state such that the cuffing edge of the punch forms a hole through the wall of the structure along a line substantially perpendicular to a direction of travel of the punch.
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