Abstract: A dobule-walled plastic box 20 is molded from a single parison 50 in an unlimited depth by closing the bottom of parison 50 and draping it downwardly over a core 60 so that a leading part of the parison forms an inside wall of the box and a following part of the parison forms an outside wall of the box. After parison 50 is draped over core 60, outer mold parts 61 close around the core and the draped parison; and the box is blown in a cavity between the core and the outer mold parts. The parison can be ballooned while draping down over the core to enlarge the parison to stand out from and surround the core, which can be raised during the draping process. Parison 50 can also be deballooned after draping to stay within the confines of outer mold parts 61 while core 60 raises and while the outer mold parts close.

Abstract: A double-walled plastic box (20) is molded from a single parison (50) in an unlimited depth by closing the bottom of parison (50) and draping it downwardly over a core (60) so that a leading part of the parison forms an inside wall of the box and a following part of the parison forms an outside wall of the box. After parison (50) is draped over core (60), outer mold parts (61) close around the core and the draped parison; and the box is blown in a cavity between the core and the outer mold parts. The parison can be ballooned while draping down over the core to enlarge the parison to stand out from and surround the core, which can be raised during the draping process. Parison (50) can also be deballooned after draping to stay within the confines of outer mold parts (61) while core (60) raises and while the outer mold parts close.

Abstract: A double-walled plastic box 20 is molded from a single parison 50 in an unlimited depth by closing and holding a bottom region of the parison at the bottom of a cavity 30, bringing together parts of a core 40 above the cavity to close off an upper region of the parison, moving the core, the cavity, or both vertically to position the core within the cavity and invert the parison so that a lower region of the parison forms an outside wall of the box against an inside surface of the cavity and an upper region of the parison forms an inside wall of the box against an outer surface of the core. The parison is then blown into a double-walled box 20 in the shape of an enclosed space between the cavity and the core.