Making tubular lines using the gas internal pressure molding process, fills two regions in molding cavity, injects second transparent plastic and finally, gas

摘要

Initial injection fills two regions in the mold cavity (3, 5), leaving an empty zone (6) between them. A second transparent plastic is then injected by the nozzle (2). This plastic runs along the cavity, (limb 4 is now blocked), displacing still-fluid first melt from the interior and spreading it along the empty zones (6). A third stage of fluid (gas) injection completes the line.