| 摘要 |
PURPOSE:To facilitate the deburring operation, preventing the corner bulging of a molded item and at the same time make it possible to clearly finish holes by a method wherein a parison is arranged between split molds, one of which has projected parts and the other of which has recesses, so as to blow-mold the parson after the projected parts fit into the recesses during the process of mold closing. CONSTITUTION:Plasticized plastic which is extruded from an extrusion head 17 in the form of a parison 10 is arranged between a mold 11, on the cavity 13 of which projected parts 15 are provided, and a mold 12, on the cavity 14 of which recesses 16 are provided. After that, with the proceeding of the closing of the split molds 11 and 12, the parison 10 is pinchingly pressed between the end face of the outer periphery 15a of each projected part 15 and the opening edge 16a of each recess 16 and then the projected part 15 is fitted beyond the opening edge 16a into the recess 16 so as to push the burr part F of each hole of the parison 10 surrounded by the projected part 15 and the recess 16 out of the cavity 14 and at the same time to thin the basic end F1 of the burr part F of the hole by the shearing force developed by the outer periphery 15a of the projected part 15 and the opening edge 16a of the recess 16. After that, pressure fluid is introduced into the parison 10 to blow-mold the parison 10 surrounded by the cavities 13 and 14. |
