| 摘要 |
PURPOSE:To obtain a method and apparatus for injection-molding plastic optical element, which can be produced by re-molding under the condition that the surface layer of a preform is efficiently heated just before re-molding by a method wherein the re-molding is performed under the condition that the surface layer of the preform in a mold is heated by being blasted with heated gas. CONSTITUTION:In an injection-molding equipment used for injection-molding the plastic optical element concerned, a preform 5 is inserted in a cavity 4, which is produced with an upper mold 2 and a lower mold 3. In the cavity 4, an air vent 6, which communicates with the outside of the molds, and a gate 7 are formed. Molding with the mold 1 having the above-mentioned constitution is performed by sending heated gas through a vent hole such as the gate 7 or the like communicating with the cavity 4 so as to be blasted against the preform 5 in the cavity 4 and, after that, discharged through the air vent 6. At this time, heat-exchanging is performed between the heated gas and surface layer of the preform 5, resulting in heating the surface layer of the preform 5. At this time, resin is injected for re-molding. Accordingly, the waviness of the surface of a molded article becomes small and efficient pre-heating can be performed. |
