| 摘要 |
PURPOSE:To contrive to uniformize resistance to flows of filling resin in respective cavities at the final pressurizing and consequently facilitate the setting of the conditions at the final pressurizing and reduce the generation of voids by a method wherein the nearer the positions at which the cavity connects to a runner, are to a pot, the larger the opening areas of the vents of the respective cavities become. CONSTITUTION:Thermosetting resin 5, which is shaped in the form of a tablet, is charged in a pot 4 and melted by heating and pressurized with a plunger 3. The molten resin 5 is fed through runners 6 and respective gates 7 and filled in respective cavities so as to be molded in the form of lead frames. The nearer the opening sites of the vents 9 of the respective cavities 8 are to the pot 4, the larger the opening areas of the vents 9 of the respective cavities 8 are made. Concretely, since the area of the vent 9 of the cavity, the resistance of which to the flow of resin is larger during the proceeding of the setting of filling resin, is set larger, the sum of the resistance due to the setting resin and the resistance at the vent 9 becomes nearly the same at the respective cavities 8 and consequently the amount of resin discharged from the vent 9 becomes nearly the same at the respective vents, resulting in allowing to reduce defects due to the generation of voids. |
