Towa Corporation

Koichi Araki

Yoshihisa Kawamoto

Makoto Matsuo

Michio Osada

Takaki Kuno

Satoshi Nihei

In an apparatus for molding resin to seal electronic parts, an internal die space defined at least by pots, cull portions, resin passages and cavities when an upper mold section and a lower mold section are closed, is cut off or sealed from the exterior atmosphere. Thereupon the die space is evacuated using a first evacuation by a vacuum source and a second or instantaneous evacuation by an instantaneous evacuation mechanism. The vacuum source for the first evacuation may be an active vacuum pump, while the instantaneous evacuation mechanism may be a vacuum tank that has been previously pumped down, for example. Using this apparatus, it is possible to quickly improve the degree of vacuum in the internal die space by efficiently and reliably discharging air, moisture and gas from the internal die space to the exterior due to a synergistic action of the evacuation and the instantaneous evacuation. Consequently, the formation of voids in resin molded members is prevented.

Method of and apparatus for molding resin to seal electronic parts

In a method of sealing electronic parts with molded resin, a hollow sealing member is arranged on a mold surface of an upper mold section of a mold comprising the upper mold section and a lower mold section, so that the hollow sealing member is pressurized and expanded to convexly project from the mold surface of the upper mold section. In this state, the lower mold section is upwardly moved to be brought into contact with the expanded hollow sealing member. Further, an internal space portion, including pots, cull portions, resin passages and cavities, which is enclosed with the expanded hollow sealing member is set in a state isolated from the exterior when the upper mold section and the lower mold section are closed, so that the internal space portion is forcibly evacuated in this state. Thus, air, moisture and gases are efficiently and reliably suction-discharged from the internal space portion, whereby the internal space portion is set at a prescribed degree of vacuum. Consequently, it is possible to avoid contamination of air, moisture and the like in melted resin materials, as well as to prevent formation of voids in resin-sealed compacts.

Method of sealing electronic parts with molded resin and mold employed

In a method of molding resin to seal electronic parts, an internal die space defined at least by pots, cull portions, resin passages and cavities when an upper mold section and a lower mold section are closed, is cut off or sealed from the exterior atmosphere. Thereupon the die space is evacuated using a first evacuation by a vacuum source and a second or instantaneous evacuation by an instantaneous evacuation mechanism. The vacuum source for the first evacuation may be an active vacuum pump, while the instantaneous evacuation mechanism may be a vacuum tank that has been previously pumped down, for example. According to this method, it is possible to quickly improve the degree of vacuum in the internal die space by efficiently and reliably discharging air, moisture and gas from the internal die space to the exterior due to a synergistic action of the evacuation and the instantaneous evacuation. Consequently, the formation of voids in resin molded members is prevented.

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Kyoto, Japan

Koichi Araki