Method of and apparatus for molding resin to seal electronic parts

An apparatus for molding resin to seal electronic parts, comprising:

• a die for resin molding including an upper mold section and a lower mold section arranged opposite to each other and having a plurality of pots, a plurality of cavities and a plurality of resin passages communicating said pots and said cavities with each other;
• means for supplying resin tablets into respective ones of said plurality of pots;
• means for supplying and setting electronic parts mounted on lead frames into prescribed positions in said cavities of said die;
• means for closing said die with said resin tablets in said pots and said electronic parts in said cavities, and means for heating said resin tablets for melting said resin tablets to provide melted resin;
• means for injecting said melted resin into said cavities through said resin passages, thereby sealing said electronic parts with resin;
• means for cutting off, from an exterior of said die, an internal die space portion being defined by at least said pots, said resin passages and said cavities upon closing of said die;
• first evacuation means for forcibly sucking and discharging air, moisture and gas being contained in said internal die space portion to the exterior thereby improving a degree of vacuum in said internal die space portion;
• and
• instantaneous evacuation means for forcibly sucking and discharging said air, said moisture and said gas being contained in said internal die space portion to the exterior in a short time thereby quickly improving the degree of vacuum in said internal die space portion;
• wherein said first evacuation means includes a vacuum source, and said instantaneous evacuation means includes a vacuum tank, and
• wherein said apparatus further includes a vacuum path connecting said vacuum source, said vacuum tank and said internal die space portion, a first switching valve located in a first portion of said vacuum path connecting said vacuum source and said internal die space portion, and a second switching valve located in a second portion of said vacuum path connecting said vacuum source and said vacuum tank, with said vacuum tank being in fluid communication with said internal die space portion selectively via said first and second switching valves.