Injection-molding method and apparatus

An injection-molding apparatus including a first die, a second die, a third die, and means for moving the second and third dies, said apparatus being constructed to mold a front side molded layer to a front face of a plate-shaped member by sandwiching the plate-shaped member with the first die and the second die being closed and thereby forming a front side cavity with the front face of the plate-shaped member and the first die and filling the front side cavity with a molding material such as resin and to mold a rear side molded layer to the rear face of the plate-shaped member by replacing the second die with a third die and sandwiching the plate-shaped member with the third die and the first die and thereby forming a rear side cavity with the rear face of the plate-shaped member and the third die and filling the rear side cavity with a molding material such as resin, wherein:

• the first die includes a gate for injecting molding material into the front side cavity and the rear side cavity, said gate being adapted to face a through hole formed in the plate-shaped member;
• the second die includes a receiving face for making contact with the rear face of the plate-shaped member, and wherein the receiving face includes a pin adapted to fit in the through hole;
• and
• to replace the second die with the third die, the moving means is adapted to move the second and third dies between a facing position facing the first die and a withdrawn position away from the first die.