Injection-molding method and apparatus

An injection-molding method for covering a front face and a rear face of a plate-shaped member with a molded layer by injection-molding, the injection-molding method comprising the steps of:

• preparing a first die having a front side cavity face that will face the front face of the plate-shaped member and a first gate opening at the front side cavity face and a first pressure sensor communicating with the front side cavity face and preparing a second die having a rear side cavity face that will face the rear face of the plate-shaped member and a second gate opening at the rear side cavity face and a second pressure sensor communicating with the rear side cavity face;
• sandwiching the plate-shaped member with the first die and the second die and thereby forming a front side cavity with the front side cavity face of the first die and the front face of the plate-shaped member and forming rear side cavity with the rear side cavity face of the second die and the rear face of the plate-shaped member;
• injecting a molding material such as resin through the first gate into the front side cavity and injecting a molding material through the second gate into the rear side cavity;
• and
• stopping the injection of molding material into the front side cavity when a measured value of the first pressure sensor reaches a prescribed value and stopping the injection of molding material into the rear side cavity when a measured value of the second pressure sensor reaches a prescribed value, to mold front and rear side molded layers respectively in the front and rear side cavities.