A control method of an injection molding machine that molds a molding product including a skin layer and a core layer in a mold unit by injecting a molding material to the mold unit from a nozzle, the control method including controlling, at a starting time of an injection process, a temperature of the molding material used to form the skin layer so as to be higher than a temperature of the molding material used to form the core layer.

A feeder according to an embodiment includes: a weight-type feeder including a hopper to which a raw material is supplied, and a discharging port from which the raw material is discharged; and a volume-type feeder including a hopper to which the raw material discharged from the discharging port is supplied, and a discharging port from which the raw material is discharged. The volume-type feeder repeats the discharging of the raw material from the discharging port and the stopping of the discharging, and the weight-type feeder continuously discharges the raw material from the discharging port to the hopper during which the discharging of the raw material from the discharging port and the stopping of the discharging are performed.

A core molding apparatus and a core molding method capable of reducing the possibility of the deterioration in the calculation accuracy of the amount of supply of a raw material for a core are provided. A core molding apparatus includes: a kneading tank configured to knead a raw material for a core; a raw material supply unit configured to supply the raw material to the kneading tank; a mold configured to contain a kneaded material made of the raw material kneaded in the kneading tank and to mold the core; a piston configured to inject the kneaded material contained in the kneading tank into the mold; and a control unit configured to control an amount of supply of the raw material from the raw material supply unit to the kneading tank.