Abstract: A synthetic resin molding mold assembly, is provided for rapidly heating a cavity surface without suffering from any temperature variation in the cavity surface when a temperature of the cavity surface increases; this condition is not affected by a contour of the cavity surface; and, may prevent any weld line from occurring without prolonging a molding cycle time. A mold insert is employed that is divided into an insert front piece with the cavity surface and an insert rear piece without the cavity surface. A fluid passage is formed to pass through the front piece in the vicinity of the cavity surface and extends from a rear surface of the rear piece to pass there-through toward the cavity surface, receives an electric heater therein, and is then closed with the rear piece to dispose the heater in a deepest portion of the fluid passage.

Abstract: A synthetic resin molding mold assembly, is provided for rapidly heating a cavity surface without suffering from any temperature variation in the cavity surface when a temperature of the cavity surface increases; this condition is not affected by a contour of the cavity surface; and, may prevent any weld line from occurring without prolonging a molding cycle time. A mold insert is employed that is divided into an insert front piece with the cavity surface and an insert rear piece without the cavity surface. A fluid passage is formed to pass through the front piece in the vicinity of the cavity surface and extends from a rear surface of the rear piece to pass there-through toward the cavity surface, receives an electric heater therein, and is then closed with the rear piece to dispose the heater in a deepest portion of the fluid passage (see FIG. 1).