BRIEF DESCRIPTION OF THE DRAWINGS
  
    FIG. 1 is a schematic block diagram showing a casting mold making system according to an embodiment of the present invention.
  
    FIG. 2 is a graph showing the relation between the bulk density of casting sand in a receiver and the kinetic energy of casting sand blown out through blow nozzles.
  
    FIG. 3 is a graph showing the relation between the bulk density of casting sand in the receiver and the stirring resistance of a stirrer.
  
    FIG. 4 is a flowchart showing a processing procedure of a controller.