Abstract: A method and system using a molding apparatus with frames by which the amount of molding sand that overflows the molding apparatus and that must be taken out of a mold that is prepared by a molding operation is minimized, and by which the density of the mold within a frame is substantially uniform. The molding sand filling cavity is defined by a pattern plate, a molding frame that can be put on the pattern plate, a filling frame that can be put on the molding frame, and a covering apparatus having a plurality of squeezing feet. The squeezing feet can enter the filling frame and can be temporarily held at certain positions where certain distances are kept between the lower ends of the squeezing feet and surfaces of the patterns on the pattern plate that are opposed to the lower ends. Molding sand is supplied to the molding sand filling cavity. Then, the molding sand is compressed by the squeezing feet.

Abstract: A method for compacting molding sand in a mold space defined by a pattern plate, which is fixed in a horizontal position when the molding sand is compacted, a leveling frame disposed for vertical sliding movement around the outer periphery of the pattern plate, a frame member disposed for vertical movement above the leveling frame, and a filling frame disposed for vertical movement above the frame member. The method comprises the steps of feeding molding sand into the mold space, primarily compacting the molding sand in the mold space from above by compacting means while at least the leveling frame is being set so that it cannot be lowered, and secondarily compacting the molding sand in the mold space from above by the compacting means while the leveling frame, the frame member, and the filling frame are set so that these elements can be lowered.

Abstract: A process for preparing a molding sand for a green sand mold is provided. The process comprises the step of drying under a reduced pressure of 0 to 0.3 atm for 0.5 to 30 seconds a green molding sand obtained by kneading silica sand, clay, and water, to dry the clay superficial part and to retain in a moist state the clay deeper part on the silica sand core part in each particle of the molding sand. The molding sand prepared by this process has enhanced flowability. Furthermore, the sand mold prepared from the molding sand has sufficient strength.