EXTRUSION MOLDING MACHINE

PROBLEM TO BE SOLVED: To mold a molded product to its central part in a dense structure by a method wherein a tip of a screw vane provided around a rotary shaft is projected forward from the rotary shaft, and the projected part is cut in a recessed state along an inner face shape of an earthenware mortar wherein a tip of the rotary shaft is made its crest. SOLUTION: A tip part of a rotary shaft 3 is of a tapering off shaped cannonball type. A tip of a screw vane 2 is provided by being slightly projected forward from the rotary shaft 3. The projected part is cut in a recessed state along a peripheral surface shape of a flat cone which is arranged in a confronted state by having the tip of the rotary shaft 3 as its crest. Raw material 5 sent out with the screw vane 2 in the barrel 1 is extruded while it is rotated in a state of wrapping the rotary shaft 3 with the raw material 5, and pressurized to its center at the same time when it is separated from the tip of the rotary shaft 3.