Abstract
In the air flow press molding process which is a method of green sand molding directly utilizing energy of compressed air to compact molding sand, compressed air is applied to pass through the molding sand and then the molding sand is pressed and compacted by force resulting from the fluid resistance of the air. Mechanical squeezing is subsequently adopted to make the mold density uniform. In the present work, the compacting force acting on the molding sand in the air flow process was theoretically analyzed and the result was comfirmed by the experiment. The air pressure in the mold and its effect on the compaction of molding sand were investigated in relation to the compacting force and the mold density. It was shown that the lower portion of mold, especially near the pattern plate, is densely compacted in the process of air flow. The air pressure gradient in the mold and the mold height play a fundamental role in the compaction of molding sand, however, the difference of air pressure between the upper and the lower mold surface was experimentaly found to be the practical factor that determines the degree of compaction of molding sand.
