METHOD FOR SETTING LOST FOAM PATTERN INTO MOLDING SAND

摘要

PURPOSE:To prevent the development of deformation at the time of packing molding sand without making larger than the necessary diameter and strength of a sprue, etc., for a lost foam pattern by expanding an air expanding body with the air supplied into the inner part thereof to support the lost foam pattern. CONSTITUTION:A cloth material 9 is set at lower side of a setting device 2 and fixed to a frame 3 and the lost foam pattern 1 is laid on the cloth material 9. Successively, an air supply pump is worked and the lost foam pattern 1 is supported to the frame 3 from both sides with expansion of the air expanding body 4 through an air supply passage 6. After that, the molding sand 8 is charged into a flask 13 under condition of charging a little quantity of the molding sand at the lower side thereof and the cloth material 9 at the lower side of the frame 3 is pulled out. After that, the molding sand 8 is packed up into the flask 13 from upper part while applying vibration to the flask 13 with a vibrating device 14. The lost foam pattern 1 is fixed with the molding sand 8 itself and then, the air expanding body 4 is shrunk with dead weight of the molding sand 8 to stop the supporting with the expanding body 4, and the frame 3 is shifted upward. At the time of completing the packing of the molding sand 8, the lost foam pattern 1 is surely fixed with the molding sand 8 and the deformation is not developed.