MOLDING SAND BLOWING IN METHOD IN MOLDING MACHINE WHICH SUMULTANEOUSLY BLOW SAND INTO UPPER AND LOWER FLASKS

摘要

PROBLEM TO BE SOLVED: To accurately and stably blow and fill molding sand in the upper and lower flasks by comparing the calculated difference value of maximum pressure of compressed air supplied into the sand magazine and upper/lower blow heads with the pressure difference value stored in advance and supplying the air of higher pressure than usual into the corresponding blow head if the pressure difference is outside the allowable range. SOLUTION: Compressed air is supplied into a sand magazine 6 and to compressed air jet mechanisms 10, 10 of upper and lower blow heads 4 and 5, so that molding sand is blown and filled in upper and lower flasks 2 and 3. At that time, the maximum pressure in the upper and lower blow heads 4 and 5 and the sand magazine 6 is measured with pressure sensors 4A, 5A, and 6A, and the pressure difference between both is calculated and compared with the pressure difference value stored in advance. If the result is within the allowable range, the next blowing/filling of molding sand is continued without change, but if it is outside the range, the air of higher pressure than usual is jetted into the corresponding blow head 4 or 5.