Patent ID: 7594532

Claim:
A method of controlling the operation of an apparatus for making an upper and a lower mold, the apparatus including: a molding unit having: a cope flask and a drag flask which hold a match plate between them; an upper squeeze member, which is inserted in a space of the cope flask, which has no match plate, and which can form a molding space to make the upper mold in combination with the cope flask; and a separating means which is installed on the cope flask to separate the upper squeeze member from the match plate; an actuator having: an upper squeeze means to press the upper squeeze member against the match plate; a filling frame and a lower squeeze member, both of which together can form, in combination with the drag flask, a space to make a lower mold; and a lower squeeze means to press the lower squeeze member against the match plate; a driving unit which drives the upper and the lower squeeze means; and a conveying means having a rotating frame which can rotate upward or downward in a perpendicular plane, wherein the molding unit is moved into or out of the actuator by the rotating frame and the upper and lower squeeze members are forwarded to the match plate by the upper and lower squeeze means, the method comprising the steps of: measuring an upper squeeze force that the upper squeeze member receives from the upper squeeze means and a lower squeeze force that the lower squeeze member receives from the lower squeeze means; calculating the difference between the squeeze forces so measured; comparing the difference between the squeeze forces with a predetermined tolerance of difference between the squeeze forces; and controlling the driving unit to, based on the results of the comparison, stop or slow forward movement of the upper squeeze member or the lower squeeze member or both until the difference between the squeeze forces becomes less than the tolerance.