Molding machine and molding process

A molding machine for simultaneously making an upper mold and a lower mold, the machine comprising:

• a drag flask that is arranged such that the drag flask can be carried in and carried out of a site in the machine adapted to make molds;
• a matchplate mounted on an upper surface of the drag flask and having patterns on under and upper surfaces thereof;
• a lower filling frame that can be raised and lowered and having sidewalls with sand-filling ports, the lower filling frame being coupled to a lower end of the drag flask;
• a lower squeezing board that can be raised and lowered to define a lower molding space together with the drag flask and the under surface of the matchplate;
• an upper squeezing board that is fixed above and opposed to the matchplate;
• a cope flask for defining an upper molding space together with the upper surface of the matchplate and the upper squeezing board;
• a flask-setting and squeezing cylinder for raising and lowering the lower squeezing board;
• a driving mechanism that includes a pneumatic piping system and a hydraulic piping system for driving the flask-setting and squeezing cylinder using an air-on-oil system;
• and
• a controller for controlling the driving mechanism, wherein:
• a) upon the drag flask, the matchplate, the lower filling frame, and the lower squeezing board defining the lower molding space, while the matchplate, the upper squeezing board, and the cope flask define the upper molding space, the controller controls the driving mechanism to drive the flask-setting and squeezing cylinder at a low pressure;
• b) upon the lower squeezing board being raised to squeeze molding sand in the cope flask and the drag flask for simultaneously making an upper mold and a lower mold, the controller controls the driving mechanism to drive the flask-setting and squeezing cylinder at a high pressure that is increased by means of a booster cylinder;
• and
• c) upon the upper mold being removed from the pattern on the upper surface of the matchplate, while the lower mold is being removed from the pattern on the under surface of the matchplate, the controller controls the booster cylinder to stop the booster cylinder and to drive the flask-setting and squeezing cylinder at a low pressure to descend the lower squeezing board;
• and
• wherein the controller controls the driving of the flask-setting and squeezing cylinder at the low pressure to remove molds to lower the lower squeezing board such that the drag flask, the matchplate, and the lower filling frame are lowered to remove the upper mold, while they are engaged with a pair of travelling rails for stooping the lowering of the drag flask and the matchplate in a middle of the lowering movement thereof, thereby the lowering of the lower squeezing board and the lower filling frame being able to continue to remove the lower mold.