Molding method and molding apparatus

Abstract

A molding apparatus ( 30 ) is configured so as to form a molten metal holding space ( 41 a ) by dividing the inside of a connecting portion ( 41 ) into the molten metal holding space ( 41 a ) and a molten metal supply port-side space ( 41 b ) by closing an on-off valve ( 42 ), and pump up molten metal ( 5 ) from a molten metal furnace ( 50 ) into the molten metal holding space ( 41 a ) of the connecting portion ( 41 ) with a pump ( 40 ). Then a pressure of the molten metal ( 5 ) that has been pumped up into the molten metal holding space ( 41 a ) is reduced by a pressure-reducing portion, and the molten metal holding space ( 41 a ) inside the connecting portion ( 41 ) is communicated with a molten metal supply port ( 6 ) of an injection sleeve ( 2 ) by opening the on-off valve ( 42 ), and the molten metal ( 5 ), the pressure of which has been reduced in the molten metal holding space ( 41 a ), is supplied into the injection sleeve ( 2 ).

1 - 5 . (canceled) 
     
     
         6 . A molding method that uses a molding apparatus that is provided with a mold having a cavity, an injection sleeve that has a molten metal supply port and is communicated with the cavity, a molten metal furnace within which molten metal is stored, a connecting portion that connects the molten metal furnace to the injection sleeve by one end of the connecting portion being connected to the molten metal furnace and the other end of the connecting portion being connected to a location opposite the molten metal supply port, a pump that is arranged in the connecting portion and pumps up molten metal from the molten metal furnace, a valve that is arranged in the connecting portion, and that forms a molten metal holding space that holds the molten metal pumped up by the pump, in the connecting portion, and a pressure-reducing portion that is arranged in a portion of the connecting portion where the molten metal holding space is located, and that reduces pressure in the molten metal holding space, the molding method comprising:
 forming the molten metal holding space inside the connecting portion by closing the valve;   pumping up the molten metal from the molten metal furnace into the molten metal holding space of the connecting portion with the pump;   reducing a pressure of the molten metal pumped up into the molten metal holding space with the pressure-reducing portion;   communicating the molten metal holding space of the connecting portion with the molten metal supply port of the injection sleeve by opening the valve; and   supplying the molten metal, the pressure of which has been reduced inside the molten metal holding space, into the injection sleeve.   
     
     
         7 . The molding method according to  claim 6 , wherein the pumping up of the molten metal involves pumping up, into the molten metal holding space, molten metal of the same amount as the molten metal that is injected into the cavity. 
     
     
         8 . The molding method according to  claim 7 , wherein the reducing of the pressure of the molten metal involves stopping movement of the molten metal from the molten metal furnace to the connecting portion by operating the pump, while the pressure is being reduced. 
     
     
         9 . The molding method according to  claim 6 , further comprising:
 injecting molten metal into the cavity;   solidifying the molten metal inside the cavity;   releasing a molded article formed by the molten metal that has solidified inside the cavity from the mold; and   applying a mold release agent to an inside of the cavity,   wherein the forming of the molten metal holding space, the pumping up of the molten metal, and the reducing of the pressure of the molten metal of a next cycle are performed while one of the injecting, the solidifying, the releasing, and the applying is being performed.   
     
     
         10 . A molding apparatus comprising:
 a mold having a cavity;   an injection sleeve that has a molten metal supply port and is communicated with the cavity;   a molten metal furnace within which molten metal is stored;   a connecting portion that connects the molten metal furnace to the injection sleeve by one end of the connecting portion being connected to the molten metal furnace and the other end of the connecting portion being connected to a location opposite the molten metal supply port;   a pump that is arranged in the connecting portion and pumps up molten metal from the molten metal furnace into the connecting portion,, and supplies the molten metal into the injection sleeve via the connecting portion;   a valve that is arranged in the connecting portion, and that forms a molten metal holding space that holds the molten metal pumped up by the pump, in the connecting portion; and   a pressure-reducing portion that is arranged in a portion of the connecting portion where the molten metal holding space is located, and that reduces pressure in the molten metal holding space,   wherein the injection sleeve performs an operation of injecting the molten metal into the cavity; the molten metal holding space is formed by closing the valve; the pump pumps up the molten metal into the molten metal holding space of the connecting portion; the valve communicates the molten metal holding space of the connecting portion with the molten metal supply port of the injection sleeve by opening, and supplies the molten metal, the pressure of which has been reduced inside the molten metal holding space, into the injection sleeve.