In this process, a gooseneck is used for pumping the liquid metal into the die cavity. The gooseneck is submerged into the holding furnace containing the molten metal. The gooseneck is made of grey, alloy or ductile iron or of cast steel. A plunger made of alloy cast iron, which is hydraulically operated moves up in the gooseneck to uncover the entry port for the entry of liquid metal into the gooseneck. The plunger can then develop the necessary pressure for forcing the metal into the die cavity. A nozzle at the end of the gooseneck is kept in close contact with the sprue located in the cover die.
The cycle starts with the closing of the die when the plunger is in the highest position in the gooseneck, thus facilitating the filling of the gooseneck by the liquid metal. The plunger then starts moving down to force the metal in the gooseneck to be injected into the die cavity. The metal is then held at the same pressure till it is solidified. The die is opened, and any cores if present, are also retracted. The plunger then moves back returning the unused liquid metal to the gooseneck. The casting, which is in the ejector die, is now ejected and at the same time the plunger uncovers the filling hole, letting the liquid metal from the furnace to enter the gooseneck.
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