Injection device of light metal injection molding machine

An injection device of a light metal injection molding machine, comprising:

• a melter melting a material bar of light metal supplied into a melting cylinder into molten metal in the melting cylinder;
• an injector injecting the molten metal supplied from the melting cylinder into an injection cylinder with a plunger that advances and retracts in the injection cylinder;
• a connection member connecting the melter and the injector and formed with a communication path that connects inside of the melting cylinder to inside of the injection cylinder;
• an inert gas supplier supplying an inert gas;
• a first inert gas storage part housing a plunger insertion portion for inserting the plunger into the injection cylinder, and at least a part of the plunger exposed to outside of the injection cylinder, to create an atmosphere of the inert gas inside the first inert gas storage part;
• a second inert gas storage part communicating with the inside of the melting cylinder and housing a surplus of the molten metal in the melting cylinder, to create an atmosphere of the inert gas above the molten metal housed in the second inert gas storage part;
• and
• a first pressure adjustment part adjusting a pressure of the inert gas in the first inert gas storage part to a pressure equal to or less than a pressure obtained by adding a pressure, which is determined based on a value obtained by multiplying a specific gravity of the molten metal by a height difference between a highest position and a lowest position of the molten metal in a part that includes the inside of the injection cylinder and communicates with the inside of the injection cylinder, and a pressure of the inert gas in the second inert gas storage part.