A sealed holding furnace with liquid metal inside is connected to the upper mold by a ceramic tube. Low air pressure is applied to the sealed furnace in order to cast. The liquid metal is sent to the mold cavity by means of a ceramic tube. When the solidification in the mold is complete, the pressure is reduced to normal and the liquid metal in the tube returns to the furnace. The mold is opened and the part is ejected.
In this method, the turbulence risk is minimized as the mold fills slowly. Since it is controlled by the PLC system, the casting speed is almost equal in every piece. Unlike free casting, it fills not from the metal surface, but from inside, it does not carry oxides and inclusions.