Vacuum Casting (Negative Pressure Sealed Casting, Reduced Pressure Casting or V Process Casting) uses dry sand and negative pressure to form the casting molds. Vacuum negative pressure casting is one type of dry sand casting and requires the use of air extraction equipment to extract the air inside the casting mold, and then use the pressure difference between the inside and outside of the mold to cover the heated plastic film on the patterns and the templates. The casting mold will become strong enough to withstand the molten metal during casting. After obtaining the vacuum casting mold, fill the sand box with dry sand without binder, and then seal the top surface of the sand mold with the plastic film, followed by vacuum to make the sand firm and tight. After that, remove the mold, put the sand cores, close the mold to make everthing ready for pouring. Finally, the casting is obtained after the molten metal is cooled and solidified.