Principle of low pressure casting

Low pressure casting is a casting method between pressure casting and gravity casting. In the sealed crucible containing liquid metal, pass compressed air to pressurize the surface of liquid metal in the crucible, so that the liquid metal is squeezed into the mold cavity from bottom to top along the riser. After the liquid metal fills the mold cavity (metal mold casting), increase the air pressure, maintain the liquid level pressure until the casting is completely solidified, and then release the pressure in the crucible (exhaust), The non solidified liquid metal in the riser and sprue falls back into the crucible, that is, a low-pressure casting process is completed.