The permanent mold process is a casting process where the mold is manufactured from metal instead of sand. This allows the mold to be reused to produce a large volume of castings. The molds are machined from grey iron or tool steel.
The molds are heated to approximately 500 degrees Fahrenheit and are filled using gravity pressure. The molds are coated with a ceramic coating to prevent wetting of the mold and ease of part removal.
The liquid metal solidifies quickly due to the good heat conductivity of the mold material. Both mold halves get separated and the casting is removed and the mold is ready for the next casting cycle.
The permanent mold coating needs to be replenished after several casting cycles.
The described permanent mold process is mostly used to cast aluminum alloys.
The PIAD chill casting process is an advanced permanent mold process and has been specially developed to cast pure copper and copper based alloys.