What material is the mold of automobile engine shell made of?

Automobile engine shell, including cylinder shell, cylinder head shell and crankcase shell, the casting molds of these shells are all sand-turning molds. Before the sand mold appeared, it was a wooden mold made by a mold worker. You can visit the mold workshop of the engine factory, and you will see that these molds are placed in positions corresponding to the numbers, but when you want to pick them up and put them down, you will use the crane at the top of the workshop to lift them. The scene is spectacular and orderly.

Other parts of the engine are sand mold, aluminum alloy film and wax mold.