Lost wax casting
The wax patterns is placed in a flask and covered in a refractory ceramic material, e.g. plaster. When the ceramic material solidifies, it forms the mold for casting . The plaster mold is then put in an oven and heated for several hours to a point where the wax is completely burned out.
Molten metal is poured into the cavity where the wax patterns was . When the metal has cooled and solidified the metal casting is broken out.
This maufacturing technique is also known as the lost wax process