The term "investment" refers to the ceramic materials used to construct hollow shells into which molten metal must be poured to make a casting. The process was given the name "investment" due to the solid mold process involving a plaster-type material being poured or "invested" into a container containing small plastic patterns that appear to be a replica of the casting produced. After the plaster-like material has solidified, the model will be burned leaving an empty cavity where the metal will be poured. The process is also called 'lost wax casting', a name which derives from the wax lost during the formation of the cavity. Both names are correct, but investment casting is the older traditional name of the process and investment casting is the name of the new version of the process. The lost wax casting technique is among the oldest processes and is also among the most modern. The discovery that metals could be smelted into molds and spindles was one of the most important breakthroughs towards human civilization. Lost wax casting dates back thousands of years. Its first known use was for statues, idols, jewelry and ornaments. Natural wax was used to make the models and clay was used to make the mold. Bronze and precious metal objects have been produced using this type of method for at least 6,000 years. The most famous investment casting during the Renaissance period was that of the "four doors" in the church of San Giovanni, Italy. The doors were made by Lorenzo Ghiberti in the year 1380, the panels were cast in bronze and took 48 years to finish and some other famous examples of lost wax casting can be dated to 2000 BC from the Harappan civilization of Pakistan and Egyptian tombs (1333- 1324B.......half of the paper......of impasto to be dried in the middle. This will then be dried and a dipping process will be repeated until a certain thickness is reached. The entire design will be then placed in an oven and the wax melts leaving a hollow cavity inside the mold that exactly matches the shape of the assembly. Before melting the "skin" or shells will be fired in an oven, where the heat will burn off the remaining wax. and will prepare it. the mold for the molten metal will be poured into a shell through a funnel-shaped cup and will flow down the sprue channel and pass through the access points into the cavities of the part metal will have cooled the gates, the sprue and the parts will become a solid casting. When the casting has cooled the shell will crack. After some finishing operations, the castings, exact replicas of the wax models, are ready for shipment to the customer and for certification.