Investment casting is an industrial process based on lost-wax casting, one of the oldest known metal-forming techniques. The term 'lost-wax casting' can also refer to modern investment casting processes.The investment shell for casting a turbocharger rotorA view of the interior investment shows the smooth surface finish and high level of detailThe completed workpiece Investment casting is an industrial process based on lost-wax casting, one of the oldest known metal-forming techniques. The term 'lost-wax casting' can also refer to modern investment casting processes.