A roller or rolling mill is a machine used in manufacturing, such as metalworking or plastic manipulation, to flatten or shape materials. The responsibilities of a rolling mill operator are the setup and operation of equipment to form metal or other materials into a plate, sheet, flatware, rod, or other specific manufacturing shape using techniques such as hot or cold rolled steel. Other duties involve machine maintenance and quality control of products to ensure there is no cracking, defects, or deformities. Qualifications to become a rolling mill operator vary but often include a high school diploma or GED certificate and on-the-job training.