A mill operator's main duty is to run and monitor the machines that perform various tasks, such as cutting, drilling, milling, shaping, or polishing materials. They also have to adjust the settings, speed, and feed of the machines, as well as change the tools and parts when needed.Assist in the setup and operation of milling machines to produce parts according to specifications. Perform routine maintenance and minor repairs on milling machines to ensure optimal performance. Monitor machine operations and make adjustments as necessary to maintain quality control