Many metal and plastic parts are used in the manufacture of consumer goods. Metal and plastic machine workers put up and operate the machinery that manufacture the parts. Hundreds of thousands of machine operators in the manufacturing business labour in various stages of production, setting up machinery to generate the correct product based on designs. Machine setters setup machines for production and execute initial batch test runs, making repairs or modifications as needed to guarantee quality control. The machine is then handed over to operators, who may have to load it with metal or plastic materials or alter machine settings throughout production. They inspect the parts and do minor maintenance on a regular basis. They remove and test final products after completion, then record production quantities. Metal and plastic machine operators may specialise in one type of machine, such as: Operators of computer-controlled machine tools use robots to perform tasks on workpieces. CNC employees, or computer numerically controlled machine tool programmers, create computer programmes to control automated processes. They need greater training than other types of machine workers. Workers on extruding and drawing machines extrude thermoplastic or metal materials in the shape of tubes, rods, or hoses. Workers on cutting, punching, and press machines operate machines that saw, bend, or straighten materials. Molding, coremaking, and casting machine operators operate equipment that produce metal or thermoplastic parts or products. More than one type of cutting or forming machine tool or robot is set up or operated by many machine tool setters, operators, and tenders. Machine workers are frequently employed full-time in manufacturing facilities, working schedules that include evenings, weekends, and regular overtime. Because automation allows numerous machines to be controlled at the same time, workers can train on a range of machines and gain a diverse set of abilities. Because these personnel operate strong, high-speed machines, they normally wear safety glasses, earplugs, and steel-toed boots. Respirators are commonly used by persons working in the plastics industry who are exposed to hazardous gases or dust. Employers prefer to hire high school graduates and then train machine operators on the job.