Consider the parts of a toaster, such as the metal or plastic housing or the lever that lowers the toast. These parts, and many other metal and plastic products, are produced by machine setters, operators, and tenders—metal and plastic. In fact, machine operators in the metalworking and plastics industries play a major role in producing most of the consumer products on which we rely daily.
In general, these workers can be separated into two groups—those who set up machines for operation and those who operate the machines during production. Setup workers prepare the machines prior to production, perform initial test runs producing a part, and may adjust and make minor repairs to the machinery during its operation. Operators and tenders primarily monitor the machinery during its operation; sometimes they load or unload the machine or make minor adjustments to the controls. Many workers both set up and operate equipment. Because the setup process requires an understanding of the entire production process, setters usually have more training and are more highly skilled than those who simply operate or tend machinery. As new automation simplifies the setup process, however, less skilled workers also are increasingly able to set up machines for operation.
Setters, operators, and tenders usually are identified by the type of machine with which they work. Some examples of specific titles are drilling- and boring-machine toolsetters, milling- and planing-machine tenders, and lathe- and turning-machine tool operators. Job duties usually vary with the size of the firm and the type of machine being operated. Although some workers specialize in one or two types of machinery, many are trained to set up or operate a variety of machines. Increasing automation allows machine setters to operate multiple machines simultaneously. In addition, newer production techniques, such as team-oriented "lean" manufacturing, require machine operators to rotate between different machines. Rotating assignments results in more varied work, but also requires workers to have a wider range of skills.
Machine setters, operators, and tenders—metal set up and tend machines that cut and form all types of metal parts. Setup workers plan and set up the sequence of operations according to blueprints, layouts, or other instructions. Often this involves loading a computer program with instructions into the machine's computer controls. On all machines, including those with computer controls, setup workers respond to problems during operation by adjusting the speed, feed and other variables. They also choose the proper coolants and lubricants and select the instruments or tools for each operation. Using micrometers, gauges, and other precision measuring instruments, setup workers compare the completed work within the required tolerances.
Although there are many different types of metalworking machine tools that require specific knowledge and skills, most operators perform similar tasks. Whether tending grinding machines that remove excess material from the surface of solid piece of metal or presses that extrude molten metal through a die to form wire, operators usually perform simple, repetitive operations that can be learned quickly. Typically, these workers place metal stock in a machine on which the operating specifications have already been set. They watch one or more machines and make adjustments to the machines based on either reading from computers and gauges or measuring the resulting product. Regardless of the type of machine they operate, machine operators usually depend on more skilled and experienced setup workers for major adjustments when the machines are not functioning properly.
Machine setters, operators, and tenders—plastic set up and tend machines that transform plastic compounds—chemical-based products that can be produced in powder, pellet, or syrup form—into a wide variety of consumer goods such as toys, tubing, and auto parts. These products are manufactured by various methods, of which injection molding is the most common. The injection-molding machine heats and liquefies a plastic compound and forces it into a mold. After the part has cooled and hardened, the mold opens and the part is released. Many common kitchen products are produced with this method. To produce long parts, such as pipes or window frames, an extruding machine usually is used. These machines force a plastic compound through a die that contains an opening with the desired shape of the final product. Blow molding is another common plasticsworking technique. Blow-molding machines force hot air into a mold that contains a plastic tube. As the air moves into the mold, the tube is inflated to the shape of the mold, and a plastic container is formed. The familiar 2-liter soft-drink bottles are produced by this method.
Work environment. Most machine setters, operators, and tenders—metal and plastic work in areas that are clean, well lit, and well ventilated. Nevertheless, many operators require stamina, because they are on their feet much of the day and may do moderately heavy lifting. Also, these workers operate powerful, high-speed machines that can be dangerous if strict safety rules are not observed. Most operators wear protective equipment, such as safety glasses and earplugs, to protect against flying particles of metal or plastic and against noise from the machines. However, many modern machines are enclosed, minimizing the exposure of workers to noise, dust, and lubricants used during machining. Other required safety equipment varies by work setting and machine. For example, those in the plastics industry who work near materials that emit dangerous fumes or dust must wear face masks or self-contained breathing apparatus.
Overtime is common during periods of increased production for most machine setters, operators, and tenders—metal and plastic, but they usually work a 40-hour week. Because many metalworking and plastics working shops operate more than one shift daily, some operators work nights and weekends.
| 1. | Dress grinding wheels, according to specifications. |
| 2. | Monitor machine operations to determine whether adjustments are necessary; stop machines when problems occur. |
| 3. | Inspect, feel, and measure workpieces to ensure that surfaces and dimensions meet specifications. |
| 4. | Set up and operate grinding or polishing machines to grind metal workpieces such as dies, parts, and tools. |
| 5. | Remove finished workpieces from machines and place them in boxes or on racks; set aside pieces that are defective. |
| 6. | File or finish surfaces of workpieces, using prescribed hand tools. |
| 7. | Select and mount grinding wheels on machines, according to specifications, using hand tools and applying knowledge of abrasives and grinding procedures. |
| 8. | Perform basic maintenance, such as cleaning and lubricating machine parts. |
| 9. | Remove and replace worn or broken machine parts, using hand tools. |
| 10. | Compute numbers, widths, and angles of cutting tools, micrometers, scales, and gauges, and adjust tools to produce specified cuts. |
| 11. | Study blueprints or layouts of metal workpieces to determine grinding procedures, and to plan machine setups and operational sequences. |
| 12. | Turn valves to direct flow of coolant against cutting wheels and workpieces during grinding. |
| 13. | Fit parts together in preassembly to ensure that dimensions are accurate. |
| 14. | Inspect dies to detect defects, assess wear, and verify specifications, using micrometers, steel gauge pins, and loupes. |
| 15. | Duplicate workpiece contours, using tracer attachments. |
| 16. | Straighten workpieces and remove dents, using straightening presses and hammers. |
| 17. | Attach workpieces to grinding machines, then form specified sections and repair cracks, using welding or brazing equipment. |
| 18. | Place workpieces in electroplating solutions or apply pigments to surfaces of workpieces to highlight ridges and grooves. |
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