Using Industrial Hydraulics |
Applications of Computer-Aided Manufacturing
Plastics products manufacturing workers mold, cast, and assemble products made of plastics materials. The objects they make include dishes, signs, toys, insulation, appliance parts, automobile parts, combs, gears, bearings, and many others.
Thermoplastics—plastics that soften with heat and harden when cooled— were invented in France in 1828. In the United States in 1869, a printer named John Wesley Hyatt attempted to create an alternative material to supplement ivory in billiard balls. He experimented with a mixture of cellulose nitrate and camphor, creating what he called celluloid. His invention, patented in 1872, brought about a revolution in production and manufacturing. By 1892, over 2,500 articles were being produced from celluloid. Among these inventions were piano keys, false teeth, and the first movie film. Celluloid did have its drawbacks. It could not be molded and it was highly flammable.
It was not until 1909, however, that the Belgian-American chemist Leo H. Baekeland produced the first synthetic plastic. This product replaced natural rubber in electrical insulation and was used for phone handsets and automobile distributor caps and rotors. It is still used today. Other plastics materials have been developed steadily. The greatest variety of materials and applications, however, came during World War II, when the war effort brought about a need for innovation in clothing, consumer goods, transportation, and military equipment.
Today, plastics manufacturing is a major industry whose products play a vital role in many other industries and activities around the world. It is difficult to find an area of our lives where plastics do not play some role. Major users of plastics include the electronics, packaging, aerospace, medical, and housing and building industries, The plastics industry also provides the makings for a large variety of consumer goods. Appliances, toys, dinnerware, luggage, and furniture are just a few products that require plastics.
Plastics products manufacturing workers have always been needed in the production of plastic. Their job responsibilities and skills have changed and grown more specialized as new production processes and materials have come into widespread use.
Plastics are usually made by a process called polymerization, in which many molecules of the same kind are combined to make networks of giant particles. All plastics can be formed or shaped; some become pliable under heat, some at elevated room temperatures. When treated, some plastics become hard, some incredibly strong, and some soft like putty. Plastic objects are formed using several different methods. Each method produces a different type of plastic. In compression molding, plastics compounds are compressed and treated inside a mold to form them. In injection molding, liquid plastic is injected into a mold and hardened. Blow molding is like glass blowing—air is forced into plastic to make it expand to the inner surface of a mold. In extrusion, hot plastic is continuously forced through a die to make products like tubing. Laminating involves fusing together resin-soaked sheets, while the calendar process forms sheets by forcing hot plastic between rollers. Finally, in fabrication, workers make items out of solid plastic pieces by heating, sawing, and drilling.
Marvin Griggs works for a company called Centro, in Springdale, Arkansas. “We’re a rotational molder for plastic products,” Griggs says. “We make custom parts for companies like John Deere. We don’t produce our own product. They send the mold, we build the parts.” Griggs is part of a four-person crew running one of the machines. The machine operator and assistant operator pour resin into the molds, which is then placed into the oven, and then the cooler. They open the molds and remove and inspect the part for warping or some other defect. The trimmer then trims the line, cut ting off the plastic flange. “If the part needs holes cut into it, or fixtures put in it,” Griggs says, “they pass it down to me.” The tools he uses include pneumatic hand tools, routers, and a large tank. “The parts are dunk-tested to make sure they’re sealed, and there are no holes. We have a tight quality control system.”
While plastics compounds may be mixed in plastics-materials plants, plastics manufacturers sometimes employ blenders, or color mixers, and their helpers to measure, heat, and mix materials to produce or color plastic materials. Grinding-machine operators run machines that grind particles of plastics into smaller pieces for processing. Pilling-machine operators take plastics powder and compress it into pellets or biscuits for further processing. Other workers (plastic form makers and plastics patternmakers) are responsible for making the molds and patterns that are used to determine the shape of the finished plastics items. Foam-machine operators spray thermoplastic resins into conveyor belts to form plastic foam. Many plastics products plants make goods according to clients’ specifications. When this is the case, job setters, using their knowledge of plastics and their properties, adjust molding machines to clients’ instructions. They make such adjustments as changing the die through which the plastic flows, adjusting the speed of the flow, and replacing worn cutting tools when necessary. Then the machine is ready to accept the plastic and produce the object.
Injection molders operate machines that liquefy plastic powders or pellets, inject liquid plastic into a mold, and eject a molded product. Compact discs, toys, typewriter keys, and many other common products are made by injection molding. Injection workers set and observe gauges to determine the temperature of the plastic and examine ejected objects for defects.
One common plastic is polystyrene, which when molded using heat and pressure makes cast foam products such as balls, coolers, and packing nests. Polystyrene-bead molders operate machines that expand these beads and mold them into sheets of bead board. Polystyrene-molding-machine tenders run machines that mold pre-expanded beads into objects. At the end of the molding cycle, they lift the cast objects from the molds and press a button to start the machine again.
Extruder operators and their helpers set up and run machines that extrude thermoplastics to form tubes, rods, and film. They adjust the dies and machine screws through which the hot plastic is drawn, adjust the machine’s cooling system, weigh and mix plastics materials, empty them into the machine, set the temperature and speed of the machine, and start it.
Blow-molding-machine operators run machines that mold objects such as bleach bottles and milk bottles by puffing air into plastic to expand it. Compression-molding-machine operators run machines that mold thermosetting plastics into hard plastic objects. Thermo setting plastics are those that harden because of a chemical reaction rather than by heating and cooling.
Casters make similar molded products by hand. Strippers remove molded items from molds and clean the molds. Some molded products must be vacuum cured and baggers run machines that perform this task.
Plastic sheeting is formed by calender operators, who adjust the temperature, speed, and roller position of machines that draw plastic between rollers to produce sheets of specified thickness. Stretch-machine operators stretch plastic sheets to specified dimensions. Pre-form laminators press fiberglass and resin-coated fabrics over plaster, steel, or wooden forms to make plastic parts for boats, cars, and airplanes.
Other common plastics products are fiberglass poles and dowels. Fiberglass-dowel-drawing-machine operators mount dies on machines, mix and pour plastics compounds, draw fiberglass through the die, and soak, cool, cure, and cut dowels. Fiberglass tube molders make tubing used in fishing rods and golf club shafts.
Plastics that are not molded may be cut into shapes. Shaping-machine operators cut spheres, cones, blocks, and other shapes from plastic foam blocks. Pad cutters slice foam rubber blocks to specified thicknesses for such objects as seat cushions and ironing board pads.
Many products undergo further processing to finish them. Foam-gun operators reinforce and insulate plastic products such as bathtubs and auto body parts by spraying them with plastic foam. Plastic-sheet cutters use power shears to cut sheets, following pat terns glued to the sheets by pattern hands. Sawyers cut rods, tubes, and sheets to specified dimensions. Trimmers trim plastic parts to size using a template and power saw. Machine finishers smooth and polish the surface of plastic sheets. And plastics heat welders use hot-air guns to fuse together plastic sheets.
Hand finishers trim and smooth products using hand tools and sandpaper. Buffers remove ridges and rough edges from fiberglass or plastic castings. Sponge buffers machine-buff the edges of plastic sponges to round them, and pointing-machine operators round the points on the teeth of plastic combs. Edge grinders tend machines that square and smooth edges of plastic floor tile.
Assemblers and laminated plastics assemblers and gluers assemble pieces to form certain products. These may include skylights and wet suits. Plastics inspectors inspect and test finished products for strength, size, uniformity, and conformity to specifications.
Experienced workers supervise plastics-making departments, and the industry also employs unskilled workers such as laborers to help haul, clean, and assemble plastics materials, equipment, and products.
If you are interested in the plastics products manufacturing field, take courses in mathematics, chemistry, physics, computer science, shop, drafting, and mechanical drawing. English and speech classes will help build good communication and interpersonal skills.
Most employers of plastics products manufacturing workers require applicants have a high school diploma. You will learn most of your skills on the job. In extrusion plants, trainees can become Class I extruders after about three months. Other jobs require training from one to 12 months.
Applicants with some knowledge of chemistry, mathematics, physics, drafting, industrial technology, or computer science have a better chance of being hired. Some colleges offer associate’s or bachelor’s degrees in plastics technology. Job seekers with these degrees have a definite competitive edge and may also advance more quickly. Another training option is to participate in an apprenticeship program. Apprenticeships provide experience and a chance to explore the field. Apprenticeships in tool and die making for plastics last four or five years and teach through classroom instruction and on-the-job training. A high school education is normally a prerequisite for an apprenticeship.
Certification or Licensing
Certification is not required of plastics technicians, but the National Certification in Plastics program is available through the Society of the Plastics Industry (SPI). As industry equipment becomes more complex, employers may prefer to hire only certified technicians. To become a certified operator, you will take an exam in one of four areas: blow molding, extrusion, injection molding, or thermoforming. The exam is geared toward skilled employees such as machine operators, process technicians, setup technicians, and supervisors.
You must have mechanical aptitude and manual dexterity to work well with tools and various materials. Lifting equipment and materials takes some strength, and workers who operate machines stand much of the time. You must be able to work well with others and follow oral and written directions, and you must be precise and organized in your work. “I’m really particular about my work from being in construction for six years,” Marvin Griggs says. “I pay really close attention to detail.”
Many high schools are beginning to offer vocational programs, and other apprenticeship opportunities, for those interested in becoming technicians; some of these programs have courses geared specifically toward preparation for the plastics industry. SPI is currently involved in providing career direction to young people interested in the plastics industry. Contact SPI (http://www.plasticsindustry.org) for career and industry information. You can also learn about the industry by reading trade magazines such as Modern Plastics (http://www.modplas.com) or Plastics News (http://www.plasticsnews.com).
Major plastics employers in the United States include DuPont, General Motors, and Owens Corning. Some of the top thermoforming companies are in Illinois: Pactiv Corporation, Solo Cup Company, and Ivex Packaging LLC are a few of them. Michigan has some of the top injection molding companies, including Lear Corporation and Venture Industries Corporation, but large plastics companies are located all across the country.
After receiving your high school diploma, you should apply directly to the personnel departments of plastics plants in the area in which you wish to work, Newspaper ads may list openings in the industry, and state employment agencies may also provide leads. The Web site http://www.polysort.com features a virtual job fair that offers free access to job listings in the plastics industry.
In the plastics industry, advancement comes with experience, skill, and education. Because plants like to teach workers their own methods, and because skilled plastics workers are scarce, most plastics companies promote workers from within to fill more responsible and higher paying jobs. Plastics workers who understand machine setup and the properties of plastics advance more quickly than those limited to machine operations.
Workers who pursue associate’s or bachelor’s degrees in plastics technology have the best chances for advancement. With advanced training and experience, some plastics workers may become plastics engineers or mold designers. Others may move into supervisory, management, or sales and marketing positions. Apprenticeships, such as in tool and die manufacturing, may also lead to more highly paid production work.
According to the U.S. Department of Labor, earnings for material handlers in the plastics industry vary widely, depending on the job. Median earnings in 2006 ranged from of $12.29 per hour (about $25,563 annually) or less for molding, core-making, and casting machine setters, tenders, and operators, to $20.22 per hour (about $42,058 annually) or more for model makers. Entry-level jobs may pay as low as $8 per hour or $16,640 per year. In addition to salary, many employers offer medical and dental benefits, life insurance, paid sick leave, personal and vacation days, and retirement plans. Employees may also be able to participate in profit-sharing plans.
Most plastics industry workers work 40 hours per week. Because plants operate on three shifts, entry-level workers may work nights and move to day shifts as they gain experience and seniority. Plastics plants are generally safe, well lighted and ventilated, and modern. Workers must observe safety precautions when working around hot machines and plastics, sharp machine parts, and electrical wiring, and when sawing, cutting, or drilling plastics parts. Plastics work, however, is not usually strenuous. Workers use machines to lift heavy dies and other equipment.
As with most production work, jobs in the plastics industry often demand a fair amount of repetition. Workers who need great variety in their jobs may not enjoy production work. Plastics plants tend to be smaller than many other types of factories so a sense of teamwork often develops among the production workers. Such camaraderie can lead to increased job satisfaction and enjoyment, “There are some safety issues,” Marvin Griggs says, “working with power tools.” But he hasn’t encountered too many negatives since taking the job, despite the many hours on his feet and being restricted to certain areas most of the day. He benefits from a retirement plan and profit sharing and has an employer who makes an effort to get to know the members of the company.
Increased competition in foreign markets and the introduction of laborsaving technology will reduce opportunities for plastics products manufacturing workers. As a result, the U.S. Department of Labor predicts that employment for workers in this field will grow more slowly than the average for all occupations through 2014—although employment outlooks vary by occupation. Multiple machine tool operators and plastics-molding, core-making, and casting machine operators should enjoy good job prospects in the next several years. Occupations that may experience a decline in employment include grinding-machine operators (due to automation); blenders; cutting, punching, and press machine setters, operators, and tenders; and color mixers.
FOR MORE INFORMATION
The Plastics Division of the American Chemistry Council offers a great deal of information about the plastics industry and maintains an informative Web site.
Plastics Division of the American Chemistry Council
1300 Wilson Boulevard
Arlington VA 22209-2323
For information about scholarships, seminars, and training, contact:
Plastics Institute of America
UMass-Lowell Campus, Wannalancit Center
600 Suffolk Street
CVTP, 2nd Floor South
Lowell, MA 01854-3643
For information on careers, college programs, and certification, contact:
Society of the Plastics Industry
1667 K Street, NW, Suite 1000
Washington, DC 200064605
For information about certification, visit the following Web site provided by the Society of the Plastics Industry:
National Certification in Plasticshttp://www.certifyme.org