Using Industrial Hydraulics |
Applications of Computer-Aided Manufacturing
Numerical control tool programmers, also called computer numerical control tool programmers, develop programs that enable machine tools to produce parts automatically. These precisely made parts are used in automobiles, airplanes, industrial machinery, and other durable goods. There are approximately 143,000 numerical control programmers and operators in the United States.
One of the earliest attempts to automate machinery occurred in the early 1700s, when a system of punched cards was used to control knitting machines in England. Holes in punched cards controlled mechanical linkages, which directed yarn colors and allowed various patterns to be woven into a piece of material. Automated machinery did not progress much further, though, until the computer was developed in the late 1940s.
The first use of numerical control (NC) was in 1947. John Parsons, owner of a helicopter rotor blade manufacturing company, experimented with regulating milling machinery through numerical control. He discovered that In 1952, they built the first numerically controlled machine tool. Shortly afterward, Giddings and Lewis, a large machine tool builder, built an NC profiling mill.
By 1958, other companies followed with NC machine tools of their own. Early NC tools used paper tapes to program machines. Machine commands were standardized and assigned numerical codes. These codes were then sequenced in the order in which the machine was to perform various operations. After these codes were punched onto a paper tape, a machine operator loaded the tape into a tape reader, loaded raw material, and started the machine. The machine ran automatically. As numerical control technology evolved, plastic tapes replaced paper, and magnetic spots rather than holes were used to represent codes. Unfortunately, this form of numerical control did not handle changes well; a whole new tape had to be created when process modifications were required. This was a slow and tedious process.
By the 1980s, computer numerical control (CNC) began to replace older NC methods. CNC programmers write computer programs to sequence the various steps a machine needs to complete. Many machines now have computers or microprocessors built into them.
Programmers can easily revise the sequence of operations or other elements. In addition, these programs can store information about the machine tool operation (such as number and dimensions of parts made), request additional raw materials, and record maintenance requirements.
Another advancement in numerical control is direct numerical control, a process in which several machines are controlled by a central computer. This eliminates the need for individual machine control units and gives programmers more flexibility for modification and control. The use of CNC machine tools has grown steadily during the last decade and is expected to increase in the future. New applications, such as versatile machining centers, are being developed that allow machines to provide multiple capabilities. Engineers and researchers continue to explore ways to improve the speed, precision, and versatility of machine processes through the use of numerical control and other automated processes.
Numerical control tool programmers write the programs that direct machine tools to perform functions automatically. Programmers must understand how the various machine tools operate and know the working properties of the metals and plastics that are used in the process.
Writing a program for a numerically controlled tool involves several steps. Before tool programmers can begin writing a program, they must analyze the blueprints of whatever function is to be performed or item to be made. Programmers then determine the steps and tools needed. After all necessary computations have been made, the programmers write the program.
Programmers almost always use computers to write the programs, using computer-aided design (CAD) systems. The growing use of this technology has increased productivity, translating designs directly into machine instructions without the need for coded programming. CAD systems allow programmers to more easily modify existing programs for other jobs with similar specifications. To ensure that a program has been properly designed, tool programmers often perform a test or trial run. Trial runs help ensure that a machine is functioning properly and that the resulting product is according to plan. However, because problems found during a trial run could damage expensive machinery and tools, tests are increasingly done using computer simulations.
High school courses in computer science, algebra, geometry, and English provide the basics needed to become a CNC programmer. More specific courses in blueprint reading, drafting, and computer-aided design are also useful. In addition, shop classes in metalworking can provide an understanding of machinery operations.
Employers prefer to hire skilled machinists or tool operators to work as CNC programmers. Workers are usually trained through formal apprenticeships or postsecondary programs, or informally on the job. Apprenticeship programs usually last four years and include training in. machine operations, program writing, computer-aided design and manufacturing, and analysis of drawings and design data. Classes include blueprint reading and drawing, machine tools, industrial mathematics, computers, and operation and maintenance of CNC machines.
Formal apprentice programs are becoming rare as more programmers receive training through community or technical colleges. Associate’s degrees are available in areas such as manufacturing technology and automated manufacturing systems. Typical classes include machine shop, numerical control fundamentals, technical mechanics, advanced NC programming, introduction to robotic technology, and computer-assisted manufacturing.
For specialized types of programming, such as in aerospace or shipbuilding, employers often require a four-year degree in engineering in addition to technical skills and work experience.
Numerical control tool programmers must have an understanding of machine tool operations, possess analytical skills, and show a strong aptitude for mathematics and computers. They also need good written and verbal communication skills to instruct machine operators and other engineers how to use and adjust programs. In addition, as new developments in technology bring new computer languages, methods, and equipment, numerical control tool programmers must be willing to learn new skills. Employers generally arrange and pay for courses to keep their programmers up-to-date on the latest trends and technology.
If you are interested in a career as a tool programmer, you can test your interest and aptitude by taking shop and other vocational classes. You can also visit firms that employ numerical control tool programmers and talk directly with them to gain practical information about their jobs. Summer or part-time work at manufacturing firms and machine shops is a great way to find out more about the job and gain hands-on experience.
Most numerical control tool programmers work in cities where factories and machine shops are concentrated, such as those located in the Northeast, Midwest, and West Coast regions. They work for many types and sizes of businesses. Among the largest employers are the aerospace and automobile industries and other manufacturers of durable goods. Approximately 143,000 numerical-control programmers and operators are employed in the United States.
Tool programming generally is not considered an entry-level job; most employers prefer to hire skilled machinists or those with technical training. Students who want to enter the job directly from formal training at a college or technical school can find job assistance through their school’s career services office. Prospective programmers also may learn of openings through state and private employment offices, newspaper ads, and the Internet.
Advancement opportunities are somewhat limited for tool programmers. Employees may advance to higher-paying jobs by transferring to larger or more established manufacturing firms or shops. Experienced tool programmers who demonstrate good interpersonal skills and managerial ability can be promoted to supervisory positions.
The median hourly salary for numeric control tool programmers was $20.42 (or $42,480 annually) in 2006, according to the U.S. Department of Labor. The lowest paid 10 percent earned less than $13.11 (or $27,260 annually), and the highest paid 10 percent earned more than $31.85 (or $66,260 annually).
Benefits vary but may include paid vacations and holidays, personal leaves, medical, dental, vision, and life insurance, retirement plans, profit sharing, and tuition assistance programs.
Numerical control tool programmers generally work a 40-hour week, although overtime is common during peak periods. To justify the costly investments in machinery, some employers extend hours of operation, requiring CNC programmers to work evening and weekend shifts.
Programmers work in comfortable office surroundings, set apart from the noisier, more hazardous shop floor. Their work is more analytical and, as a result, less physically demanding than the work of machinists and other tool operators.
The employment of numerical control tool programmers is expected to decline through 2014, according to the Occupational Outlook Handbook. Initially, employment of CNC programmers was made possible by the introduction of new automation, but recent techno logical advancements are reducing the demand for such workers. Newer, user-friendly technology now allows some programming and minor adjustments to be made on the shop floor by machinists and machine operators rather than by skilled CNC programmers. Fewer programmers are needed to translate designs into CNC machine tool instructions, as new software is able to do this automatically. Employment is also influenced by economic cycles. As the demand for machined goods falls, programmers involved in this production may be laid off or forced to work fewer hours.
However, employers continue to have difficulty finding workers with the necessary skills and experience to fill open programmer positions. Additionally, many openings will arise as numerical control tool programmers leave jobs to retire or switch occupations.
FOR MORE INFORMATION
For information on apprenticeships, contact the UAW.
International Union, United Automobile, Aerospace, and Agricultural Implement Workers of America (UAW)
8000 East Jefferson Avenue
Detroit, MI 48214-2699
For information on careers and educational programs, contact the following organizations:
National Tooling & Machining Association
9300 Livingston Road
Fort Washington, MD 20744-4914
Precision Machined Products Association
6700 West Snowville Road
Brecksville, OH 44141-3212