MACHINIST / TOOL PROGRAMMER
Before they machine a part, machinists must carefully plan and prepare the operation. These workers first review blueprints or written specifications for a job. Next, they calculate where to cut or bore into the workpiece, how fast to feed the metal into the machine and how much metal to remove. They then select tools and materials for the job, plan the sequence of cutting and finishing operations, and mark the metal stock to show where these cuts should be made.
After this layout work is completed, machinists perform the necessary machining operations. They position the metal stock on the machine tool—drill presses, lathes, milling machines, or others—set the controls, and make the cuts. During the machining process, they must constantly monitor the feed and speed of the machine. Machinists also ensure that the workpiece is being properly lubricated and cooled because the machining of metal products generates a significant amount of heat.
Some machinists, often called production machinists, may produce large quantities of one part, especially parts requiring complex operations and great precision. For unusually sophisticated procedures, expensive machinery is used. Usually, however, large numbers of parts requiring more routine operations are produced by metalworking and plastics-working machine operators. Other machinists do maintenance work—repairing or making new parts for existing machinery. To repair a broken part, maintenance machinists may refer to blueprints and perform the same machining operations that were needed to create the original part.
Increasingly, the machine tools used to produce metal parts are computer numerically-controlled (CNC)—that is, they contain computer controllers that direct the machine's operations. The controller "reads" a program—a coded list of the steps necessary to perform a specific machining job—and runs the machine tool's mechanisms through the steps. The introduction of CNC machine tools has changed the nature of the work of machinists. These machines enable machinists to be more productive and to produce parts with a level of precision that is not possible with traditional machining techniques. Furthermore, because precise movements are recorded in the program, they allow this high level of precision to be consistently repeated. It also allows various functions to be performed with one setup, reducing the need for additional, labor-intensive setups.
The quality of the products these machines produce depends largely on the programs, which may be produced by machinists or by tool programmers. Tool programmers begin as machinists do—by analyzing blueprints, computing the size and position of the cuts, determining the sequence of machine operations, selecting tools, and calculating the machine speed and feed rates. They then write the program in the language of the machine's controller and store it. Skilled machinists may also do programming. In fact, as computer-aided manufacturing (CAM) software becomes more user-friendly and CNC machines are more widely used, machinists are increasingly expected to perform this function (see also computer programmer under Information Technology).
Machinists may work alone or with tool programmers to check new programs to ensure that machinery will function properly and the output will meet specifications. Because a problem with the program could damage the costly machinery and cutting tools, computer simulations may be used instead of a trial run to check the program. If errors are found, the program must be changed and retested until the problem is resolved. In addition, growing connectivity between computer-aided design software and CNC machine tools is raising productivity by automatically translating designs into instructions which are understood by the computer controller on the machine tool. These new CAM technologies enable programs to be more easily modified for use on other jobs with similar specifications, thereby reducing the time and effort.
Most machine shops are well lit and ventilated. Nevertheless, working around high-speed machine tools presents certain dangers, and workers must follow safety precautions. Machinists must wear protective equipment such as safety glasses to shield against bits of flying metal and earplugs to protect against machinery noise. They must also exercise caution when handling hazardous coolants and lubricants. The job requires stamina because machinists stand most of the day and may lift moderately heavy workpieces.
Some tool programmers work in offices that are near, but separate from the shop floor. These work areas are usually clean, well lit and free of machine noise.
Most machinists and tool programmers work a 40-hour week. Evening and weekend shifts are becoming more common as companies justify investments in more expensive machinery by extending their hours of operation. Overtime is common during peak production periods.
Persons interested in becoming machinists or tool programmers should be mechanically inclined, able to work independently, and able to do highly accurate work that requires concentration and physical effort.
A high school or vocational school education, including mathematics, blueprint reading, metalworking and drafting, is generally a prerequisite for becoming a machinist or tool programmer. A basic knowledge of computers and electronics is helpful because of the increased use of computer-controlled machine tools. Experience with machine tools also is extremely important. In fact, many entrants to these occupations have previously worked as machine tool operators or setters.
Machinist training varies from formal apprenticeship and postsecondary programs to informal on-the-job training. Apprentice programs consist of shop training and related classroom instruction. In shop training, apprentices learn filing, handtapping and dowel fitting, as well as the operation of various machine tools. Classroom instruction includes math, physics, blueprint reading, mechanical drawing and shop practices. In addition, as machine shops have increased their use of computer-controlled equipment, training in the operation and programming of CNC machine tools has become essential. Such apprenticeships have become relatively rare, however, as a growing number of machinists and tool programmers receive most of their formal training from community or technical colleges.
Qualifications for tool programmers vary widely depending upon the complexity of the job. Basic requirements parallel those of machinists. Employers often prefer skilled machinists, tool and die makers, or those with technical school training. For some specialized types of programming, such as with complex parts for the aerospace or shipbuilding industries, employers may prefer individuals with a degree in engineering.
For those entering tool programming directly, a basic knowledge of computers and electronics is necessary and experience with machine tools is extremely helpful. Classroom training includes an introduction to numerical control and the basics of programming and then advances to more complex topics such as computer-aided manufacturing. Trainees start writing simple programs under the direction of an experienced programmer. Although machinery manufacturers are trying to standardize programming languages, there are numerous languages in use. Because of this, tool programmers should be able to learn new programming languages.
As new automation is introduced, machinists and tool programmers generally receive additional training to update their skills. This training is usually provided by a representative of the equipment manufacturer or a local technical school. Some employers offer tuition reimbursement for job-related courses.
ADVANCEMENT Workers may advance in several ways. Experienced machinists may become tool programmers; some move into supervisory or administrative positions in their firms; and a few may open their own shops.
Earnings of machinists compare favorably with those of other skilled workers. In 1996, median weekly earnings for machinists were about $550. Most earned between $410 and $700. The lowest paid 10 percent of all machinists had median weekly earnings of less than $310; the 10 percent with the highest earnings made more than $870 a week.
Machinists and tool programmers held about 393,000 jobs in 1996. Most machinists worked in small machining shops or in manufacturing firms that produce durable goods, such as metalworking and industrial machinery, aircraft or motor vehicles. Maintenance machinists work in most industries that use production machinery. Although machinists and tool programmers work in all parts of the country, jobs are most plentiful in areas where manufacturing is concentrated.
Employment of machinists and tool programmers is expected to decline slightly through the year 2006. Despite this decline, job opportunities will be good for machinists, as employers continue to report difficulties in finding workers with the necessary skills and knowledge to fill machining and tool programming openings. Many job openings will arise each year from the need to replace experienced machinists and programmers who transfer to other occupations or retire. The number of openings for machinists is expected to be far greater than the number of openings for tool programmers, primarily because the occupation is larger.
Automation is contributing to the slight employment decline projected for machinists and tool programmers. The use of computer-controlled machine tools, for example, reduces the time required for machining operations and increases worker productivity. This allows fewer machinists to accomplish the same amount of work previously performed by more workers. The impact of CNC technology on the employment of machinists is limited, however, because many of the unique operations performed by these workers cannot be efficiently automated, and because firms are likely to retain their most skilled workers to operate expensive new machinery.
Although employment of tool programmers was initially made possible by the introduction of new automation in firms, recent technological advancements are reducing demand for these workers. For example, advanced machine tool technology allows some programming and minor adjustments to be performed on the shop floor by machinists, tool and die makers, and machine operators. In addition, fewer programmers will be needed to translate part and product designs into CNC machine tool instructions due to the increasing use of software that automatically performs this function.
Employment levels in these occupations is also influenced by economic cycles; as the demand for machined goods falls, machinists and tool programmers involved in production may be laid off or forced to work fewer hours. Employment of machinists involved in plant maintenance, however, is often more stable because proper maintenance and repair of costly equipment remain vital concerns even when production levels fall.