Machinists produce precision metal parts, usually using machine tools such as lathes, drill presses, and milling machines. Although machinists can and sometimes do produce large quantities of one part, machinists often produce small batches or one-of-a-kind items. They set up and operate a wide variety of machine tools and know the working properties of metals such as steel, cast iron, aluminum, and brass. Using their skill with machine tools and their knowledge of metals, machinists plan and carry out the operations needed to make machined products that meet precise specifications.
Increasingly, the machine tools used to produce metal parts are numerically controlled (NC) that is, they contain an electronic controller that directs the machine's operations. Most NC machines today are computer numerically controlled (CNC), which means that the controllers are computers. 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 quality of the products these machines produce depends largely on the programs, which may be produced by machinists or by workers who specialize in programming machine tools known as tool programmers. Although tool programmers and machinists are often considered separate occupations, because many of their duties are very similar or identical, both are covered in this statement.
Machinists 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, they perform the necessary machining operations. Machinists position the metal stock on the machine tool drill presses, lathes, milling machines, or others set the controls, and make the cuts. Today, new machinery allows various functions to be performed with one setup, which reduces the need for additional, labor-intensive setups, saving time and money. During the machining process, they must constantly monitor the feed and speed of the machine. Machinists must also ensure that the workpiece is being properly lubricated and cooled because the machining of metal products generates a significant amount of heat.
Traditionally, machinists have had direct control of their machines. However, the introduction of numerically controlled machines, and in particular, computer numerically controlled machines, has greatly changed the Nature of the Work for machinists. NC machines not only are more productive, they enable parts to be produced with a level of precision beyond that 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. This uniformity is key to fulfilling customers' needs for quality products.
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 also do programming. As computer software becomes more user friendly, machinists are expected to perform this function increasingly.
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. Programs can then be used for other jobs with similar specifications by making small adjustments to the existing program. This reduces the time and effort needed to start production of a part.
A growing number of firms have computer-aided design (CAD) systems that are used to write programs. When a part is designed using a CAD system, data about its dimensions are calculated; the CAD system can then use these data to develop the controller's program.
As machinery has become more complex, close tolerances or high precision of machined parts has also increased in importance. In some cases, for example, a part may have to meet specifications equal to one-twentieth of a strand of hair. As a result measuring devices have also increased in sophistication. Optical, acoustical, and laser measuring devices commonly ensure that work meets specifications.
Although machinists and tool programmers perform many similar duties, jobs can vary greatly. Some machinists, often called production machinists, may produce large quantities of one part, especially parts needing unusually complex operations, great precision, or when unusually sophisticated, expensive machinery is used. Usually, however, large numbers of parts requiring more routine operations are produced by metalworking machine operators (see the statement on metalworking and plastics-working machine operators elsewhere in the Handbook). Other machinists do maintenance work repairing or making new parts for existing machinery. For example, 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.
Machinists frequently use lathes to make round or circular parts.
Most machine shops are well lighted 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 cleaning and disposing of coolants and lubricants because many of these materials can be hazardous. 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 lighted, 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 invest in more expensive machinery. Overtime is common during peak production periods.
Machinists and tool programmers held about 359,000 jobs in 1992. 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.
A high school or vocational school education, including mathematics, blueprint reading, metalworking, and drafting, is desirable 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 helpful. In fact, many of the people who enter the occupation have previously worked as machine tool operators or setters.
Machinist training varies from formal apprenticeship programs to informal on-the-job training. However, most employers consider a formal apprenticeship program the best way to learn the machinist trade. 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 numerically controlled machine tools has become essential. Community colleges and technical institutes increasingly offer classroom training in connection with company or association training programs.
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 helpful because of the increased use of computer-controlled machine tools. Experience with machine tools also is 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 design. Then, trainees start writing simple programs under the direction of an experienced programmer. Although machinery manufacturers are trying to standardize programming languages, currently there are numerous languages in use. Because of this, tool programmers must be able to learn and adapt to new programming languages.
Established workers may also take courses to update their skills and to learn the latest technology and equipment. Some employers offer tuition reimbursement for job-related courses. In addition, when new machinery is introduced, workers receive training in its operation usually from a representative of the equipment manufacturer.
Persons interested in becoming a machinist or tool programmer should be mechanically inclined. They also should be able to work independently and do highly accurate work that requires concentration as well as physical effort.
Employment of machinists and tool programmers is expected to decline slightly through the year 2005. Nevertheless, many job openings will arise each year from the need to replace experienced machinists and programmers who transfer to other occupations or retire. In recent years, employers have reported difficulties in attracting workers to machining and tool programming occupations. Therefore, good employment opportunities should exist for candidates with the necessary mechanical and mathematical aptitudes.
The number of openings for machinists is expected to be far greater than the number of openings for tool programmers because there are many more machinists than tool programmers. In addition, machinists are increasingly taking on the functions of tool programming as the programming of machine tools becomes easier due to simplified programming languages and procedures.
As the economy expands, so will the demand for goods that use machined metal parts. But, demand for these workers will be constrained by improvements in metalworking technology. For example, the use of computer-controlled machine tools reduces the time required for machining operations and increases productivity. Furthermore, when demand for machined goods falls, machinists and tool programmers involved in production may be laid off or be forced to work fewer hours. Apprenticeship opportunities may also decline.
Employment of machinists involved in plant maintenance is often more stable because proper maintenance and repair of costly equipment remain vital concerns even when production levels fall.
Earnings of machinists compare favorably with those of other skilled workers. In 1992, median weekly earnings for machinists were about $492. Most earned between $376 and $623. Ten percent of all machinists had median weekly earnings of less than $275; the 10 percent with the highest earnings made more than $750 a week. In addition to their hourly wage, most workers receive health and life insurance, a pension plan, paid vacations, and sick leave.
Occupations most closely related to that of machinist and tool programmer are, of course, the other machining occupations. These include tool and die maker, tool and die designer, tool planner, and instrument maker. Workers in other occupations that require precision and skill in working with metal include blacksmiths, gunsmiths, locksmiths, metal patternmakers, and welders.
Tool programmers apply their knowledge of machining operations, metals, blueprints, and machine programming to write programs that run machine tools. Computer programmers also write detailed instructions for a machine in this case a computer.
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Reprinted with Permission of U. S. Department of Labor