Manufacturing industries employ almost all of these workers.
Workers learn in apprenticeship programs, informally on the
job, and in secondary, vocational, or postsecondary schools;
many entrants have previously worked as machinists or machine
setters, operators, and tenders.
Despite the projected decline in employment, job opportunities
should be good, as employers are expected to continue to have
difficulty finding qualified workers.
Nature of the Work
Computer control programmers and operators use computer numerically
controlled (CNC) machines to cut and shape precision products,
such as automobile parts, machine parts, and compressors. CNC
machines include machining tools such as lathes, multiaxis spindles,
milling machines, laser cutting, water jet cutting, and wire electrical
discharge machines (EDM), but the functions formerly performed
by human operators are performed by a computer-control module.
CNC machines cut away material from a solid block of metal, plastic,
or glass—known as a workpiece—to form a finished part. Computer
control programmers and operators normally produce large quantities
of one part, although they may produce small batches or one-of-a-kind
items. They use their knowledge of the working properties of metals
and their skill with CNC programming to design and carry out the
operations needed to make machined products that meet precise
Before CNC programmers—also referred to as numerical tool and
process control programmers—machine a part, they must carefully
plan and prepare the operation. First, these workers review three-dimensional
computer aided/automated design (CAD) blueprints of the part.
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 and
plan the sequence of cutting and finishing operations.
Next, CNC programmers turn the planned machining operations into
a set of instructions. These instructions are translated into
a computer aided/automated manufacturing (CAM) program containing
a set of commands for the machine to follow. These commands normally
are a series of numbers (hence, numerical control) that describes
where cuts should occur, what type of cut should be used, and
the speed of the cut. CNC programmers and operators check new
programs to ensure that the machinery will function properly and
that the output will meet specifications. Because a problem with
the program could damage costly machinery and cutting tools or
simply waste valuable time and materials, computer simulations
may be used to check the program instead of a trial run. If errors
are found, the program must be changed and retested until the
problem is resolved. In addition, growing connectivity between
CAD/CAM software and CNC machine tools is raising productivity
by automatically translating designs into instructions for the
computer controller on the machine tool. These new CAM technologies
enable programs to be easily modified for use on other jobs with
After the programming work is completed, CNC operators—also referred
to as computer-controlled machine tool operators, metal and plastic—perform
the necessary machining operations. The CNC operators transfer
the commands from the server to the CNC control module using a
computer network link or floppy disk. Many advanced control modules
are conversational, meaning that they ask the operator a series
of questions about the nature of the task. CNC operators position
the metal stock on the CNC machine tool—spindle, lathe, milling
machine, or other—set the controls, and let the computer make
the cuts. Heavier objects may be loaded with the assistance of
other workers, autoloaders, a crane, or a forklift. During the
machining process, computer-control operators constantly check
to see if any problems exist. Machine tools have unique characteristics,
which can be problematic. During a machining operation, the operator
modifies the cutting program to account for any problems encountered.
Operators who make these adjustments need a basic knowledge of
CNC programming. Unique, modified CNC programs are saved for every
different machine that performs a task.
In order to boost productivity, manufacturers increasing prefer
workers who can quickly adapt to new technology and perform a
wide range of tasks. As a result, CNC operators often are required
to perform many of the basic skills of a machinist and a CNC programmer.
However, some manufacturers simply need CNC operators to be “button-pushers.”
They primarily start and stop machines, load cutting programs,
and load and unload parts and tools.
Regardless of skill level, all CNC operators detect some problems
by listening for specific sounds—for example, a dull cutting tool
that needs changing or excessive vibration. Machine tools rotate
at high speeds, which can create problems with harmonic vibrations
in the workpiece. Vibrations cause the machine tools to make minor
cutting errors, hurting the quality of the product. Operators
listen for vibrations and then adjust the cutting speed to compensate.
In older, slower machine tools, the cutting speed would be reduced
to eliminate the vibrations, but the amount of time needed to
finish the product would increase as a result. In newer, high-speed
CNC machines, increasing the cutting speed normally eliminates
the vibrations and reduces production time. CNC operators also
ensure that the workpiece is being properly lubricated and cooled,
because the machining of metal products generates a significant
amount of heat.
Since CNC machines can operate with limited input from the operator,
a single operator may monitor several machines simultaneously.
Typically, an operator might monitor two machines cutting relatively
simple parts cut from softer materials, while devoting most of
his or her attention to a third machine cutting a much more difficult
part cut from a hard metal, such as stainless steel. Operators
are often expected to carefully schedule their work so that all
of the machines are always operating.
Most machine shops are clean, well lit, and ventilated. Most
modern CNC machines are partially or totally enclosed, minimizing
the exposure of workers to noise, debris, and the lubricants used
to cool workpieces during machining. Nevertheless, working around
machine tools presents certain dangers, and workers must follow
safety precautions. Computer-controlled machine tool operators,
metal and plastic, wear protective equipment, such as safety glasses
to shield against bits of flying metal and earplugs to dampen
machinery noise. They also must exercise caution when handling
hazardous coolants and lubricants. The job requires stamina because
operators stand most of the day and, at times, may need to lift
moderately heavy workpieces.
Numerical tool and process control programmers work on desktop
computers in offices that typically are near, but separate from,
the shop floor. These work areas usually are clean, well lit,
and free of machine noise. Numerical tool and process control
programmers occasionally need to enter the shop floor to monitor
CNC machining operations. On the shop floor, CNC programmers encounter
the same hazards and exercise the same safety precautions as do
Most computer control programmers and operators work a 40-hour
week. CNC operators increasingly work evening and weekend shifts
as companies justify investments in more expensive machinery by
extending hours of operation. Overtime is common during peak production
Training, Other Qualifications, and Advancement
Computer control programmers and operators train in various ways—in
apprenticeship programs, informally on the job, and in secondary,
vocational, or postsecondary schools. In general, the more skills
needed for the job, the more education and training that is needed
to qualify. For example, a growing number of computer control
programmers and the more skilled operators are receiving their
formal training from community or technical colleges. For some
specialized types of programming, such as that needed to produce
complex parts for the aerospace or shipbuilding industries, employers
may prefer individuals with a degree in engineering.
Less-skilled CNC operators (button-pushers) may need only a couple
of weeks of on-the-job training.
Employers prefer to hire workers who have a basic knowledge of
computers and electronics and experience with machine tools. In
fact, many entrants to these occupations have previously worked
as machinists or machine setters, operators, and tenders. Due
to a shortage of applicants with the appropriate training, many
employers are providing introductory courses in operating metalworking
machines, safety, and blueprint reading. Persons interested in
becoming computer control programmers or operators should be mechanically
inclined and able to work independently and do highly accurate
High school or vocational school courses in mathematics (trigonometry
and algebra), blueprint reading, computer programming, metalworking,
and drafting are recommended. Apprenticeship 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, programming, blueprint reading, CAD software,
safety, and shop practices. Skilled computer control programmers
and operators need an understanding of the machining process,
including the complex physics that occur at the cutting point.
Thus, most training programs teach CNC operators and programmers
to perform operations on manual machines prior to operating CNC
To boost the skill level of all metalworkers and to create a
more uniform standard of competency, a number of training facilities
and colleges have recently begun implementing curriculums incorporating
national skills standards developed by the National Institute
of Metalworking Skills (NIMS). After completing such a curriculum
and passing a performance requirement and written exam, trainees
are granted a NIMS credential that provides formal recognition
of competency in a metalworking field. Completion of a formal
certification program provides expanded career opportunities.
Classroom training includes an introduction to computer numerical
control, the basics of programming, and 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,
computer control programmers and operators should be able to learn
new programming languages.
As new automation is introduced, computer control programmers
and operators normally receive additional training to update their
skills. This training usually is provided by a representative
of the equipment manufacturer or a local technical school. Many
employers offer tuition reimbursement for job-related courses.
Computer control programmers and operators can advance in several
ways. Experienced CNC operators may become CNC programmers, and
some are promoted to supervisory or administrative positions in
their firms. A few open their own shops.
Computer control programmers and operators held about 143,000
jobs in 2004, mostly working in machine shops, plastics products
manufacturing, machinery manufacturing, or transportation equipment
manufacturing making mostly aerospace and automobile parts. Although
computer control programmers and operators work in all parts of
the country, jobs are most plentiful in the areas where manufacturing
Computer control programmers and operators should have good job
opportunities, despite the projected decline in employment. Due
to the limited number of people entering training programs, employers
are expected to continue to have difficulty finding workers with
the necessary skills and knowledge.
Employment of both computer-controlled machine tool operators
and numerical tool and process control programmers is expected
to decline through 2014. While CNC machine tools will be increasingly
used, advances in CNC machine tools and manufacturing technology
will further automate the production process, boosting CNC operator
productivity and limiting employment. The demand for computer
control programmers also will be negatively affected by the increasing
use of software (CAD/CAM) that automatically translates part and
product designs into CNC machine tool instructions.
Employment levels of computer control programmers and operators
are influenced by economic cycles—as the demand for machined goods
falls, programmers and operators involved in production may be
laid off or forced to work fewer hours.
Median hourly earnings of computer-controlled machine tool operators,
metal and plastic, were $14.75 in May 2004. The middle 50 percent
earned between $11.65 and $18.21. The lowest 10 percent earned
less than $9.47, whereas the top 10 percent earned more than $21.67.
Median hourly earnings in the manufacturing industries employing
the largest numbers of computer-controlled machine tool operators,
metal and plastic, in May 2004 were:
Metalworking machinery manufacturing
Other fabricated metal product manufacturing
Machine shops; turned product; and screw,
nut, and bolt manufacturing
Motor vehicle parts manufacturing
Plastics product manufacturing
Median hourly earnings of numerical tool and process control
programmers were $19.31 in May 2004. The middle 50 percent earned
between $15.67 and $24.00. The lowest 10 percent earned less than
$12.89, while the top 10 percent earned more than $28.89.
Occupations most closely related to computer control programmers
and operators are other metal and plastic working occupations,
which include machinists; tool and die makers; machine setters,
operators, and tenders—metal and plastic; and welding, soldering,
and brazing workers. Numerical tool and process control programmers
apply their knowledge of machining operations, metals, blueprints,
and machine programming to write programs that run machine tools.
Computer programmers also write detailed programs to meet precise