What Is Computer Numerical Control (CNC)?

Machine tools don't always need to be operated by hand. Discover the meaning of CNC, or computer numerical control, in this explanatory guide.

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By Entrepreneur Staff

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Humans had to carry out all their machining processes by hand for centuries. Even precision tools had to be maneuvered very carefully, inch by inch, by people holding the devices personally. That all changed with the advent of CNC, or computer numerical control machining.

Read on for more information about the meaning of CNC and how CNC machining works.

Computer numerical control explained

The abbreviation CNC stands for computer numerical control. It refers to automation for the operation, movement and control of machine tools using software embedded in microcomputer chips.

People use CNC for many tools, such as CNC lathes, drills, CNC milling tools and milling machines, grinders, cutting tools and other CNC machine tools, particularly high-speed ones.

With CNC technology, you can install a microchip in a tool, like a saw or a drill, and program instructions into the chip, so the saw or drill does what is necessary automatically and with machine precision.

Related: Is the Future of Manufacturing Automated or Autonomous?

Every object manufactured or modified through CNC processes receives a custom computer program. Computer programs are usually written in specific languages, then stored and executed by machine control units, or MCUs. An MCU is a microcomputer attached to a particular machine. Once programmed, the device follows its instructions strictly.

Before CNC technology, people had to use machine tools by hand. Manufacturing was much slower and less precise.

But thanks to CNC technology, new precision tools have been able to be developed and implemented in various industries ranging from manufacturing to laser printing and 3D printing.

How does CNC work?

When a business or individual makes something with CNC, they usually write a custom computer program for their objective in an international, standard language called "G-code."

Very early in the design or engineering process, a programmer will create a computer-aided design, or CAD, drawing of a part that should be manufactured or adjusted.

The drawing gets translated into G-code, which is then turned into a program and loaded onto an MCU. Remember, each tool has a distinct MCU, although some devices are connected into groups of instruments or larger machines that all operate from the same G-code MCU program.

Once the program is ready, a human CNC operator usually tests the machine or the program without material in place, or they may use a test material or prototype. This allows refinement of the CNC program to iron out any kinks or eliminate bugs.

Once everything is ready, the CNC machine completes its program as directed. It will create an item, cut material or print something with machine precision.

Many CNC systems and technologies integrate with CAD and CAM (computer-aided manufacturing) software. Both types of software can accelerate MCU programming processes, further streamlining manufacturing industries and sectors.

On top of that, CNC systems can integrate with ERP or enterprise resource planning software and similar applications, like enterprise asset management software. Again, this facilitates faster processes, improved plant performance and improved manufacturing results.

Related: This Tech Startup Manufactures Machines For 5-axis Printing

What is computer numerical control machining?

CNC machining uses CNC technology, related programs and related software to manufacture or machine products. For instance, a car manufacturing company doesn't require employees to hand-cut each item or piece for the vehicle.

Instead, CNC machines take programs and designs from software and cut the pieces into suitable shapes and sizes using precise cutting instruments. All that's required is a CNC machinist, making the manufacturing process much cheaper and more straightforward.

We now use CNC machining in most manufacturing industries.

The benefits of CNC machining include the following:

  • Greater cost-effectiveness
  • Greater precision
  • Fewer mistakes, particularly where precise work is involved
  • Faster production because machines don't get tired (and don't make mistakes, as mentioned earlier)
  • Better results for machined parts, objects and products.

Software used for CNC machining

As mentioned above, two primary types of software are most often used for CNC machining and manufacturing.

The first of these is CAD software. CAD software packages are available in many different types, but they are all used to create three-dimensional designs. The most popular CAD programs include AutoCAD, Rhino 3D and SolidWorks.

Related: Why Cambridge-Based Onshape Sees Value In The "Make In India" Initiative

Furthermore, modern, cloud-based CAD software is available for many organizations. Some programs work with CAM software (see below) or integrate with other programs.

Computer-aided manufacturing (CAM) software lets users set up dedicated job trees to organize tool workflows or objectives. They can also set paths for tools and run simulations before allowing a machine to do any real work.

Many CAM programs are add-ons or secondary software to CAD software. They may make G-code programs that tell CNC tools or moving parts where to go or how to orient themselves.

The most popular CAM software programs include Edgecam, Mastercam, HSMWorks, OneCNC and Solidcam. One popular CNC machine manufacturer is HAAS.


CNC is similar to DNC, or distributed numeric control technology, but they differ. Direct numeric controls were created to manage NC programs and manufacturing machine parameters or actions.

Put more simply, DNC technology moves programs over a network from a central server or computer to individual tools' MCUs.

Think of distributed numerical control as CNC, but networked. It coordinates many machines simultaneously and feeds the same program (or a modified version of a core program) to multiple tools simultaneously.

This is how modern manufacturing plants carry out complex operations with many different tools or devices.


CNC machining revolutionized engineering and manufacturing across the board. It's now an important skill you should learn for various job industries.

Check out Entrepreneur's other guides and resources for more information about this topic.

Entrepreneur Staff

Entrepreneur Staff


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