What is Computer Numerical Control (CNC)?

Humans had to do all of their machining processes by hand for centuries. Even the precision tools had to be operated very carefully, inch by inch, by people personally holding the devices. Everything changed with the advent of CNC, or Computer Numerical Control Machining.

FOTOGRIN | Shutterstock

Read on for more information on what CNC means and how CNC machining works.

CNC explained

The abbreviation CNC stands for computer numerical control. It refers to the automation of 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, especially high-speed ones.

With CNC technology, you can install a microchip into a tool, such as a saw or drill, and program instructions into the chip, so that the saw or drill does what is needed automatically and with the precision of the machine. .

Related: Is the future of manufacturing automated or autonomous?

Each object made or modified by CNC processes receives a personalized computer program. Computer programs are typically written in specific languages ​​and then stored and executed by machine control units, or MCUs. An MCU is a microcomputer connected to a particular machine. Once programmed, the device strictly follows its instructions.

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 the CNC work?

When a company or individual makes something with CNC, they usually write a custom computer program for their purpose 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 needs to be manufactured or fitted.

The drawing is translated into G code, which is then transformed into a program and loaded onto an MCU. Remember that each tool has a separate MCU, although some devices are connected to clusters of instruments or larger machines that all run from the same G-code MCU program.

Once the program is ready, a human CNC operator typically tests the machine or program without hardware in place, or may use test hardware or a prototype. This allows the CNC program to be fine-tuned to iron out issues or eliminate bugs.

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

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

In addition to this, CNC systems can integrate with ERP or enterprise resource planning software and similar applications, such as enterprise asset management software. Again, this facilitates faster processes, improves plant performance, and improves manufacturing results.

Related: This tech startup manufactures machines for 5-axis printing

What is CNC Machining?

CNC machining uses CNC technology, associated programs and associated software to manufacture or machine products. For example, an automobile manufacturing company does not require employees to hand-cut every item or part for the vehicle.

Instead, CNC machines take programs and designs from software and cut parts into appropriate shapes and sizes using precise cutting instruments. All it takes is a CNC machinist, which makes the manufacturing process much cheaper and simpler.

We now use CNC machining in most manufacturing industries.

The advantages of CNC machining are:

  • Better profitability
  • Greater precision
  • Fewer errors, especially when it comes to precise work
  • Faster production because the machines don’t get tired (and don’t make mistakes, as mentioned before)
  • Better results for machined parts, objects and products.

Software used for CNC machining

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

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

Related: Why Cambridge-based Onshape sees value in the ‘Make In India’ initiative

Additionally, 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 allows users to set up dedicated task trees to organize workflows or tooling purposes. They can also define paths for tools and run simulations before allowing a machine to perform actual work.

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

Popular CAM software includes Edgecam, Mastercam, HSMWorks, OneCNC, and Solidcam. A popular CNC machine manufacturer is HAAS.

CNC versus DNC

CNC is similar to DNC, or Distributed Numerical Control Technology, but they differ. Direct CNCs were created to manage NC programs and manufacturing machine settings or actions.

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

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

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


CNC machining has revolutionized engineering and manufacturing at all levels. This is now an important skill that you should learn for various industries.

Check Other Entrepreneur Guides and Resources for more information on this topic.

Leave a Comment