CNC definition and CNC machine working

Definition of CNC Technology

CNC technology has been around for a while – since the 1950s – but has become increasingly more precise over the past few decades thanks to the sophistication of modern computers. If you’re familiar with the manufacturing world at all, you’ve probably heard of CNC – Computer Numerical Control. CNC is a way of controlling how machine tools operate using a computer. CNC is a process and technique for controlling high-end machinery to produce parts according to a specific plan.

CNC typically applies to subtraction methods of machining, such as milling, grinding, and lathe work. These methods take an existing piece of metal and remove the material bit by bit, until the desired part takes shape. Machining work takes place in a variety of industries, from automobile parts production to heavy industry. Anywhere there are complicated machines at work, there’s probably a dedicated machine shop or even an entire factory devoted to repairing, manufacturing, and supporting those machines – and many of those parts will be produced on CNC machines.

CNC Machining Process overview

CNC machining is a manufacturing process which utilizes computerized controls to operate and manipulate machine and cutting tools to shape the material into custom parts and designs.

The basic CNC machining process includes the following stages:

  • Designing the CAD model

The first stage is drawing 2D or 3D model of machine component along with the necessary technical specifications, such as dimensions and geometries, for producing the part or product. Once the CAD design is completed, the designer exports it to a CNC-compatible file format, such as STEP or IGES.

  • Converting the CAD file to a CNC program

CNC machines used several programming languages, including G-code (General or Geometric code) and M-code (Miscellaneous function code)

G-code, controls when, where, and how the machine tools move. M-code, controls the auxiliary functions of the machine, such as automating the removal and replacement of the machine cover at the start and end of production, respectively

  • Preparing the CNC machine

Preparing the CNC machine include affixing the workpiece directly into the machine and attaching the required tooling

  • Executing the machining operation

The CNC program acts as instructions for the CNC machine.

How do CNC machines work?

Computer Numerical Control originally used a series of mechanical punch cards, which told the machine where to move next to perform an operation. The recent explosion of CNC machines can be linked to the use of computers with CNC machines. Today’s machines allow an operator to input a program using a special language known as G-code. Once a program is entered into the machine, it can be run continuously and repeatedly. If you’ve got the program to make a certain part, you can make hundreds or thousands of the parts without ever needing to change the program.

G-code languages vary slightly from machine to machine, or more accurately from manufacturer to manufacturer. But over time, many programs have become standardized. Programs for basic machining operations, like cutting threads on a screw, are frequently found as canned programs, requiring only basic modification to run a new operation. These shortcuts help to cut down on the single biggest downside to a CNC machine: the need to write a new program for any new operation.

What are the advantages of CNC parts?

What’s the advantage of CNC parts? First, CNC parts can be made identical. A program designed to make Part A will make as many Part A’s as the operator tells it to, and barring an unforeseen error, each part will be made exactly the same. Consistency across an entire production run of parts means better quality control and less waste. While it’s true that a new part requires a new program, after the program has been created, a CNC machine can execute it with little-to-no required intervention by the human operator.

Because CNC parts are essentially computer-controlled, they can be made complex. Parts that would be nearly impossible to make by hand can be cut, with a very high degree of precision, by CNC-equipped machines. The application of CNC techniques to subtraction methods of machining has opened up new realms of possibilities in manufacturing. New manufacturing methods, like 3D printing, apply CNC technology to additional methods of machining. CNC methods are already the manufacturing standards; 3D printing and similar methods will only reinforce that dominance moving forward.

CNC technology transformed the machining process, also transforming what’s possible with CNC parts. With computer-controlled machines, parts can be made with multiple tools and different processes – milling, turning, etc. – All on the same machine in a single program. The end result is technically advanced parts produced more quickly and more efficiently than ever. The recent advances in CNC parts and technology don’t seem likely to stop anytime soon; the incorporation of additive machining processes like 3D printing promise to increase the variety of parts which can be produced using CNC.


These are the basics of the CNC  technology with CNC defination and CNC machines working. Although CNC machines have advantages over other manufacturing processes, it may not be appropriate for every manufacturing application, and other processes (mechanical, chemical, electro-chemical) may prove more suitable and cost-effective. So manufacturer should choose the most optimal method.

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