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Two Major Types of Codes Used to Run CNC Machinery

The acronym ‘CNC’ stands for Computer Numerical Control, and it refers to the machines controlled by numerical codes generated through computerized programming languages. All the CNC machinery for sale in the market runs through these codes, and these numbers ensure that every function of this equipment is flawless, precise, and quick. There are two primary types, the G-code and M-code. They’re created through almost the same process but have slightly different roles when making the machines work. This article will discuss those two types, the functions they perform, and how they’re differentiated. We suggest you read until the end to learn something valuable about the codes before you decide about purchasing one.

If you wish to buy the machines from a reliable and trustworthy vendor, we suggest you visit Flint Machine Tools as they provide you with fully functional and durable equipment.

The Primary Types of Codes Used in CNC Machinery for Sale


The G-code is the most popular code used to run CNC mills and lathes. It was designed in the early days of CNC technology and is still being used extensively because of its reliability and simplicity. It consists of simple lines and curves to be executed in order. The G-code makes the cutters and blades function in specific manners, like moving to a particular point on the machine and turning the head at a specific angle.
Many manufacturers even use G-codes for programming two or more consecutive operations to reduce the machining time of a complex component. A notable feature of G-code is that it can be used to operate different types of machines available at any CNC tool distributor in Georgia, North Carolina, South Carolina, Tennessee, Alabama and the Southeast, making it a versatile code.


The M-code was specifically designed for CNC routers and mills. It contains all the necessary information about the workpiece, including its dimensions, shape, and location on the machine. It consists of two major subtypes, the milling codes and router codes. High-end machines usually use these codes to operate since it provides more precise data about the machining job at hand.
The milling code uses a non-linear approach for programming combined operations like drilling, routing, and contouring. It employs a look-ahead feature to calculate the tool paths in advance and avoid collisions. This code is perfect for complex components with intricate shapes.
Conversely, the router code uses a linear programming technique that’s simpler but less accurate. It’s best suited for regular parts with simple shapes that don’t require a high degree of accuracy.

Differences in G-code and M-code

As mentioned earlier, both the codes operate on different machines. The G-code is used to run CNC mills that cut, shape, drill, or bore components through rotary axes, while the M-codes are for routers that make straight cuts. Some of the basic differences between these two codes are listed below.

  • G-code is easy to learn and use, whereas M-code requires some expertise for efficient implementation.
  • The G-code must be set on the machine manually every time you wish to use it, while the M-codes can be permanently set on the machine.
  • M-codes are more precise and give you more control over the process, while G-codes are easy to use.
  • G-code programs can be used to run multiple processes, whereas M-codes are only applied to cutter machines that ‘mill’ or ‘route’ materials.

Many manufacturing companies using CNC machinery use both the codes for designing and programming processes. They’re also used in conjunction with other codes like the M2. These combinations make it possible to design sophisticated machines that easily turn materials into useful components.

We have described the two primary codes used by CNC equipment and hope that the information is enough to help you understand them. If you still have any queries about the working of these machines or wish to buy them, we suggest you contact Flint Machines Tools, as they may have the most reliable and durable equipment you need.

We have also discussed some of the most frequently and commonly asked questions about the topic below. Kindly read them as well to get some additional information.


What type of coding does a CNC machine use?

A CNC machinery for sale uses two types of coding: G-code and M-code. G-code is used to run CNC mills, while M-codes are for routers. Both types of coding are necessary to program a CNC machine for different processes.

What is CNC programming?

CNC programming is writing G-code or M-code on CNC machinery for sale. These codes are written in different languages but can be converted to one another easily. CNC programs are used to program the movement of components and guide them through complex machining processes like drilling and shaping.

Do all CNC machines use G code?

No, only the milling CNC machinery uses G-code. CNC routers use M-code instead. G-code is easy to learn and implement, whereas M-codes require efficient implementation.

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