What is CNC Router Programming?

CNC Programming Tips

Computer Numerical Control (CNC) routers are crucial in every industrial machining operation today. Thanks to their accuracy and precision, workshops can achieve higher production speeds while maintaining product quality, whether for mass-producing goods or creating unique, masterfully crafted pieces.


CNC router programming makes all of the router’s functionalities possible, enabling the machine to perform its various functions through loaded instructions. Through this programming, the machine can perform various tasks to produce the intended part.


One popular way to program CNC routers is using computer-aided manufacturing (CAM) software packages. However, it isn’t the only way to program the machine. Below, we delve into the different types of CNC programming and how these are performed to help you execute the desired machining process.


What Is CNC Router Programming?

CNC programming refers to developing code that instructs the CNC router to execute the task required in a manufacturing process. Essentially, this code is what is used to convert instructions, in the form of a three-dimensional computer-aided design (3D CAD) model, into executable instructions for the machine: what cutting tools to use, how the cut is to be performed, the feed rate of the material and how the tool will move to replicate the design.


How Does CNC Programming Work?

Codes are programmed by the programmer instructing the machine to perform several tasks to create the product. Depending on the type of programming used, the programmer will have to manually create and input the codes on the machine’s console or use modeling software to streamline the process. The simplest of these types is through CAD modeling and CAM software.


In CAD modeling, 3D CAD models contain all the information about the desired product, namely its size, profile and three-dimensional conformation. When fed into CNC programming, the machine’s software translates all this information into workable instructions.


Before the router can perform any actions required to cut the material and produce the desired product, the programmer must program various tool paths within the CAM software according to the product’s geometry. These tool paths include actions that produce slots, holes, contours or any other surface configuration.


Once all of these tool paths have been set, the software will generate the set of commands, often called G-Codes. The G-codes are then given to the machine, which it will then execute to begin the production cycle. This will all be completed after the instructions have been performed to produce the final product.


What Codes Are Used for CNC Programming?

A program is a sequence of codes that tells the CNC router what to do. These programmed codes allow the machine to perform the correct action for greater accuracy while making those actions more precise to make the production process more repeatable.


A programmer uses different codes to set these functions. These programming codes are task-specific and are identified by different alphabet letters. These codes are collectively known as G-Codes, as mentioned above, and encompass all the types of coded instructions required to carry out production successfully. 


However, the term “G” also refers explicitly to codes that alter the material’s geometry. The G-Code, along with other code types, is described in more detail below (in alphabetical order):


  • D-Codes refer to the offset tool and can provide instruction about the placement of the tool with regards to the position of the tool’s center line from its cutting edge, or how far the tool holder sticks out from this line.
  • F-Codes are feed rate codes. They control how fast the tool moves while cutting through the material.
  • G-Codes are “geometrical” codes that control how the tool moves relative to the product’s geometry. This provides instructions regarding where it should move from a designated position and what actions to perform as it moves between these points. 
  • M-Codes control various functions (non-geometric functions), such as spindle control and how much coolant to use.
  • N-Codes are used to differentiate between lines or blocks of code. Although these line numbers aren’t required for CAM-generated code, they can help the programmer organize and follow manually-written code.
  • S-Codes, also known as speed codes, are used to control how fast the spindle turns while moving through the material.
  • T-Codes are tool codes that provide instructions about what tool to use while building a specific feature on the workpiece. 


In coding, the letter codes are followed by a number, which identifies the command. For instance, the geometric command “G00” is a command for rapid movement of the tool, which moves the tool to part geometry at the maximum rate. 


Types of CNC Programming

Coded instructions are typically written in a straightforward, logical manner as a series of steps the router follows. It reads one letter code at a time and executes the command given before moving on to the next step.


Programmers can create these codes in three ways: manually, through CAM software, or through a conversational approach. Each type of CNC programming is described in more detail below:


Manual CNC Programming

The most basic type of programming is the manual approach, which involves manually inputting commands into a control console attached to the CNC router. In this approach, the programmer lays out all of the instructions and inputs them one by one into the control console to feed the information to the machine.


Manual CNC programming typically requires the most expertise and in-depth knowledge about a CNC machine’s functions. It is usually done for simple parts that require simple instructions to perform. Most experts prefer not to use this method for more complex programming, mainly because it is time-consuming and error-prone.


And unlike other types of programming, manual CNC programming does not have a visualization component nor warnings of possible errors in the code. This is why more expertise and attention to detail are required to create codes perfectly.


Computer-Aided Manufacturing (CAM)

CAM software is one of the most popular types of CNC programming today because it is faster and more accurate than manual programming. While using this method, the software provides a visual representation of the tool paths they want to create, which helps develop correct instructions and spot possible errors in the code that can cause the machine to malfunction. 


CAM software is more flexible and versatile, allowing the user to translate the program from one type of CNC machine to another without any need to rewrite the program. It can also be used to create simple and complex parts while requiring little expertise on the user’s part. 


Typically, the more advanced the CAM software is, the more expensive it will be. But the more advanced the software is, the more freedom it can provide the user to produce more complex components, making it a worthwhile investment for most businesses. 


Conversational Programming

For CNC routers that already contain an interface for conversational programming, the instructions can be provided using plain English and without the need for G-Code. More advanced systems will even look for instructions using a set of questions that the operator answers to define the task.


Although they can simplify the programming task, these systems are usually used for relatively simple operations because of their limited functionalities. However, they still serve as quick alternatives to manual CNC programming.


Industries That Use CNC Routers

Because of the versatility of CNC routers, they have become crucial components in producing components for the following industries:

  • Aerospace
  • Prototyping and 3D Modeling
  • Electronics
  • Furniture Production
  • Military and Defense
  • Medicine and Healthcare


Maximize Your Production Potential With CAMaster


CAMaster is dedicated to meeting the needs of our customers and partners across the globe. With cutting-edge CNC router machines, we can support your need to produce the highest quality products and components and help you gain a competitive edge in your industry. Get in touch with us today to learn more.


CAMaster is committed to meeting the needs of our manufacturing partners across the globe. As the leading supplier of top-quality CNC router machines, we support your operations with superior-quality CNC machines, helping you succeed in your industry. Get in touch with us today to learn more.