Basics of CNC Programming

Do you speak fluent G-code?

If that sentence doesn't make sense to you, keep reading and it will by the end of this article. Let's dive right in!

CNC machines are an essential part of modern-day manufacturing. They allow for highly precise and efficient production of parts and components. They are also fast and cost efficient. Whether you are new to the field of manufacturing or just looking to get some questions answered, read on for a basic overview of CNC machines and programming.

CNC, also known as Computer Numerical Control Programming, is a process of creating a set of instructions that tell a CNC machine how to move its tools and perform specific operations such as cutting, drilling, and shaping materials.  CNC uses a subtractive manufacturing process to cut away portions of the base material to shape the desired form. These machines are used in various industries such as manufacturing, to produce the high precision parts and components. To sum it up, you enter 3D files into a computer which then runs a specific program that controls the tools inside the machine.

History of CNC Machines

Who doesn’t love a good history lesson? Although turning machines were made before this time, the first CNC machine was credited to James Parsons in 1949. Parsons was a computer pioneer who worked on Air Force Research Project. The research was on how to produce helicopter blades and better aircraft skin. Parsons was able to calculate helicopter airfoil coordinates with an IBM 602A multiplier. He then fed data into a punched card, which he used on a Swiss jig borer.

Although the CNC machines were around in the 1950’s, the use of computerized controls for these machines didn’t become widespread until the 1970’s. Fascinating, isn’t it?



The machines use a language to follow a set of instructions, and the most common is called G-Code, (there are other languages like IAO,  Mazatrol, and Heidenhain but we won’t discuss those here.) which contains a series of commands that are interpreted by the machine’s controller. The G-code contains commands that tell the machine how to move its tools and where to cut, drill, or shape the material being worked on. We have a couple CNC machines right here in our shop at Machine Ethics!

CNC programming can be done manually, using a text editor or specialized software, or it can be generated automatically by Computer-aided manufacturing (CAM) software that converts a 3D model into G-code. CNC Programming requires a good understanding of mathematics, as well as knowledge of Computer-aided design (CAD) software and the CNC machine’s capabilities, The programmer must also have a thorough understanding of the material being worked on and the specific cutting being used.


Types of CNC Machines

There are several types of CNC Machines o I am going to highlight the ones that are more commonly used.


CNC Mills

CNC Mills manufactures high quality parts to a very high-level detail. They are designed for mass production and are used for cutting and shaping a variety of materials, including metal, wood, and plastics. CNC Mills use a rotating cutting tool to remove material from a work piece. Using a CNC Mill reduces the labor during the production process significantly.

CNC Lathes

CNC Lathes are used for turning and shaping cylindrical parts. They use a rotating work piece and a cutting tool that moves along the length of the workpiece . Check out the video below to see a Romi CNC Lathe that we here at Machine Ethics are authorized to sell!

 CNC Plasma Cutters

CNC Plasma Cutters are used for cutting metal using a high-velocity jet of ironized gas along a multi-axis grid. They are often used in industrial applications for cutting thick metal parts. The great thing about a CNC Plasma Cutter over a manual is that the CNC machine is in control whereas a manual is being controlled by human motion.

CNC Waterjet Cutters

CNC Waterjet Cutters are used for cutting a wide range of materials, including metal, stone, glass, and composites. They use a high-pressure jet of water mixed abrasive particles to cut through the material.

CNC Routers

CNC Routers are used for cutting and shaping wood, plastics, and other materials. They use a spinning cutting tool to remove material from a workpiece, and can be used for 2D and 3D cutting. There are 3 Axis routers and 5 Axis Routers. There is a lot more that goes into this, but to keep it simple, the difference between the two is that 3-axis and the 5-axis can be worked on from3 axes or 5 axes. There are pros and cons to both (your budget, complexity of your project, just to name a few).

CNC Laser Cutters

CNC Laser Cutters are used for cutting and engraving a variety of materials, including metal, wood and plastics. They use a high-energy laser beam to cut through the material.

Grinding CNC Machine

A grinding CNC machine uses a rotating wheel to cut metal away from the metal. CNC Grinding machines need an accurate finish and are often used for ball bearings and transmission shafts.


Every machine is different, but here are the most basic steps in the CNC programming process!

 1.   Define the part geometry. The first step is to define the part’s geometry by creating a 2D or 3D CAD model using CAD software. The CAD model includes such information as the part’s dimensions, shape and features.

2.   Create a toolpath: Once the CAD model is complete, the next step is to create a toolpath. A toolpath is a set of instructions that tell the CNC machine how to move the cutting tool to remove material from the workpiece. Toolpaths are created using computer-aided manufacturing software, (CAM) which generates toolpath data based on the CAD model.

3.   Select cutting tools: The next step is to select the cutting tools that will be used to remove material from the workpiece. The cutting tools must be chose based on the material being machined, the geometry of the part, and the desired surface finish.

4.   Define cutting parameters: Cutting parameters such as spindle speed, feed rate, and depth of cut must be defined based on the material being machined and the cutting tools being used.

5.   Write the CNC program: The Final step is to write the CNC program. The program consists of a set of instructions that tell the CNC machine how to move the cutting tool along the toolpath and how to adjust the cutting parameters as needed.

6.   Test and Refine the Program: Before running the program on the CNC machine, its important to test and refine the program to ensure that it produces the desired results. This may involve adjusting the cutting parameters, tool selection, or toolpath. Once the program has been refined, it can be loaded onto the CNC machine and run to manufacture the part.



 This article explained what CNC Machines are, the history of CNC Machines, the language of them, and the different types. To learn more, head over to our website. What machine sounds like the best to start with for your project or line or work?


Machine Ethics is an established, certified repair company that can repair or program your CNC, or any machine with any issue. We have you covered for your maintenance needs whether its locally, regionally and even globally. We are also certified to sell the machines in the video's above as well as many others and would love to be able to help you find what you are looking for! Get in touch to discuss your project needs!

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