A CNC Programmer utilizing Mastercam to send tool paths to the CNC Milling Machine in order to cut out a part.

What is a CNC Programmer?

Computer Numerical Control Programming is used extensively by manufacturers to develop an instruction with the help of programming for computers to run a machine tool. CNC programming is an integral part of the manufacturing process and it also helps to improve flexibility in the process of manufacturing through automation.

The entire process begins with the programmer evaluating the sequence of machine movements necessary to make a part or a product. The calculations are made by the programmers on the basis of raw materials and the physical process of production. The next step is to develop the series of numbered instructions, arranged in a sequence for the machine to follow and carry out.

The CNC Operator has to download the program or “import the template” into the machine and test it to check whether or not it needs modifications. There programmers also look out for alternations when the machine is all set for the process of manufacturing.

There are many versions of CNC Programming (CAM) languages

There are at least 5 different types of CNC Machines and not all of them can be run through a single set of programming. In fact, there is no single programming language that can be used to feed instructions into different CNC machines. However, the G-programming language or the G-Code is one of the most widely used programming languages.

The G-code is a universal standard in various CNC programming. Although some companies have come up with their unique style of CNC Programming, a chunk of the traditional CNC programming uses the G-code to carry out a command.

There are a variety of different G-code flavors. The task of implementation of these codes comes down to the individual capabilities of each machine. G-coding is done AT the machine as opposed to CAM that can do it remotely from an office of nearby station. For instance, you can input a set of G-codes in a machine to enable or disable coordinate system rotation while you might not need to use the G-code for a machine which comes without the adjustment capability.

The G-code may seem almost like an archaic language at the first glace. It is because the programming language was discovered back in the days when machines had small amounts of memories. The G -code is very easy to understand.

Every code in the program is written in a separate line which is called a Block. These blocks are arranged in a sequence which promotes readability, safety and predictability.

Here is the simplest example of a CNC Program which involves a single tool which is required to perform a single task:

The first input instructs the machine to run the program which is followed by loading the tool. The spindle and the coolant are turned on one after another. Rapid to position above part and machine operations are the next step following which G-codes blocks are included to turn the coolant off, turn the spindle off, move to a safer position and end the CNC Program.

As mentioned earlier, using the G and M code, you can make up most of the contents of the CNC program. For instance, using G28 you shall be able to return to the machine home position while G81 will allow you to run a simple drill cycle.

Similarly, the M codes are used to perform miscellaneous functions like controlling auxiliary options in the machine. You can only include one M code in each block. For instance, M03 is used to turn the spindle clockwise and M04 is used to run the spindle counterclockwise.

CAM is just one type of CNC Software. There are other types as well.

CNC software is a programming software which is used by developers to create codes in order to run a machine controlled by computer.

See below some of the major types of CNC software:

1. CAD Software

Computer Aided Design software is the tool the programmers use to create designs and vectors for their CNC projects. The CAD software is used by developers in various industries including architecture and mechanics. You will find various CAD packages online. Since these packages can cost you an arm and a leg, you need to make a careful choice. Some of the most popular CAD softwares are AutoCAD, SolidWorks, and Rhino3D.

2. CAM Software

The Computer Aided Manufacturing Software is a useful tool for programmers who are not completely familiar with the G&M codes. The software is used to create a G-code for your CAD drawings. With this software you can also create your own G-codes for simple lines and circles. This is popular software among CNC Programmers as it includes the benefit of CAD software and also produces G-codes to run your system. Some of the most popular CAM softwares are One CNC, MeshCAM and MasterCAM.

3. Machine Control Software

Machine Control Software allows you to get your hands on a complete hardware and software solutions that will allow you to build a program and transfer it to the machine. Some of the best CNC control softwares are The Mach series, LinuxCNC, TurboCNC and more.

Different styles of CNC Programming

There are three mainstream programming styles: CAM, Manual and Conversational. Each of these programming styles requires a different input and therefore, no programming style fits the requirements of every company. You must have a good understanding of the fundamentals before you determine a style that best suits your requirements.

3 Major Styles of CNC Programming

1. Manual Programming

Manual Programming is an old school way of preparing a program. The programmer is required to visualize the operations in order to carry out the part program. With the advent of the CAM system, manual programming has almost come to an end. Programmers often use repetitive machining cycles to simplify the manual approach. However, you must develop a program manually if you want to have full command over the part program. It is through programming manually that machines are able to achieve accurate tool paths and

Summing up the matter of the fact, we can tell that manual programming is great for simple tasks while complex programming can be handled by a CAM system.

Listed below are some pros and cons of manual programming.


  • It is best for machine utilization enhancements
  • The outputs are more effective and efficient than most CAM programs
  • It is a great option for ultra high volume work where optimization is required
  • Comes with unlimited when it comes to development of part program


  • It is a time sapping process of programming
  • There is more risk of human errors in manual programming as compared to other system of programming.
  • Less number of programmers are able to program at a level this high.

2. Conversational Programming

This style of programming is best for entry-level programmers who do not possess a great deal of knowledge about G-codes. Through conversational programming, the programmers are able to bypass the usage of G-codes or hide them entirely.

Using conversational programming, it is easy to generate part programs in no time. The programmer can just walk up to the CNC with the art designing and the CNC shall do the needful. The best part about using CNC’s with conversational programming is that it allows you to verify and check the tool path before the production begins.


  • The set up and programming time is reduced
  • Programmers can steer clear of deciphering G-codes
  • One of the simplest CNC programs to use
  • Accounts for a very few programming errors.


  • Conversational CNC programs does not support complex tool paths
  • It is not as flexible as a CAM system

3. CAM System Programming

The CAM programming system is one of the most sought after programming systems as it is capable of generating G-codes easily. The CAM system can be used in situations where there are a multitude of machines to program without changing the programming language. It comes handy when programming certain complex jobs which are tough to program manually.


  • The operators can function without the use of math calculations using CAM System Programming
  • Boosts the total output by automating the process of programming


  • The output is not as efficient as manual programming