What is Cnc Programming

The most basic function of a CNC (Computer Numerical Control) program is to enable a machine to automate precise and consistent motion control.  Doing this requires programming instructions, written in a computer language code, that talks to the machine and tells it how to run a part. Each unique part requires its own CNC program.

What is Cnc lathe programming?

Cnc lathe programming means write CNC programming code on a Lathe or Turning Machine. To make the lathe remove a layer of material per CNC instruction.

CNC is deeply involved in the manufacturing process and has greatly improved automation along with flexibility. It has been around since the early 1970’s and is often referred to as NC programming. CNC has touched almost every form of the manufacturing process.

Benefits of Cnc programming

It is no longer necessary for the operator to stand in front of the machine while operating controls because the operator no longer controls the machine tool movements. This has created better efficiencies. Conventional machine tools only spent about 20 percent of the time removing material. With CNC programming, actual time spent removing materials has increased to 80 percent or higher. Plus, it has reduced the time required to bring the cutting tool into each position.

Some other benefits of Cnc programming was used on CNC machine include:

1. Improved automation

2. Consistent and accurate work pieces

3. Reliable and flexible processes

4. Takes less time to perform each job

5. Requires less operators

6. No possibility of human error

7. Safe to operate

8. Low maintenance

9. Versatile

10. Uniformity

11. Can run 24/7

There are many applications of CNC machines, including metal removal industries, material fabrication industries, and for non-conventional machining industries where the machining task is difficult to perform manually.

CNC Program Code

CNC programming is used by manufacturers all around the world. To run this automated process requires a set of instructions that tells the CNC machine where, and how, to move. The most widely used computer numerical control programming language is known as G-Code. It is an extremely compact and concise language that might seem very outdated at first glance.  It is mainly used for CNC machines.

The Electronics Industry Association (EIA) first established G-code in the 1960’s. Officially it was documented as RS-274D, but it is now referred to as G-code because many of the pieces of code that make up the language start with the letter G. It has also been said that the G stands for geometry.

G-code tells the parts where to start, how to move and when to stop. For example, a G-code tells the machine tool what type of action to perform, such as “rapid movement,” or “transport the tool as quickly as possible in between cuts.”

A program contains a definition statement, a machining statement, and a closing statement.

The definition statement has a program number, defining the origin, etc. The machining statement defines the movements of the tool. Some examples are shown below, such as command G01, that tells the machine to perform a linear feed move. The closing statements tell the machine that the program ended.  It then moves back to the original position, stops the coolant, etc. Closing statements are the same for most programs.

You can see an example arrangement of a block later in this article.

Here is an example of G-code block that shows its simplicity:

G01 X1 Y1 F20 T01 M03 S500

This is a series of instructions for the machine to perform.

· G01 – Perform a linear feed move

· X1/Y1 – Move to these X and Y coordinates

· F20 – Move at a feed rate of 20

· T01 – Use Tool 1 to get the job done

· M03 – Turn the spindle on

· S500 – Set a spindle speed of 500

A complete CNC program will have multiple lines of G-code like these. The CNC machine processes the code one line at a time. It reads left to right, top to bottom, just like you are reading this article. Each set of instruction is on its own line, known as a block.

Considerations for Writing a CNC Program

The first goal of every G-code program is to design for safety and efficiency. CNC programmers determine the sequence of actions that it takes to make a part, after evaluating the specifications for that particular part. Calculations are made based on the raw materials being used and physical production. This includes the kind of material that will be used (metals, plastics), how fast it should be fed into the machine, where fabrications are located on the piece, and other requirements. These specs are then turned into the series of numbered, sequential instructions as shown in the example above. These instructions are then downloaded onto the machine.

Before the program is used by a machine operator, a CNC set-up operator downloads the program onto the machine to test it and make any needed modifications or improvements.

G-code blocks must be arranged in a precise order to run safely and efficiently, as shown here:

Start the CNC program written for this project

·      1. Load the required tool

·      2. Turn the spindle on

·      3. Turn the coolant on

·      4. Move to position above a part

·      5. Start the machining process

·      6. Turn the coolant off

·      7. Turn the spindle off

·      8. Move away from the part to a safe location

·      9. End the CNC program

Three Programming Styles

There are three kinds of programming instruction styles to choose from: manual, conversational, and CAM.

Manual is done without a computer and involves many calculations and verifications. Even though it is considered old school, it is still viable in part machining. CNC programming can be considered an art form and can never really be fully automated. Manual programming gives full control over the program and allows the programmer to use basic instincts.

Conversational programming is great for the entry level operator. Part programs can easily be generated at the machine in minutes. However, it is best for simple part geometries which means those that take 30 minutes or less to program.

CAM system automatically generates G-code language responsible for controlling the CNC machine. It is essential to have this system if you do not have highly skilled machinist in the shop. CAM does not require operators to perform math calculations and automates the programming process. However, efficient programming management still requires some basic programming knowledge. It is also less efficient than manual methods.

Cnc Programmer salary

Manufacturers all around the world use CNC programming so learning this skill can be a valuable career choice. The average salary in the US for a CNC programmer is $54,000 per year compared to CNC operators and CNC machinists who average $42,000.  Learning the programming might be easy, but mastering it takes more time. A few months of on the job training may be enough but a year or more is needed to become highly skilled and be an asset to a machine shop.

CNC programming can be learned through online courses, but the best option is to learn as an intern at a machine shop.

Manufacturers around the world use CNC machines and require programmers with the skill to write the code that makes them work.