CNC Programming – Definition, Types, and Tips

Definition of CNC programming

• Computer Numerical Controlled (CNC) machine programming: 
• It is defined as a process in which instructions are combined together to know how this CNC machine moves and functions.
• The CNC machine converts the given raw material into the final product by following the given instructions.
• The beauty of CNC programming is to allow CNC machines to perform repetitive jobs with low material wastage and in a short time.
• CNC programming advantages for fewer operating expenses and high profit that helps businesses to expand.
• CNC programming controls routers, mills, lathes, mill-turn and turn-mill machines, multi-tasking centers, wire EDMs, and industrial robots.
• Generally, instructions to any CNC machine are delivered manually or digitally.
• The manual way includes a human interface into the CNC machine
• The digital method includes offline Computer Aided Manufacturing (CAM) Software.

What are the types of CNC programming methods?

Programming in CNC machines includes three basic methods

Manual CNC Programming

1. In manual CNC programming mode, the programmer or operator enters the code manually.
2. This mode consumes a lot of time to execute a task and this mode is said to be tedious.
3. It requires special programming knowledge however manual programming is a valuable basic skill.
4. Manual mode is an effective way for quick modifications to Computer Numerical Controlled outputs and optimizes code.

Conversational CNC Programming

• It is also known as shop-floor programming.
• This is a popular method of CNC Programming.
• This method involves graphic and menu-driven functions.
• Here, the input commands are directly given to the CNC machine by skilled operators.
• The conversational method reduces potential issues that arise from poor post-processors in CAM

CAM CNC Programming

• Computer Aided Manufacturing (CAM), Computer Numerical Controlled (CNC) programming method is similar to the conversational method.
• CAM CNC system programming method has a lot of advanced features compared to previous manual and conversational programming.
• The computer-aided software in the CAM system provides an advanced GUI with tool path strategies to help the operator to prepare and generate the program and eliminates the requirement of manual programming for direct transfer into the CNC machine.

How to find the right CNC programming type for your needs?

• The basic function of a CNC machine is to enable machine tools to achieve precise control.
• CNC requires detailed programming instructions for proper working and to achieve precise control.
• But as we know there are three methods as discussed above, and each method has both advantages and disadvantages.

Manual programming

• It requires well trained employs
• For instruction execution in a CNC machine, the programming must be composed in the same language

Advantages of manual programming

• Optimizes enhancement of machine utilization and reduces required cycle time.
• The maximum level of CNC machine closeness is achieved.
• Unlimited freedom in a part of program development
• Outputs more efficiently than many CAM systems

Dis-Advantages of manual programming

• Time-consuming
• Increased human error
• Requires CNC programmer
• Worker shortage at this level of programming

Conversational programming

• This method is assigned to entry-level operators or fresher.
• This method features wizard mode, which may hide G-code or bypass its usage.
• This method enables for generating simple part programs within a short duration of 30 minutes for operators
• This is the input-only method and cares about the details.

Advantages of conversational programming

• Easy to learn and use
• No G-code
• Shortened setup and programming times
• Reduced errors and scrap.
• More cost-effective than CAM

Dis-Advantages of conversational programming

• Limited capabilities
• Cannot support complex tool paths
• Less flexible than CAM.

CAM system programming

• Most of designers use this method to manage the shortage of skilled workers as the price of the CAM systems drops.
• Though this method requires the operator to load basic information
• CAM system programming generates the G-code language responsible for controlling the CNC automatically to make user independent
• In some situations, this CAM system is handy for operators that have several different types of machine

Advantages of CAM system programming

• Doesn’t require detailed math calculations
• Uses automation to boost output
• Reduces machine crashing due to programming errors

Dis-Advantages of CAM system programming

• Still requires basic programming knowledge
• The operator does not have total control over the machining process
• Output less effective than manual techniques

Tips for CNC machine programming to beginners

The three tips for CNC programming for beginners.

Thorough revision of the fundamentals

• Getting through in fundamentals and staying in touch with it is the better way for CNC Programmers to begin their carrier.
• To ensure appropriate manual and conversational programming, the operators must be perfect with their math skills.

Customization of CNC machine feed rates

• Maximum time duration is spent in composing a program to ensure smooth functioning for high-volume CNC projects for greater efficiency, and consistency,
• Customization of certain CNC programming aspects optimizes the manufacturing process.
• Since code run by a CNC machine calls out a speed and a feed the machine tends to revert to its last set RPM if a CNC operator commands a spindle without providing a speed command.
• Operators must be flexible to adjust the feed times in accordance with the quality of the product.

Knowing the compensation types of a CNC machine

• Compensation includes allowing and accounting for the occurrence of unmatched variations.
• For a CNC milling machine, the operator may enter appropriate programming codes to calculate the values for making a perfect component, but accuracy and precision assurance is not provided until the machining phase is over.
• During the machining phase, the result is affected by variables such as tool pressure and is tedious.
• Generally, tool pressure affects the final product regardless of initial adjustments and calculations
• Operators can enter correction manually or by the program via automatic pre-setter tools within the CNC machine.
• With each adjustment, and compensation a machine can gain precision.

Some machining compensation type includes

• Cutter radius compensation,
• Tool length compensation,
• Tool wear, and
• Fixture offsets.

What kinds of programs are available for CNC?

Computer Numerical Control software creates a program code to control and guide a CNC machine. Programs are available for Computer Numerical Control

1. Aspire.
2. Easel.
3. AutoCAD®
4. Inkscape.
5. Marlin.
6. Fusion 360®
7. SolidWorks®
8. eCam.
9. GRBL
10. NC Viewer
11. Mach3
12. LinuxCNC
13. Universal Gcode Sender
14. PlanetCNC
15. OpenBuilds Control
16. OpenCNCPilot
17. TurboCNC
18. Machinekit
19. CNC Simulator Pro
20. G-Wizard Editor

How hard is it to program CNC?

• Learning beginner-level of programming is very easy, by understanding basic math must know about the working of CNC machines.
• CNC programming can be learned just in a few days.
• Learning Intermediate programming skills takes more time about 10 to 12 months.
• But learning advanced programming skills takes more time about a couple of years.

What are the codes used for CNC programming?

The CNC programming uses G code, & M code.

G codes

• It is the most popular CNC programming language.
• It directs for motion and function of the machine.
• The commands are in alphanumeric format
• The code starts with the alphabet G which stands for geometry.
• G-code is responsible for CNC machine movement.
• This code tells the machine about starting, moving, and stopping during fabricating a part.

G Code List

• G00: Rapid Position Motion
• G01: Linear Interpolation Motion
• G02: CW Circulation Interpolation Motion
• G03: CCW Circular Interpolation Motion
• G04: Dwell (P) P=Seconds. Milliseconds
• G05: Fine Spindle Control Motion
• G09: Exact Stop
• G10: Programmable Offset Setting

M codes

• M code starts with the letter ‘M.’ 
• The M code is a set of auxiliary commands where all non-geometric actions of the machine are controlled.
• Operators refer to these codes as miscellaneous codes, since non-cutting actions such as stopping programs, flooding the machine with coolants, and shutting down when temperature drops are controlled

M Codes List

• M00: Program Stop
• M01: Optional Program Stop
• M02: Program End
• M03: Spindle on Forward (S)
• M04: Spindle on Reverse (S)
• M05: Spindle Stop
• M08: Coolant On
• M09: Coolant Off
• M10: Chuck Clamp

What is the best CNC programming software?

Some kinds of CNC programming software involved in the machining process are shown below.

Computer-Aided Designing (CAD) software: 2-Dimensional, 2.5-Dimensional, or 3-Dimensional Designs are created.

Computer-Aided Machining (CAM) software: Converts the designs to machines G-code language.

Control Software: Reads the G-code and generates signals to control the stepper motor drives

Simulation Software: Reads the G-code and forecasts errors that may arise during machining

Fusion 360

• Fusion 360 is a cloud-based 3-Dimensional modelling software for CAD, CAM, CAE, and PCB software platforms for designing and manufacturing professional products.
• Designs the products as required in the form, fit, and function
• Save time and money
• Produces quality parts within a short period of time.
• Anything can be created by using comprehensive electronics and PCB design tools.

Fusion 360 with Power Mill

• Provides expert CNC programming for complex 3 and 5-axis manufacturing.
• It also includes access to advanced manufacturing capabilities through Fusion 360 extensions.

What are the steps of CNC programming procedure?

There are six steps for creating a CNC Program.

• Determining the machining operation to be performed.
• Determining the sequence of the process.
• Perform required mathematical operations.
• Fixture consideration.
• Consider using cutting tools.
• Document writing.