What Does Computer Numerical Control Mean?
Computer Numerical Control is an automated technology that controls mechanical tools with pre-programmed computer software. A single tool can execute multiple functions with a custom computer program. Moreover, you can modify the program to alter the outcome of the process without changing the equipment.
Numerical in the concept of CNC indicates the technology’s ability to use numbers in controlling the mechanical tools. These numbers may represent Cartesian coordinates, degrees, speeds, or other denominations. Machine tools read these numbers according to the commands in the program.
CNC has changed production processes across all manufacturing industries. This technology is compatible with all industrial processes, including 3D printing, welding, grinding, and cleaning.
How Does CNC Technology Work?
Computer numerical control machining works with a unique computer-aided design. Every part made with computer numerically controlled technology has a CAD program. The CNC system uses CAD software to develop the program for the needed process. As such, you can make minor changes like part dimension modification by editing the values in the program.
Then, you have to process the program into CNC machine-understandable language known as the G-code. The resulting files here are known as the CAM (computer-aided manufacturing) models. CAD models comprise instructions on how the components of the CNC machines should function.
Basic Components of a CNC System
CNC systems consist of various components, all of which function collectively. Here are these basic components:
CNC Controller: The controller or the Machine Control Unit (MCU) serves as the CNC machine’s brain. It commands the machine tools after reading the CAD software programs. The CNC controller provides automated commands such as the rotation of drills, the robotic arm’s movement, etc.
CNC Software: CNC software is the communication mechanism between the product manufacturer and the control system. Manufacturers use CAD software to design the intended part’s graphical representation. Meanwhile, the computer-aided manufacturing (CAM) software helps turn the CAD design into a machine-readable file for CNC machines.
Input/Output (I/0): Input devices including keyboard, mouse, and cursor. Machine operators use them in CNC machine setup. On the other hand, output devices are alarms and display monitors that display vital information like machine status and errors.
Communication Protocol: Communication protocols are the means through which any CNC machinist sends information to a CNC machine. For example, after the CAD files have been drafted, they must be programmed into the CNC machine. You can only do this through communication protocols like USB, Ethernet, RS232, RS422, etc. Also, the communication protocol can send data from a CNC system to a central server.
How Does the CNC Technology Guide the Movement of CNC Machine Tools?
Computer numerical control technology guides the movement of CNC machinery in three major ways. We’ll discuss these movements below:
Straight Line Motion
Straight line motion or liner interpolation is a positioning method whereby the machine tools move parallel to the X and Y axes. No diagonal movement occurs in this positioning method. The control system recalibrates after each positioning and begins the next linear movement. Although linear positioning is easy to program, it is slower than rapid motion.
Rapid Motion
Rapid motion positioning, also called point interpolation, is another machine tool positioning method. Here, the machine tool moves to the destination via the shortest possible distance. This positioning system uses the maximum speed of movement. Hence, it allows for faster production. Nevertheless, you must program the CNC machine tool carefully to mitigate the possibility of accidents.
Circular Motion
The circular positioning system rotates the machine tool around a central axis in a round manner. This positioning system is suitable for working round objects like cylinders or hole punching.
Coding in CNC
CNC machine operators communicate with CNC systems using CNC programming language or coding. Programming is a primary requirement in machine automation since “computer” is added to numerical control.
Modern software programs are innovative. It is vital to learn code language for effective CNC programming. You can create the model and use the software code generator to change it into machine language. You have to debug the code that is generated automatically to prevent errors. ‘G-code’ and ‘M-code’ are the principal codes important to CNC programming.
What Does G-code Mean in CNC?
G-code means Geometric code. It provides the machine tools with instructions on how to move. The G-code dictates all location parameters, including the tool’s start point, the endpoint, and the path between them.
The semantics of the G-code often vary even though all CNC machine tools use the G-code. The number of zeroes or the presence and absence of spaces mark the difference in the semantics of the G-code. Below are standard CNC G-code programs:
- G: provides the tool with start and stop instructions
- F: instruct the feed rate
- N: indicates the line number
- S: provides the speed of the spindle
- R: provides the cutting tool with the arc radius
- T: provides instruction on the type of tool to use
- X, Y, and Z: indicate the Cartesian coordinates for the location
Each command can possess a further sub-command. Common examples of these commands for positioning include:
- G00: Reach the preferred position in rapid motion
- G01: Reach the indicated position in linear motion
- G02: Form a clockwise arc with a preferred radius
- G03: Make an anticlockwise arc with a preferred radius
However, it would help to note that some systems can indicate the above commands as G0, G1, G2, and G3.
What Does M-code Mean in CNC?
M-code determines various functions of the machine that are unrelated to the positioning or working of the machine tools. M-code written in numeral control represents machine code or miscellaneous code. For instance, machine programmers use the M-code to control the coolant flow or automatically change the tool.
M-codes are like the G-code; they sometimes vary in semantics. For example, some machine tools can accept the command M01, while others require the M-code to be written as M1. Below are typical M-codes machine operators use:
- M00: Pause program execution halfway
- M01: Optional stop in program execution
- M02: Program end
- M08: Begin coolant flow
- M09: Stop coolant flow
What Are the Various CNC Software Used in CNC Machining?
CNC machine software can be categorized into the following classes
Computer-Aided Design (CAD)
Computer-aided design (CAD) software possesses the features and tools required to design the final product. You can draft the design in 2D and 3D. You can develop 2D shapes with vector base drawings. For 3D shapes, you can use solid and surface modeling to design them. CAD software is available with several additional features, such as:
- Visualization
- Ability to include cable routing in the design
- Auto-generation of regular design elements
- Examining the final part’s mass properties
Computer Aided Manufacturing (CAM)
CAM software programs can guide the numerical control machine tools without human labor. These programs have the same language as the CNC software embedded language. Modern CAM software programs comprise additional features such as gathering feedback data from CNC tools. The data can detect issues and help optimize the production rate.
Computer-Aided Engineering (CAE)
Computer-aided engineering software programs are less popular than CAD and CAM software. CAE software is valuable in handling complex engineering parts. CAE software helps in examining the mechanical characteristics of the parts. The CAE software programs allow you to visualize thermal properties, physics, strength, and stress.
Typical Processes that Use CNC Systems
CNC systems are different processes across several industries. Below are typical CNC operations that use computer numerical control:
CNC Turning
The CNC turning process removes material from a rotating workpiece with a non-rotary cutting tool. The cutting tools press against the rotating workpiece to cut material from it. As such, the movement forms a circular or helical design on the workpiece. CNC turning is best used for machining aluminum tubes, cylinders, pipe joints, and shafts.
CNC Milling
The CNC milling process uses a cutting tool placed on a rotary spindle to remove material from a workpiece. The table can be rotary or stationary. Moreover, machinists’ CNC systems on milling machines can possess multi-axis capabilities.
5-axis and 6-axis CNC mills make precision parts for medical, aerospace, and military industries. Besides, CNC milling machines are compatible with metals, plastics, wood, alloys, etc.
CNC Grinding
This manufacturing process involves using rotary abrasive wheels to remove material from a workpiece. CNC grinders work by smoothening the workpiece surface, adding high precision. Also, these grinders can remove sharp corners and edges from machined parts. Manufacturers across industries often use CNC grinding as a finishing technique.
CNC Waterjet Cutting
CNC waterjet cutting is an advanced process that removes material from a workpiece with the force of high-pressure water. The water pump pressures the water to about 30,000 to 90,000 psi, which is enough pressure to pierce different CNC materials, including metals, glass, wood, and alloys, except diamonds. It is a cold-cutting process with a high level of accuracy. The CNC control system dictates the water nozzle’s movement.
Electrical Discharge Machining (EDM)
The CNC electrical discharge machining process uses electrical pulses between two electrodes to remove material from a workpiece. The electrode pulses form an electrical arc that melts the material at the preferred location. Although CNC EDM processes provide accurate results, they are only compatible with metals because they conduct electricity.
CNC Laser Cutting
This machining process uses the high energy of a laser beam to cut material from a workpiece. The CNC laser is an exceptionally accurate cutting tool. Its laser beam has a width less than human hair and an extremely high frequency. The CNC control system moves the laser beam along the specified path precisely. It can work on metals and non-metals.
CNC Routing
CNC routing uses a rotating blade guided by the CNC machine to cut a workpiece. The rotating blade extends below the worktable’s base to make straight cuts on the workpiece. The CNC router is a computer-controlled system commonly used in the furniture and interior industries for engraving, milling, and cutting. Intricate wood carving on furniture and doors is a typical example of CNC routing capabilities.
CNC Plasma Cutting
This machining operation involves using ionized gasses to make desired cuts on the workpiece material. CNC plasma cutting is best suited for working with conductive materials such as aluminum, copper, and steel. Metal fabrication shops and automotive industries often use this cutting technique to create different parts and components.
3D Printing
3D printing is a standard method used to produce polymer parts. CNC systems control a nozzle that melts the polymer filament and shapes it into preferred shapes and sizes. CNC 3D printing is achievable in small-scale workshops and large-volume manufacturing processes due to the ease of operation and scalable size. However, 3D printing is compatible with only thermoplastics.
CNC Welding
CNC welding merges automation of CNC machining with manual welding technologies. CNC machines control the movement of the welding electrode and guide it across the workpiece. This process forms highly accurate and strong welds where needed. CNC welding is a fast and reliable process that eliminates labor requirements. However, it is only compatible with electrically conductive CNC materials.
Advantages of Computer Numerical Control Technology
CNC technology offers a broad range of benefits over manual machining processes. Here are the expected benefits:
Speed: CNC systems can manipulate machine tools faster than humans can. Hence, they can ensure efficiency and increase production since there are no breaks between movements.
Self-Diagnostics: Computer numerically controlled systems often detect and report errors within themselves. The self-diagnostic system alerts the operator promptly when it identifies an error. These diagnostics help prevent accidents such as program conflicts, machine breakdown, overheating, and workpiece damage.
Customization: CNC programming is highly customizable. You can program the same CNC machine tool to execute many different tasks. For example, a CNC machine tool can cut a solid cylinder and a solid sphere by changing to a different program.
Error Compensation: CNC machines can anticipate and compensate for machining errors by modifying tool movements. It occurs in real time with intelligent machine calculations. Consequently, you can easily achieve high precision in materials with geometric or thermal complications.
Compliance: Manufacturers have to meet stringent quality standards like ANSI and ISO. CNC technology offers the high precision required to meet every compliance standard.
Safety Measures: Each CNC machine has multiple measures to ensure the safety of the CNC operator and the workplace. Similarly, there are emergency stops that you can use when an unwanted event occurs.
Scalable Solution: CNC systems do not possess size restrictions. CNC machines can work on parts with sizes as small as that of a screw thread. They can also work on complete aircraft frames. Similarly, you can adjust the production rate to meet demand.
Complex Geometry: CNC technology can use complex tools and multi-axis machines to develop highly complex parts. As such, CNC machining makes parts with intricate internal geometry.
Quality Control: Computer numerically controlled systems possess inbuilt quality control measures. The sensor can inspect every machined part and reject it if it fails to meet the required standards.
Common Industries That Use CNC Technology
Every industry relies on computer numerical control systems. CNC technology either makes the tools used in the manufacturing processes of these industries or the CNC machines directly create the final product for the industry. Below are typical industries that use CNC technologies:
- Aerospace Industry
- Automotive Industry
- Architecture
- Furniture Industry
- Healthcare Sector
- Electronics Industry
- Construction Industry
- Military Sector
- Marine and Shipbuilding
- Jewelry Industry
- Robotics
- Rubber Products
- Paper Industry
- Metal Fabrication Industry
- Food and Beverage Industry
- Glass Industry
- Oil and Gas Industry
- Industrial Machinery
How Do CNC Technologies Optimize Efficiency in Production?
The high efficiency of computer numerical control machining is one of the reasons why manufacturers across industries embrace the technology. CNC machine tools can continuously execute tasks around the clock without needing breaks and sleep.
Unless there is a bug in the program or the machine operator makes a mistake with the setup, the computer numerical control systems will not make an error. Hence, do-overs won’t be required. Furthermore, CNC technology offers optimum efficiency and production rate than any other manufacturing process.
Future of CNC technology
CNC technology has paved the way for immeasurable possibilities in product manufacturing. Below are some of the advancements in CNC machining:
Artificial Intelligence
Infusing Artificial Intelligence with CNC technology is vital to its growth. CNC machines can learn from machining operations and provide reliable feedback to improve manufacturing processes, removing any obstruction. Moreover, multiple CNC systems can be combined in a single manufacturing line and controlled remotely via digital channels.
Virtual Reality
Virtual reality in CNC systems is an essential tool in operator training. It helps operators learn about the machine features in a virtual environment similar to a real-world setting. You can quickly learn without any risks of accidents involved with operating the machine. Additionally, you can test the different complex features of modern CNC machines without the risk of machine malfunction.
Robotics
Integrating CNC technology and robotics forms advanced machinery, pushing beyond the possible limits. Any manufacturing industry can now make parts in a fully automated manner from start to finish. Besides, robotic arms can handle the loading and unloading of machined parts. Manufacturers have also been able to increase machine precision and productivity with the integration of robotics.
Conclusion
Computer numerical control has remained a significant breakthrough in modern manufacturing processes. CNC systems possess unique capabilities that make them indispensable to every manufacturing setup. CNC machining offers an extensive option to meet the requirements of your project, irrespective of the complexities involved.
AT-Machining is a reliable modern machine shop with years of experience producing high-quality parts for different industries. Our CNC shop hosts modern machines like laser and waterjet cutters suitable for handling complex part designs with the utmost designs. Submit your CAD file today for instant quotes. Contact us today, and let us handle your next machining project!
