What is CNC Machining? A Comprehensive Advanced Guide to Computer Numerical Control Technology

Featured Image-What is CNC machining

CNC machining refers to a type of machining that utilizes Computer Numerical Control technology. Unlike traditional machining, which requires the operator to manually operate the machinery, CNC machining relies on computer programs to guide the cutting tools and create intricate and complex shapes with high accuracy.

CNC machining is a highly versatile manufacturing method that can be used to create everything from simple components to complex aerospace and medical parts. With its ability to create parts quickly and accurately, CNC machining has become an essential part of modern manufacturing.

In this article, we will find the world of CNC machining in-depth, looking at its applications, benefits, and the different types of CNC machines available. You’ll have a better understanding of how CNC machining works and how it can be used to create the precision parts and components your business needs after reading this article.

A bird's nest-shaped workpiece is being machined. This picture shows you visually what is CNC machining.
A bird’s nest-shaped workpiece is being machined. This picture shows you visually what is CNC machining.


Explanation of CNC machining

CNC machining is short for Computer Numerical Control machining. It is a manufacturing process involving computerized controls to operate and manipulate machining tools, such as drills, lathes, and mills, to cut and shape raw materials into finished products. The computerized controls allow for precise and complex cutting operations to be executed with high accuracy and consistency, resulting in high-quality and reliable end products.

A brief history of CNC machining

CNC machining has a rich history dating back to the late 1940s and early 1950s. During that period, the United States Air Force was in search of a method to fabricate precise and intricate components consistently. They developed the first CNC machine, which used punch cards to control movements. This machine was called the Numerical Control (NC) machine and was a significant leap forward in the manufacturing industry.

An Early CNC machine
An Early CNC machine

In the 1960s, the first computer-controlled CNC machines were developed, which allowed for more complex and precise machining operations. As computer technology advanced, so did CNC machines, leading to the development of 3-axis and 5-axis machines that could produce highly intricate and complex parts.

Advantages of CNC Machining

Increased precision

One of the principal benefits of CNC machining is the heightened precision it provides. CNC machines execute the cutting process through computer-controlled programs, resulting in a final product that is highly precise and repeatable. Traditional machining techniques rely on manual adjustments, which can result in minor final product variations.

A CNC machine can process high precision products
A CNC machine can process high precision products

In contrast, CNC machines can make precise cuts and hold tight tolerances. It is particularly important for aerospace and medical device manufacturing industries, where even small variations can have significant consequences. With CNC machining, parts can be produced to exact specifications, ensuring they meet the required standards and function as intended.

Machining parts for the automotive and aerospace industries with CNC machining processes
Machining parts for the automotive and aerospace industries with CNC machining processes

Another benefit of CNC machining is that it allows for greater consistency in the manufacturing process. Once a program has been created and tested, it can be used repeatedly to produce identical parts without requiring manual adjustments. Using CNC machining can minimize errors and save time by avoiding multiple setups.

Overall, the increased precision offered by CNC machining has revolutionized the manufacturing industry, creating complex and highly precise parts that were previously impossible using traditional methods.

Increased efficiency

CNC machines can perform tasks quickly and with a high level of accuracy, which helps minimize errors and reduce waste. Because CNC machines are automated, they can run for extended periods without needing to be stopped or restarted. Production can be carried out more efficiently and with less downtime.

CNC machines are also able to perform multiple operations at the same time, which further increases efficiency. For example, a CNC machine may be able to drill, mill, and cut a part in a single operation, which would require multiple machines or setups if done manually. By eliminating the need for multiple setups, CNC machining can save time and minimize the chances of errors and inaccuracies, making it a reliable and efficient manufacturing process.

Common milling operations
Common milling operations

Another way in which CNC machining increases efficiency is through the use of CAD/CAM software. This software allows manufacturers to design parts and create optimized toolpaths for the specific machine. The software can automatically generate the code needed to run the machine, eliminating the need for manual programming and reducing the risk of errors.

CNC machining’s higher efficiency results in quicker production of components with superior accuracy, thus diminishing costs and enhancing the quality of the finished product.


Compared to traditional manual machining, CNC machines require less human intervention, reducing the chances of errors and the need for frequent corrections. The use of automation in CNC machining also means that the production process can be completed much faster, leading to higher throughput and shorter lead times.

A CNC machine being machined at high speed
A CNC machine being machined at high speed

Additionally, CNC machining can be cost-effective in terms of material usage. CNC machines can optimize material usage by creating parts with minimal waste. This is because CNC machines can calculate the most efficient use of material and then cut the part accordingly, leaving minimal scraps or excess material.

Overall, the cost-effectiveness of CNC machining can lead to significant cost savings for manufacturers, making it a highly attractive option for businesses looking to optimize their production processes.


With the ability to use various cutting tools and techniques, CNC machines can create a wide range of parts with varying levels of complexity. CNC machining’s versatility enables designers to create parts with intricate geometries, which would be challenging or unachievable with traditional machining methods, granting greater design freedom. Additionally, CNC machines can produce parts from various materials, including metals, plastics, and composites, further expanding their applications.

CNC process can process complex shapes of parts
CNC process can process complex shapes of parts

Furthermore, CNC machines can easily switch between different jobs, which makes them ideal for small production runs or custom orders. CNC machines can be programmed to produce multiple parts simultaneously, reducing lead times and improving production efficiency. This adaptability makes CNC machining ideal for various industries, including aerospace, automotive, medical devices, and consumer products.

CNC Machining Processes


Turning utilizes a lathe to rotate the workpiece, while a cutting tool shapes the workpiece by removing the required material. This process is commonly used to create cylindrical shapes, such as shafts or bolts, and is also used to create symmetrical objects, such as gears.


Milling uses a cutting tool to remove material from a workpiece. The cutting tool is able to reach the material from multiple angles because the workpiece is fastened to a table that moves along the X, Y, and Z axes. Milling is a technique that can be utilized to fabricate intricate parts with complex 3D shapes.


With the cutting tool spinning and carving its way through the workpiece, you can create holes in any size or shape you desire. It’s time to drill like a pro! During CNC machining, the cutting tool rotates and moves into the workpiece, removing material and forming the desired hole shape and size.


An abrasive wheel is employed to eliminate material from a workpiece in the CNC machining process, known as grinding. The grinding wheel is rotated at high speed and is fed into the workpiece to remove material and create the desired shape. Grinding can create precise shapes and finishes and is commonly used to finish surfaces that other methods have machined.

Diagram of three types of machining: turning, milling, and grinding
Diagram of three types of machining: turning, milling, and grinding

Workflow of CNC Machining

Design and Programming

  • CAD/CAM software
  • 2D or 3D design
  • Toolpath creation
  • Simulation

Material Preparation

  • Selection of raw material
  • Inspection and quality control
  • Material handling and loading onto the machine

Machine Setup

  • Selection and mounting of appropriate tools
  • Machine calibration and alignment
  • Fixturing and clamping of the workpiece

Machining Operations

  • Cutting the workpiece using the programmed toolpath
  • Tool changes and adjustments as needed
  • In-process inspection and quality control

Post-Processing and Finishing

  • Removal of any burrs or excess material
  • Cleaning and deburring
  • Surface finishing, such as polishing or coating

Inspection and Quality Control

  • Final inspection and verification of specifications
  • Documentation and record-keeping of results

Shipping and Delivery

  • Packaging and preparation for transport
  • Shipment to the customer or next stage of production

Applications of CNC Machining

Aerospace industry

CNC machines create aircraft parts and components, such as engine components, fuselage parts, landing gears, and more. CNC machines are ideal for creating complex, precise parts in large volumes, making them perfect for aerospace manufacturing.

CNC machining in aerospace applications
CNC machining in aerospace applications

Medical industry

CNC machines are used to create medical implants, surgical instruments, and other devices. CNC machining ensures that the parts and components used in the medical industry meet the exacting standards required by healthcare providers.

Automotive industry

CNC machines create precision parts and components for cars, trucks, and other vehicles. They are used to manufacture everything from engine blocks and transmission parts to steering components and suspension systems. CNC machining helps ensure that the parts produced are of high quality and meet the exact specifications of the automotive industry.

Electronics industry

The manufacture of accurate parts and components for electronic devices, such as connectors, sockets, transformers, capacitors, resistors, and other similar devices, is made possible by CNC machines. CNC machining is ideal for creating complex, intricate parts with high accuracy, making it an essential tool for electronics.

Other industries

In addition to the abovementioned industries, CNC machining is widely used in other fields. For example, in the construction industry, CNC machines can create precise and intricate molds for building components such as wall panels, floor systems, and decorative elements. In the energy industry, CNC machining produces custom parts for turbines, generators, and other equipment.

CNC machining in the field of hardware
CNC machining in the field of hardware

The marine industry also benefits from CNC machining, as it creates accurate and durable components for ships and offshore structures. In the telecommunications industry, CNC machines can be used to produce components for antennas, satellite dishes, and other equipment. In the packaging industry, CNC machining is used to produce molds for packaging materials such as bottles, cans, and boxes.

Overall, the applications of CNC machining are diverse and wide-ranging, with technology playing a critical role in many different industries. Its ability to quickly and efficiently produce accurate, high-quality components has made it an essential tool in modern manufacturing.

3-Axis, 4-Axis, and 5-Axis CNC Machining

3-axis, 4-axis, and 5-axis CNC machining are different configurations of CNC machines that offer varying degrees of versatility and precision for manufacturing complex parts. The number of axes refers to the number of directions the cutting tool can move.

3-axis CNC machines

3-axis CNC machines are the most common type and are suitable for producing parts with relatively simple geometries. They have three axes of motion (X, Y, and Z) and can perform basic operations like drilling, tapping, and milling.

a 3-axis CNC machine
a 3-axis CNC machine

4-axis CNC machines

4-axis CNC machines have an additional rotational axis (A-axis) that allows the part to be rotated while machining. This enables the machine to perform complex operations like profiling and contouring.

GF+ 4-axis CNC machine
GF+ 4-axis CNC machine

5-axis CNC machines

5-axis CNC machines have two additional rotational axes (B and C) that allow for even greater flexibility and precision in machining complex parts with intricate geometries. The B-axis tilts the cutting tool, while the C-axis rotates the part, allowing the machine to access hard-to-reach areas.

Each type of CNC machine has its pros and cons and is better suited for specific applications. For instance, 3-axis machines are a cost-effective and user-friendly option, making them suitable for small-scale businesses or startups. However, if a higher precision level is required or the part is more intricate, then a 4 or 5-axis machine may be essential.

Overall, the choice of machine depends on the specific needs of the application and the complexity of the part being produced. CNC machining has revolutionized the manufacturing industry, allowing for greater precision, efficiency, and versatility in producing high-quality parts.

Don’t say a 5-axis CNC machine is better than a 3-axis one.

Types of CNC machines

Numerous CNC machines exist, each crafted to perform specific processes or tasks. Here are some of the commonly utilized ones:

Type of CNC MachineApplications
CNC Milling MachineProducing flat or curved surfaces, drilling, tapping, and boring operations
CNC LatheProducing cylindrical or tapered surfaces, drilling, and boring operations
CNC RouterCutting and shaping wood, plastic, and non-ferrous metals
CNC Plasma CutterCutting sheet metal, aluminum, and other conductive materials
CNC Electric Discharge Machine (EDM)Producing intricate shapes in hard metals, die and mold-making
CNC Laser CutterCutting and engraving various materials, like metal, wood, and plastic.
CNC GrinderGrinding and polishing of surfaces to high tolerances
CNC Drilling MachineDrilling operations, such as holes and thread tapping
CNC Turning MachineProducing cylindrical or tapered shapes, drilling, and boring operations
CNC Wire Bending MachineProducing complex wire shapes for various applications

CNC programming

CNC programming is a key aspect of CNC machining, as it involves creating the instructions that tell the machine how to move and cut the material. The programming can be done manually, using specialized software, or a combination of both.

The first step in programming a CNC machine is to create a CAD (computer-aided design) model of the part that needs to be machined. This model is then translated into a CAM (computer-aided manufacturing) program that generates the tool paths and cutting instructions for the CNC machine.

CNC programming software
CNC programming software

The programming process includes defining the tool paths, selecting the appropriate tools, specifying the cutting parameters (speed, feed rate, depth of cut, etc.), and ensuring that the machine is properly calibrated to achieve the desired level of precision. Once the program is completed, it is uploaded to the CNC machine and the machine executes the program to create the finished part.

Several programming languages are used in CNC machining, including G-code, M-code, and conversational programming. G-code is the most common language and is a standardized set of instructions used by most CNC machines. M-code is used for auxiliary functions, such as coolant control or tool changes. Conversational programming is a simplified programming method that allows the operator to program the machine using a series of prompts and menus rather than writing code manually.

G code sample of CNC machining
G code sample of CNC machining

CNC Machining Materials


Metals are common in CNC machining, especially in the aerospace, automotive, and medical industries. Different types of metals are used:

  • Aluminum
  • Brass
  • Copper
  • Stainless steel
  • Steel
  • Titanium
  • Zinc

These metals are chosen for their various properties, such as strength, durability, conductivity, and corrosion resistance. Different types of metals may require different machining processes and techniques to achieve the desired results. Still, CNC machining can handle a wide range of metal materials with precision and efficiency.


CNC machining commonly employs plastics for their adaptability, affordability, and ease of processing. Many different types of plastic materials are available for CNC machining, each with unique properties and applications. Some common types of plastic materials used in CNC machining include:

Plastic MaterialProperties
Acetal (Delrin)High strength, stiffness, and hardness; excellent dimensional stability; good wear resistance; easy to machine
AcrylicExcellent optical clarity and transparency; good impact resistance; easy to machine and polish; prone to cracking
NylonHigh strength and toughness; good wear resistance; excellent dimensional stability; absorbs moisture.
PolycarbonateGood impact resistance; excellent dimensional stability; high-temperature resistance; prone to scratching
PolyethyleneLow friction and good wear resistance; chemical resistance; excellent impact strength; low strength and stiffness
PolypropyleneGood chemical resistance; low density; excellent impact strength; low stiffness and temperature resistance
PTFE (Teflon)Very low friction; excellent chemical resistance; good electrical insulation; difficult to machine
PVCGood chemical resistance; low cost; good impact strength; prone to UV degradation
UHMWLow friction and good wear resistance; excellent impact strength; absorbs moisture; difficult to bond

These are examples of the diverse plastic materials available for CNC machining. By choosing the right material for a given application, manufacturers can achieve the desired performance characteristics while keeping costs low and ensuring ease of machining.

different kinds of plastic materials
different kinds of plastic materials


Composites are materials made of two or more different substances combined to create a material with enhanced properties. CNC machining frequently uses composites in aerospace and automotive industries due to their advantageous properties like high strength-to-weight ratio.

Some common composite materials used in CNC machining include carbon fiber-reinforced polymers (CFRPs), glass fiber-reinforced polymers (GFRPs), and Kevlar-reinforced polymers (KRPs).

Composite materials offer a high strength-to-weight ratio and are commonly used in applications that require both strength and lightweight, such as aerospace and automotive industries. However, composites can be challenging to machine due to their anisotropic properties, which can cause delamination and other defects if not machined properly. This technology can provide precise and consistent cutting of composite materials to avoid these issues and produce high-quality composite parts.

CNC vs. traditional machining

CNC machining has several advantages over traditional machining methods. One of the main advantages is increased precision, as CNC machines can produce more accurate and consistent parts. Additionally, CNC machines are highly efficient, as they can work continuously without requiring breaks or supervision. This efficiency can lead to lower production costs and faster turnaround times.

CNC high precision machining capability
CNC high precision machining capability

The versatility of CNC machining is noteworthy, as it enables the production of intricate shapes and geometries that would be challenging or unfeasible to produce with conventional machining techniques. Programming and automating the machining process allow for greater design flexibility and customization.

In contrast, traditional machining methods are often slower and less precise, requiring manual operation and adjustment. They may also be limited in producing complex shapes and geometries.

CNC machining provides various benefits over traditional machining techniques, which is why it is a favored option for numerous industries and applications.

The cost and ROI of CNC machining compared to other manufacturing methods

CNC machining has a higher upfront cost compared to traditional machining methods, but it offers greater efficiency and accuracy, which can result in lower costs over time. The price of a CNC machine can fluctuate based on its size, intricacy, and quality, as well as any necessary extra features or options.

The ROI for CNC machining depends on the application, industry, and production volume. In high-volume production scenarios, the increased efficiency and precision of CNC machining can result in significant cost savings over time, making the initial investment in a CNC machine well worth it. However, for low-volume or prototype production, the cost of a CNC machine may not be justified, and traditional machining methods may be more cost-effective.

The mill-turn CNC process that has exploded in recent years has amazing efficiency and ROI
The mill-turn CNC process that has exploded in recent years has amazing efficiency and ROI

It’s important to note that while CNC machining can be more expensive upfront, it offers a level of precision and quality that is difficult to achieve with traditional machining methods. CNC machines can operate longer with minimal human intervention, resulting in greater efficiency and throughput. Overall, the decision to invest in CNC machining depends on many factors, including production volume, industry, and specific application needs.

Future of CNC Machining

The future of CNC machining looks bright, with ongoing advancements in technology and the increasing demand for customized products.

Increased automation

According to a report by MarketsandMarkets, the CNC machine market is projected to achieve a value of $117 billion by 2027, with a compound annual growth rate (CAGR) of 7.2% from 2020 to 2027. This growth is primarily fueled by the expanding use of automation in the manufacturing industry, including the adoption of CNC machines.

Integration of artificial intelligence (AI)

Grand View Research’s report indicates that the global AI in the manufacturing market was valued at $513.6 million in 2020 and is forecast to grow at a CAGR of 41.2% from 2021 to 2028. AI technology integration has contributed to the significant growth of CNC machines, enhancing their capabilities.

Predicting CNC machine spindle problems using artificial intelligence
Predicting CNC machine spindle problems using artificial intelligence

3D printing and CNC integration

The hybrid 3D printing and CNC machine market is projected to reach $4.5 billion by 2027, with a 20.3% CAGR from 2020 to 2027, as per a SmarTech Analysis report.

Sustainable manufacturing

Allied Market Research predicts a CAGR of 10.6% from 2020 to 2027 for the sustainable manufacturing market, which is expected to reach $22.8 billion. Adopting sustainable materials and processes in CNC machining partly drives this growth.

Cloud-based manufacturing

As reported by Technavio, the global market for cloud-based manufacturing is projected to grow at a 27% CAGR from 2020 to 2024, attributed to the increasing adoption of cloud-based software and services in CNC machining and other manufacturing processes.

Increased use of robotics

As reported by ResearchAndMarkets, the global manufacturing industrial robots market was worth $18.05B in 2020 and is estimated to reach $30.8B by 2026, with a 9.2% CAGR from 2021 to 2026. This growth is partly driven by the increasing use of robots in CNC machining processes.


In summary, CNC machining has transformed the manufacturing industry, enhancing efficiency and cost-effectiveness. CNC machines’ increased precision, efficiency, and versatility have made them indispensable tools for various industries, including aerospace, automotive, electronics, and medical. With the use of CNC machines, manufacturers can create complex parts with tight tolerances, improving the quality of the end product.

Advancements in technology, automation, and robotics have contributed to the growth of the CNC machining industry, providing opportunities for increased productivity, efficiency, and accuracy. As the demand for customization continues to grow, the need for CNC machining will only increase in the future.

In summary, CNC machining has greatly influenced the manufacturing industry and its significance cannot be overstated. Its versatility, high precision, and cost-effectiveness make it an invaluable tool for manufacturers seeking to produce high-quality parts efficiently.

That’s pretty much the end of the introduction to CNC machining. I am Ray Liu. I have been working at Firstmold for over 10 years and have decades of experience in the industry. I am always here to assist you with any questions you may have about the machining industry. Don’t hesitate to reach out to me, and I will do my best to provide you with the answers and guidance you need.