CNC Milling: Definition, Processes, Types, Application

CNC milling is a process used to create complex parts and components by removing material from a solid metal or plastic block. It uses computer-controlled machines to shape and cut materials into specific shapes and sizes precisely.

This technology has changed the production industry by making it faster and easier to make complicated parts of high quality. This blog post will tell you everything you need to know about CNC milling, such as what it is, how it works, what it can be used for, and so on.

1. What is CNC Milling?


CNC milling, also known as computer numerical control milling, is a manufacturing process that involves the use of computer software and machine tools to produce precision parts and components. The process involves removing material from a solid metal or plastic block using a rotating cutting tool to create a specific shape.

CNC milling machines are highly versatile and can be used to create a wide range of parts and components, from simple designs to highly complex geometries.

2. How Does CNC Milling Work?


CNC milling is a precise and efficient manufacturing process used to create a wide range of parts and components. The process involves using computer-controlled machines to remove material from a workpiece to achieve the desired shape and size.

A CAD (computer-aided Design) model of the part is created using specialized software to start the process. The model is then loaded into the CNC milling machine’s computer, which guides the cutting tools in removing material from the workpiece.

The cutting tools used in CNC milling can vary depending on the material being machined and the desired finish. Common tools include end mills, ball mills, and drills.

As the cutting tools remove material, the machine’s computer monitors the process and makes adjustments as needed to ensure accuracy and precision. Once the milling process is complete, the finished part is removed from the machine.

3. Types of CNC Milling Operations


CNC milling processes can be categorized into several types based on the complexity of the operation and the tools used. Here are the most common types of CNC milling operations:

Face milling

Face milling is a machining process that involves cutting flat surfaces on the workpiece. The cutting tool, which is typically a large-diameter cutter, rotates perpendicularly to the surface of the workpiece, removing material in a sweeping motion.

Face milling can be used to produce flat surfaces, slots, and grooves on a variety of materials such as metal, plastic, and wood milling

Peripheral milling

This is a machining process where a cutting tool with multiple teeth rotates around the workpiece to remove material—the cutting tool moves along the outer edges of the workpiece, creating a peripheral cut. It is commonly used for cutting slots, grooves, and other features on the outer surface of the workpiece.

Slot milling

It involves the cutting of narrow slots in the workpiece. This process is commonly used to create grooves, keyways, and other features requiring precise, straight cuts.

Chamfer milling

Chamfer milling is a process in which the cutting tool creates a beveled edge or angled groove at the edge of the workpiece. This can be used to create a chamfer or to prepare the workpiece for welding.


Drilling is a machining process that involves creating a round hole in a workpiece using a rotating cutting tool called a drill bit. The drill bit is pressed against the workpiece and rotated at high speed, which cuts away material to create the hole.

There are several types of drilling, including twist, center, and deep-hole, each with its own specific application and technique.


Boring is a machining process used to enlarge or refine an existing hole in a workpiece. The boring tool is typically a single-point cutting tool that removes material from the workpiece as it rotates. The tool is guided by the existing hole or a pilot hole, and the cutting action occurs along the inner diameter of the hole.

Thread milling

This process is typically used for creating internal threads in a workpiece, such as those found in nuts and bolts.

4. Material Selection for CNC Milling


When selecting materials for CNC milling, it’s important to consider several factors to ensure a successful and efficient machining process.

  • Corrosion resistance: Depending on the application, choosing a material that is resistant to corrosion may be necessary. For example, stainless steel 316 is more resistant to use in the marine field.
  • Cost: Of course, the cost is always a consideration when selecting a material. Some materials, such as copper and titanium are more expensive than steel or aluminum alloys, and the machining cost may also vary depending on the fabric.
  • Operating temperature: If the part is used in a high-temperature environment, the material must be able to withstand those temperatures without losing strength or changing shape.
  • Part function: The part’s intended function can affect the material selection. For example, a more robust and durable material may be necessary if the role is subject to high stress or wear.
  • Tolerance requirements: The precision and tolerance required for the part can also impact material selection. Some materials may be more accessible to a machine to tight tolerances than others. However, it isn’t easy for plastic to keep tight tolerances compared with metal.

Below is the standard material that we could support.

Metals: Aluminum/Beryllium/Brass/Bronze alloys/Carbon steel/Copper/Iron/ Nickel/Stainless steel/Steel alloys/Titanium

Plastic: ABS/Acetal/Acrylic/Fiber-reinforced/Nylon/Phenolic/Polycarbonate/Polyetherketone/PTFE/PVC/Teflon

Wood: soft wood/hard wood/engineer wood

5. Advantages of CNC Milling


CNC milling offers several advantages over conventional machining methods. Here are some of the main benefits of using CNC milling:

  • Precision: CNC milling machines can achieve a very high level of precision and accuracy, which is critical for applications that require tight tolerances. Many aerospace parts need at least 0.001mm tolerance, so CNC milling is the top 1 option.
  • Consistency: CNC milling is well for mass production. This consistency is achieved through pre-programmed computer software that ensures that each part is produced identically to the others, with no variation in quality or dimensions.
  • Flexibility: CNC milling machines can be programmed to produce a wide range of complex shapes and parts, making them highly versatile. This is because they can be programmed to cut and shape legs in any number of ways, allowing for highly complex designs and shapes to be produced quickly and accurately.
  • Efficiency: CNC milling machines can operate continuously, with minimal downtime, allowing for higher productivity and throughput levels. This is because they do not require the same level of manual intervention as conventional machines, allowing them to operate for longer periods without human intervention.
  • Cost-effective: While the initial cost of a CNC milling machine may be higher than a conventional machine, the long-term cost savings can be significant due to the increased efficiency and productivity. This increased productivity means that parts can be produced quickly and with less waste, resulting in lower overall costs.

6. Disadvantages of CNC Milling


While CNC milling machines offer many advantages, there are also some disadvantages. Here are some of the main disadvantages of CNC milling:

  • High initial cost: CNC milling machines can be more expensive to purchase and set up than traditional machines, which can be a barrier to entry for some businesses.
  • Maintenance and repair costs: CNC milling machines require regular maintenance and repair, which can add to their overall cost.
  • Skilled operator required: CNC milling machines require experienced operators who are knowledgeable about programming, machining, and tooling.

7.Applications of CNC Milling


Industry Application
Aerospace Aircraft engines, frames, and other components.
Automotive Engine blocks, transmission cases, and suspension components.
Medical Implants, surgical tools, and prosthetics.
Electronics Circuit boards, enclosures, and connectors.
Mold making CNC milling is used to create molds for casting and injection molding processes used in the production of plastic and metal parts.
Architecture Architectural models, sculptures, and decorative elements.
Furniture Tabletops, legs, and frames.

8.Types of CNC Milling Toolings


Industry Application Photo
Aerospace General purpose milling of flat surfaces, slots, and pockets
Ball mill Machining of complex 3D contours and shapes, such as molds and dies
Chamfer mill Creating beveled edges and chamfers on workpiece edges
Face mill Removing material from large flat surfaces
T-slot mill Cutting T-shaped grooves in workpiece surfaces
Thread mill Machining threaded holes and surfaces
Drill mill Drilling and milling in a single operation

9. CNC Milling Software


CNC milling software is critical in controlling the machine’s movements and ensuring the final product is accurate and precise. Here are some vital aspects of CNC milling software:

CAM (Computer-Aided Manufacturing) software creates the tool paths and instructions for the CNC machine to follow.

CAD (Computer-Aided Design) software is used to create the initial design or model of the part. Simulation software allows the user to visualize and test the milling process before running the machine, reducing the risk of errors and wasted materials.

Simulation software allows the user to visualize and test the milling process before running the machine, reducing the risk of errors and wasted materials.

Post-processing software converts the tool paths generated by CAM software into machine code that the CNC machine can understand and execute.

Some CNC milling machines may come with proprietary software specific to that machine, while others may use open-source software that can be customized to meet the user’s needs.

10. Factors Affect CNC Milling Cost


  • Material Costs: The cost of the material being milled is a significant factor in CNC milling costs. The price of raw materials can vary greatly depending on the type, quality, and quantity needed for the project.
  • Machine Time: The amount of time a CNC milling machine is in operation will also impact the cost. This includes the setup time to prepare the device for milling and the actual milling time. Longer milling times will increase the cost.
  • Tooling Costs: CNC milling tools, such as cutters and drills, can be expensive, especially if they are made of high-quality materials or have specialized coatings for improved performance. Tooling costs will also depend on the complexity of the project and the number of tools needed.
  • Labor Costs: The labor cost for CNC milling will depend on the skill level and experience of the machinist operating the machine. More complex projects may require more skilled labor, resulting in higher labor costs.
  • Overhead Costs: Overhead costs, such as rent, utilities, and insurance, can also affect the cost of CNC milling. These costs will vary depending on the size and location of the machining facility.
  • Design Complexity: The complexity of the Design being milled will impact the cost, as more complex designs require more time and effort to program and mill.
  • Quality Requirements: If high-quality and precise milling is required, this can increase the cost as it may require more time, labor, and specialized tooling.
  • Quantity: The number of parts being milled will also affect the cost. Generally, larger quantities result in lower per-unit costs due to economies of scale.
  • Shipping Costs: Shipping costs can also impact the overall cost of CNC milling. If the parts need to be shipped to the customer, the shipping cost will need to be factored into the total cost.

11. Types of CNC Milling Machines


Vertical milling machines

A vertical milling machine rotates the cutting tool, known as the milling cutter, while it moves vertically along the machined material.

The machine can also move the material being machined in different directions, allowing for precise cuts and shaping. The spindle, which holds the milling cutter, can be adjusted vertically to accommodate different depths and angles of cuts.

The cutting process is controlled by a computer program, ensuring accuracy and consistency in the final product.


Horizontal CNC milling machines

Horizontal CNC milling machines are similar to their vertical counterparts, but their cutting spindle is horizontally oriented. The workpiece is mounted on a horizontal spindle, which rotates at high speeds while the cutting tool moves along the X, Y, and Z axes.

The spindle and cutting tool is mounted on a carriage that moves along the bed of the machine, allowing for precise cuts to be made in various directions. Like vertical milling machines, horizontal machines can also be programmed with computer software to control the cutting process and produce exact parts.

Horizontal machines are often used for more extensive, heavier workpieces requiring a sturdy machine structure.


Multi-Axis CNC Milling Machine

2-axis milling machine

A 2-axis milling machine works by moving the workpiece in two directions (X and Y) while the cutting tool remains stationary. This results in two-dimensional cuts on the surface of the material.


3-axis milling machine

A 3-axis milling machine operates by moving the workpiece in three dimensions: X, Y, and Z. The cutting tool remains fixed vertically, while the workpiece is moved horizontally and vertically beneath it. The machine can create precise cuts, holes, and slots in a variety of materials.

4-axis milling machine

A 4-axis milling machine is similar to a 3-axis machine but also has a rotary table that allows for the fourth axis of rotation. This additional axis enables the machine to perform more complex operations, such as cutting at different angles and creating more intricate shapes.

The rotary table can rotate in both the X and Y directions, allowing for greater flexibility in the milling process. This type of machine is commonly used in the aerospace and automotive industries for the production of complex parts.

5-axis milling machine

A 5-axis milling machine has the capability to move the cutting tool in five different axes, directions simultaneously. These directions include the traditional X, Y, and Z axes and two additional rotary axes, which allow the cutting tool to be tilted and rotated. This gives the machine greater flexibility and allows it to produce more complex parts with greater precision.

12. CNC Milling Machine Components


CNC milling machines are made up of several key components that work together to achieve precise and efficient machining operations. These components include:


Control panel

This is the user interface for the machine, where the operator inputs the instructions for the milling process.



The spindle is the motor that drives the cutting tool and rotates it at high speeds to remove material from the workpiece.


Tool holder

The tool holder is the component that holds the cutting tool in place and provides a connection between the spindle and the tool.



The table is the work surface on which the workpiece is mounted and secured during milling.


Axis system

CNC milling machines use a coordinate system to control the movement of the cutting tool and workpiece along the X, Y, and Z axes.


Linear guides

Linear guides are used to guide and support the movement of the cutting tool and workpiece along the axes.


Coolant system

A coolant system is used to cool the cutting tool and workpiece during the milling process, which helps to improve tool life and prevent workpiece distortion.


Chip management system

Chips and debris produced during milling are managed and removed from the machine using a chip conveyor or other chip management system.


Safety features

CNC milling machines are equipped with various safety features, such as emergency stop buttons and safety interlocks, to ensure safe operation of the machine.

13. Future of CNC Milling


The future of CNC milling looks promising as advancements in technology continue to improve machine accuracy, speed, and automation. Machine learning and AI integration can optimize manufacturing, reducing costs and lead times. The use of additive manufacturing techniques, such as 3D printing, in combination with CNC milling can expand the possibilities of Design and production. With the rise of Industry 4.0, CNC milling machines are becoming increasingly connected and capable of remote monitoring, predictive maintenance, and data analysis, further enhancing their efficiency and productivity.

14. Contact Worthy Hardware’s CNC Machining Services


Worthy Hardware is a professional CNC machining service provider with competitive pricing. We offer a wide range of CNC machining services, including CNC milling, turning, drilling, and tapping. Our team of experienced engineers and technicians are equipped with advanced machinery and tools to deliver high-quality CNC machining products to meet our customers’ specific requirements.

We are committed to investing in the latest CNC machining technology to stay at the forefront of the industry and provide our customers with the most advanced and efficient machining services possible. Our services are suitable for a wide range of industries, including aerospace, automotive, medical, and electronics.

Contact us today to learn more about our CNC machining services and how we can help you bring your projects to life.

Worthy Hardware is a CNC manufacturing and sheet metal fabrication company,including CNC machining services,CNC milling services, CNC turning services, laser cutting services and stamping services.Call us +86-76989919645 or email us [email protected] for more discounts for your projects.