What is CNC Milling and How Does It Work: Everything You Need to Know

What is CNC Milling and How Does It Work- Everything You Need to Know

You must be familiar with different processes for producing precise parts, such as 3D printing and CNC machining. But do you think CNC milling is an advanced method for precise part manufacturing?

You must be wondering – how?

With modern technological advancement, this process has become an efficient method to produce high-volume parts accurately and precisely.

From the electronic industry to the consumer market, CNC milling is rapidly growing at a CAGR of 8.72%, with the forecast of expanding the market size to USD 21.55 Billion in the next two years.

Although manufacturing professionals are well aware of the exceptional advantages and uses of CNC milling; however, beginners and newbies are not much familiar with the process.

But don’t worry!

In this comprehensive guide, we will answer all your possible questions about CNC milling, how it works, its tools and machinery, and why you should choose this advanced process for your next project.

So, without any further delay, let’s get straight to it.

What is CNC Milling?

People often confuse CNC milling with CNC machining and CNC turning. Although all three processes are computer controlled, the processes have distinctive dissimilates in the working principles and range of application.

It is an advanced machining process that combines computer-controlled machines and milling cutters to produce complex parts of metal, plastic, glass, and wood.

It is a well-known CNC machining process that uses Computed Aided Design (CAD) software to design parts according to the pre-fixed pattern requirements.

The computer numerically controlled system provides a set of digital instructions allowing the machines to precisely cut the material by following the pre-patterned design.

Do you know that the demand for CNC milling in industrial sectors has been growing immensely significantly after the recent shift towards automated manufacturing systems?

The CNC milling method is different from other traditional manufacturing methods because the process works by mounting the workpiece and removing the material with a sharp multi-point cutting tool to produce the desired product.

However, products are produced by adding the material in other processes, such as 3D printing and additive manufacturing.

It is an efficient and convenient alternative because it offers faster run time and high parts precision. If your application requires high precision for large-volume runs, CNC milling has something to offer with its potential benefits and wide range of applications.

How Do CNC Milling Machines Work?

How Do CNC Milling Machines Work

CNC Milling machines are advanced equipment handled by a computer numerical control system. The milling machines cut and shape the mounted workpiece with the help of CAD-processed design.

Since the computer program guides these machines, their operation is synchronized and error-free. CNC milling machines are available in different sizes and configurations to fulfill your high industrial demand.

Horizontal vs. Vertical CNC Milling Machine:

CNC milling machines come in two different types based on the configuration of the part, Horizontal and Vertical CNC Milling Machines.

Although both machines work on the exact mechanism, some of the salient differences are discussed below:

  • Horizontal CNC Milling Machine: These machines employ short and thick multi-point cutting tools; thus, they are ideal for hard and thick-walled parts. In this type, the spindle is placed horizontally on the side of the milling machine. It provides less lead time with high accuracy. It is an expensive machine but lasts longer with low average maintenance.
  • Vertical CNC Milling Machine: In contrast, the spindle is placed vertically attached to the top of the machine. It has long, slender cutting tools suitable for less deep operations where precise detailing is required. It is less expensive than horizontal milling machines with low maintenance rates.

These machines can manufacture highly precise finished products without human intervention, but different mailing processes provide a different level of precision and accuracy.

Machining ProcessesTolerance Level (inch)
Standard Milling Machining± 0.005
Fine Milling Machining± 0.001
Specialized Machining (Polishing)± 0.00005
Different CNC Milling Machining Processes and Their Tolerance Level

CNC Milling Process:

CNC Milling Process

CNC milling is a sophisticated process that involves different steps and proper handling expertise. This specialized method involves various crucial steps to manufacture a high-quality end product.

Let’s break them down into 5 steps:

Step 1: Creating CAD Design:

In the first step, the engineers use special computer-aided design (CAD) software to create a 360-degree model. The model serves as a blueprint for the milling machine to produce the final product.

Step 2: Programming the CAD Model:

Step 2- Programming the CAD Model

In the next step, the operator will program the CAD model into computer-aided manufacturing (CAM), allowing the CNC machines to follow the instruction according to the design specification.

This digital information is called G-codes determining the movement and speed to produce specific workpieces.

Step 3: Setting Up the Machine:

Once the design has been programmed, the expert mechanists will set the CNC milling machines with appropriate cutting tools required to perform specific tasks.

They carefully attach the selected cutting tool with the machine spindle and place the workpiece accurately on the machine bed for processing. The operator also calibrates the alignment of the blueprints and machining components.

Step 4: Machining the Component:

Step 4- Machining the Component

The machining process begins after setting the machine properly. The machine follows the blueprints processed by the CAM software to precisely cut the material and carve the workpiece along with the axes. It is a repeated process and continues till the desired outcome is attained.

Step 5: Finishing & Inspection:

The staff members perform additional finishing work by sanding, polishing, or removing the rough edges from the workpiece.

Lastly, a detailed inspection is executed to ensure design specifications are fulfilled, and the final product meets the quality standards. The QC team determines this process’s tolerance, dimensions, and surface smoothness.

What Are the Axes of Motion on a Typical CNC Milling Machine?

What Are the Axes of Motion on a Typical CNC Milling Machine

A milling machine spindle rotates and subtracts from the workpiece by drilling or cutting to get desired final product. Based on the precision outcome, milling machines come in 3-axis, 4-axis, and 5-axis machines.

Let’s understand the difference between the 3, 4, and 5-axis milling machines.

3-axis CNC Milling Machine:

The 3-axis CNC milling machine can move in three axes (X, Y, and Z axis). This machine allows the product dimension in horizontal, vertical, and depth. It is usually employed for simple 3d design as it moves straight in three directions.

4-axis CNC Milling Machine:

4-axis CNC Milling Machine

The 4-axis CNC milling machine is similar to the 3-axis machine but consists of one rotatory axis called A-axis. So, it consists of X, Y, Z, and A (rotatory axis) for movement control.

The additional A-axis is specified for rotating the multi-point cutting tool to achieve precision while manufacturing complex components.

5-axis CNC Milling Machine:

5-axis CNC Milling Machine

Similarly, the 5-axis CNC milling machine is similar to the 4-axis machine with a second rotatory axis called the B-axis. Thus, this machine comprises X, Y, and Z and two rotatory axes (A-axis and B-axis).

In addition to the rotation, the B-axis allows the cutting tool to tilt around the workpiece to shape highly complicated designs. It is ideal for producing helical, cylindrical, and intricate shapes.

Looking for more detailed information?

Read out: 3-Axis to 12-Axis: CNC Milling Machine Capabilities Compared and Applications.

What Are the Advantages of Computer Numeric Control for CNC Milling?

What Are the Advantages of Computer Numeric Control for CNC Milling

As we all know, a computer numeric control system is a fully automated computer program that utilizes a 3D digital model to get the desired outcome. But do you know that before CNC technology, the milling process was controlled manually by skilled operators?

The operating staff moved the workpiece manually with the cutting tool to precisely cut the material. However, manual milling was time-consuming, error-prone, and expensive, with high demand for human interference.

But, with technological advancement, CNC milling has become an ideal alternative with its modern features and advantages.

Let’s have a deep insight into the advantages of computer numeric control (CNC) milling:

1. Enhanced Efficiency:

The CNC process is based on a computer program, enabling high efficiency and productivity without human intervention. Once the design is programmed in the milling machine, it allows you to create different complex parts automatically in less time.

2. Flexibility:

The process is compatible with making different complex parts with a wide range of material options. Therefore, it is a versatile process that gives you design freedom and material selection.

3. Improved Accuracy:

Improved Accuracy

Production errors and faults are the biggest turn-offs in any process. But accuracy is the most prominent advantage of the CNC milling process. It is capable of producing highly complex parts with accuracy and consistency without using expensive equipment or machinery.

4. Improved Safety:

Earlier, safety risks due to human errors and carelessness were the major threats to the milling machining process. The CNC milling machines are equipped with safety protocols and preventive measures, reducing the chances of accidents, machinery failure, injuries, and fatalities at the workplace.

5. Reduced Cost:

Reduced Cost

The CNC milling process does not demand high operating staff and heavy machinery. Only minimum supervision and operation staff are required to carry out the process.

What Are the Benefits of Automatic Tool Changers for CNC Milling Machines?

What Are the Benefits of Automatic Tool Changers for CNC Milling Machines

In CNC milling operation, the cutting tool requires several tools to make cuts according to the programmed design. Different tools are required for specific functions, from cutting the material to final finishing. However, changing the tools manually sounds very inefficient and increases the downtime of the process.

Therefore, manufacturers use automatic tool changers for CNC milling machines which can hold up to 30 tools in a carousel and change them in a matter of seconds when required.

An automatic tool changer (ATC) is an effective way to decrease downtime and increase the efficiency of the process. ATCs pre-load the tools required in operation and exchange them automatically on the spindle within seconds.

Looking for ways to cut down the cost of the CNC milling process?

Read out: How to Reduce CNC Milling Costs? – Overview and Tips to Cut Your Expenses

What Are the Different CNC Milling Methods?

What Are the Different CNC Milling Methods

There are different CNC milling methods manufacturers use for different industrial requirements. However, each method has its advantages, disadvantages, and specified application.

So, if you are confused about which method is suitable for your application, we have got you covered!

Here are the four most common CNC milling methods and their specifications:

1. Plain Milling:

Plain milling is the most common and affordable CNC milling method used to create a flat surface. In this process, the cutting tools move perpendicular to the workpiece to remove the unwanted material on the flat surface. This method is used to manufacture large flat components conveniently and efficiently. 

2. Angular Milling:

In this method, the cutting tool is positioned at an angle to the machined workpiece, allowing the machine to create curved and angled surfaces. The cutting tool moves along the surface and makes precise cuts while creating angled edges.

This is a unique and detailed method to create angled surfaces on workpieces.

3. Face Milling:

Face Milling

In the face milling method, the cutting tool is oriented perpendicular to the workpieces, similar to the plain milling process.

This process is specified for producing flat surfaces by removing the excess material from the workpiece’s surface. It is a reliable method that provides precisely shaped, large flat, surfaced products.

4. Form Milling:

Form milling is another standard method used in the CNC milling process to create complex shapes. This method uses special tools and cutters to create irregular shapes or contour the workpiece precisely. It manufactures irregular shapes, such as gears, splines, and pulleys.

Except for the above-mentioned methods, some other common types of CNC milling procedures include; pocket milling, drilling, profile milling, peripheral milling, and reaming.

How Does CNC Milling Help You Get Great Parts?

How Does CNC Milling Help You Get Great Parts

From design flexibility to efficiency, the CNC milling process is an extensive process that provides precise and consistent products.

It helps you get great parts in many different ways because it allows you to manufacture intricate geometrics which would not be possible to achieve via traditional methods.

First, it is a unique and convenient way to create complex and irregular shapes faster and less costly. It is compatible with creating angular, curved, bevel, slot, and square shape components to meet advanced industrial requirements.

CNC milling machines can be programmed with a wide material selection range.

It allows the automotive, electronics, consumer market, pharmaceutical, and medical industries to create products from different materials. Moreover, it offers consistent operation, making it capable of error-free mass production of repeated products with exact requirements.

This comprehensive process allows movements in different dimensions with multi-point cutting tools and slide and face cutters. CNC milling machine parts with high precision and accuracy at tight tolerances to meet the specifications.

CNC milling provides complete design control to the users, as you can create innovative designs without restriction. You can create intricate shapes and dimensions effectively without producing several physical prototypes.

What’s the Difference Between CNC Milling and CNC Turning?

CNC milling and CNC turning are different machining processes that utilize different tools to produce different components. Both techniques use CNC system; however, there is a distinctive difference between these two processes;

Let’s find out the major difference between these two processes:

CNC MillingCNC Turning
CNC milling uses multi-point or rotating cutting tools to cut the material from the surface of the workpiece.
Examples: End mills, drills, broachers
In this process, single-point cutting tools create conical and cylindrical surfaces by rotating the workpiece.
Examples: lathe, planer, slotter
It is an ideal process for manufacturing irregular shapes, designs, and sizes. You can produce various innovative parts with this process.Typically, CNC turning is suitable for manufacturing cylindrical and conical shapes only.
The milling machines conveniently cut material from larger surfaces with high precision.Turning machines are suited for cutting material from small and less thick surfaces, providing a smooth finish. 
CNC milling has a wide range of features. It means you can create different holes, slots, and pockets in addition to cutting the parts.The CNC turning process has a limited range of features. It is only useful for simple parts without any complexity.
CNC milling provides maximum efficiency and precision but a less smooth surface.CNC turning is less efficient than milling but provides a high-quality and smoother surface.

What Are the Applications and Uses of a CNC Milling Machine?

Over the past few years, a rapid increase in the demand for CNC milling has been observed. Are you wondering why industries are choosing CNC milling over traditional methods?

Well, the answer is simple!

Different industries choose the process because it offers efficiency, precision, and design freedom. It has become a popular choice for easy and less costly machining.

Let’s have a look at the famous industries that use CNC milling machines:

1. Automotive:


Automotive is a prominent industry that uses CNC milling widely for complex parts manufacturing, such as engine and suspension components. It is helpful for prototyping innovative automotive designs.

Automotive components require high precision and accuracy; thus, CNC milling is the right machining process for it. It creates intricate parts accurately with less lead time.

2. Aerospace:

CNC milling is popular for making different aerospace components with certain design specifications. It allows the manufacturing precise and complicated parts for engines, turbines, fuel panels, and structural components.

Aerospace parts require specific tolerance, hardness, and impact resistance; thus, they are made of specialized materials and processes.

You can create highly efficient spacecraft and aircraft parts with low lead time, ensuring the final product meets the quality and safety standards effectively.

3. Metal Fabrication:

Metal Fabrication

It is one of the core applications of CNC milling. The metal fabrication industry heavily relies on CNC milling, which is compatible with shaping different metal alloys with tight tolerance and precision.

It is a computer-controlled process, providing precisely machined alloy in less time. You can follow different methods, such as front milling, miter milling, cylindrical milling, and up-front milling, for shaping/shaving the metal sheets.

4. Agriculture:

Another common industry that uses the CNC milling process for making different parts and components is the agriculture industry. It is employed for creating farming components and large custom-made tools for irrigation systems.

The process is famous for making reliable, efficient, and long-lasting machinery and equipment for the agriculture sector. Plows, cultivators, valves, nozzles, and harvesting equipment are typical examples of components made with the CNC milling process.

5. Electronics:

Electronics is a giant sector that is rapidly growing with each passing day. CNC milling is a major process in this industry for producing precision components and parts for electronic enclosures, internal parts, and (PCB) printed circuit boards.

Its precise cuts allow the internal parts to fit perfectly in the enclosure while meeting the exact requirements of the consumers. PCBs made by CNC milling machines are useful for precise routing and port cutouts.

6. Medical:

6. Medical

CNC milling is vital in manufacturing precise and complex medical parts such as surgical instruments, medical implants, medical devices, and prosthetics.

All these components must be made with precision and accuracy; therefore, CNC milling is the right choice. Since the process offers customization, it has accelerated efficiency and favorable outcome in recent years.

7. Defense:

From military vehicles to aircraft, CNC milling is the most popular process for manufacturing various defense industry components.

It is compatible with creating different components of military weapons, communication equipment, vehicles, and aircraft. All these components are made with high precision and accurate machining to ensure they work correctly in harsh climates and disastrous conditions.

The Importance of Workpiece Holding for CNC Machining Centers:

All CNC machining processes follow different holding methods and cutting strategies to achieve an accurate outcome. CNC machining centers use several workpiece-holding methods.

It includes:

  • Clamping
  • Vacuum Suction
  • Magnetic Holding
  • Fixture Plates

Accurate workpiece holding is essential because it reduces the risk of errors and inefficiency in the finished parts.

Specifically, holding plays a significant role in manufacturing intricate parts in multi-axis machining. Proper workpiece holding prevents movements and vibration by firmly gripping the parts from various angles.

CNC Machining at Kemal | Low Volume Manufacturing & Rapid Prototyping

CNC Machining at Kemal - Low Volume Manufacturing & Rapid Prototyping

At Kemal, we are committed to providing high-quality CNC machining services with advanced equipment and proven expertise. From rapid prototyping to low-volume manufacturing, we take pride in fulfilling your projects according to your specification.

Our experienced team of professionals uses the proper machining techniques and machinery to produce high-quality and precise components for your application.

Our CNC machining capabilities include 3-axis, 4-axis, and 5-axis milling. Moreover, we offer complete customization for a wide range of materials according to customer demands.

Kemal also offers a variety of services, including Injection Molding, Mold manufacturing, and 3D Printing. For more information and an instant quote, feel free to contact us. Our customer support is available 24/7 to address your concerns.


CNC milling is versatile and flexible, so you can use various materials according to your application requirement. The materials include; metal, wood, plastic, composites, etc. 

Here are some common examples of the material:

  • Metal: Brass, Aluminum, Steel, Copper, and Titanium.
  • Plastic: PVC, PC, Silicon, Acrylic, and ABS.
  • Composite: Fiberglass and Carbon fiber
  • Wood: Hardwood and Softwood

Aluminum is best known as a lightweight and resistant metal ideal for various applications.

Some of them are as follows:

  • It is suitable for food packaging due to its anti-corrosion and high-resistance nature. Beverage and processed food packaging are common examples.
  • It is widely used in the aerospace and automotive industry to make structural parts such as body panels and wheels.
  • Due to its durability, aluminum is widely used in the construction industry for building roofs and facades.

Aluminum is a unique material due to its exceptional resistance and lightweight properties. It has been used for different industrial application for ages due to its reliable features.

However, there are several different alternatives for aluminum, but they have their benefits and drawbacks.

 Some of the alternatives that you can consider for aluminum include:

  • Steel
  • Plastic
  • Copper
  • Titanium

You may think that CNC machining and milling are the same, but it’s not true. CNC machining is a broad term that covers different computer-controlled processes. CNC machining includes CNC turning, CNC routing, CNC milling, and CNC drilling processes.

On the other hand, CNC milling is a specific type of CNC machining process that use a specific type of automated machine to shape the parts.

No, CNC milling is not an expensive process; rather, it is a cost-effective solution because it does not demand expensive machinery or high labor. It is fully automated with affordable tooling and maintenance.

However, the cost varies according to the project specification and the complexity of the produced parts.

CNC milling is a versatile and flexible process used by different industries.

Let’s talk about some common uses of CNC milling:

  • Manufacturing tooling for different processes
  • Creating prototypes
  • Making architectural models and sculptures
  • Production of medical devices, implants, and surgical tools
  • Creating complex machinery parts

The choice of the mills used in CNC milling highly depends on material properties, design complexity, and what type of product you want to build. You should always select the ideal mills for the type of manufacturing you have chosen.

But if you see widely, the following are the common mills used in manufacturing:

  • CNC Mills
  • CNC Lasers
  • CNC Plasma
  • CNC Routers
  • CNC Lathes

When we say fully automated, the process is entirely controlled by a computer numeric system that processes the design and operates the machine.

A CNC milling machine is a unique combination of CNC (Computer numeric control) software that processes the programmed design and milling cutters (single or multi-point cutters) that cut the workpiece to achieve the desired design.

It manufactures intricate parts and components from metal, glass, plastic, and wood. CNC milling provides precision, accuracy, and fast lead time for manufacturing parts for different industries.

So, whether you have low production or high-volume demands, CNC milling is the best process.

Put your parts into production today

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