CNC Milling: Its Definition, machines, and operations

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What is CNC milling, and how does this subtractive manufacturing process work?

The speed and accuracy of milling machines have significantly increased over the years, making them indispensable tools in many industries.

This article explains everything you need to know about CNC milling before choosing it for your project; we will take a closer look at milling, different types of milling machines, and some operations that can be performed with them. Let’s get started!

What Is CNC Milling?

CNC milling is a machining process that uses computer numerical control to guide the movements of a cutting tool. This process can be used to create highly precise parts with complex geometry. 

To create a part, a three-dimensional model is created in computer-aided design (CAD) software. This model is then converted into instructions for the CNC machine, which controls the movement of the cutting tool. 

The process can be performed on various materials, including metals, plastics, and composites. 

CNC milling is often used in the aerospace and automotive industries, where components with tight tolerances are required. 

Generally, milling is most appropriate as a secondary or finishing process for a workpiece that has already been machined, providing sharpness to or fabricating the part’s characteristics, like openings, grooves, and threads.

Types Of CNC Milling Machines

Vertical Milling machines

A vertical mill is a milling machine designed to remove material from a workpiece by feeding the workpiece against a rotating cutter. The cutter is mounted on a spindle aligned with the workpiece’s axis, and the workpiece is fed into the cutter at a right angle. 

The cutting tools are held in place by a chuck that can be rotated to different positions, and an electric motor powers them. Vertical mills are used extensively in the machining of metal parts. 

Turret Vertical Mill

Bed vertical mills are specialized CNC milling machines designed for larger workpieces. These machines typically have a large table that can accommodate workpieces of various sizes.

Bed Vertical Mill

Turret vertical milling machines have their spindles oriented vertically, giving them a smaller footprint and more rigid.

Horizontal Milling machine

A horizontal mill is a machine tool that removes material from a workpiece by feeding it past a rotating cutter or multiple cutters. The cutter(s) are mounted on a spindle that can be cycled at high speeds, and the workpiece is fed into the moving table of the milling machine. 

Horizontal mills are typically used to perform end milling, face milling, and slotting operations. They can also be used to create grooves, pockets, and threads.

Knee Mill

A knee mill is a type of vertical milling machine where the spindle is equipped with a knee that sits on and moves along a horizontal track. The knee scans the work area, providing motion in the X- and Y-axes. A knee mill may also have a Z-axis, which provides motion along the Z-axis. 

Knee mills are generally more precise than other milling machines and are also more expensive. Consequently, they are typically used for more delicate or intricate work.

Multi-Axis Mill

2-axis cnc milling machines

A 2-axis milling machine is a machine that can move a workpiece in two directions–X and Y axes. 

The X-axis is horizontal, and the Y-axis is vertical. The workpiece is clamped to the milling machine’s table and fed into the spinning cutter. The cutter removes material from the workpiece by moving along the X and Y axes. 

2-axis milling machines are typically used to create flat surfaces, slots, pockets, and dies. 

3-axis cnc milling machines

3-axis milling machines are computer-controlled machines that can move a workpiece in three directions. The X-axis is the horizontal direction, the Y-axis is the vertical direction, and the Z-axis is the depth. 

These machines can cut complex shapes out of metal or other materials. 3-axis milling machines are extremely precise and can create parts with tight tolerances.

4-axis cnc milling machines

A 4-axis milling machine is a type of CNC milling machine. Unlike most milling machines with three axes of movement (x, y, and z), a 4-axis machine has an additional axis (a fourth), allowing for more complex milling operations.

With a 4-axis machine, it is possible to mill beveled edges or contoured surfaces that would otherwise be difficult or impossible to create with a 3-axis machine.

5-axis cnc milling machines

Unlike traditional milling machines, which are limited to three axes of motion, 5-axis milling machines allow for greater control and flexibility, allowing operators to produce more intricate shapes and designs. In addition, 5-axis milling machines are equipped with more powerful motors and cutting tools, making them capable of handling tougher materials.

Types Of CNC Milling Operations

Face Milling

Face milling is a machining process in which a rotating cutter removes material from the surface of a workpiece. The face milling cutter is a circular cutting tool with multiple teeth on its periphery. 

The cutting tool can be horizontal or vertical, and the workpiece can be moved in a linear or rotary motion. Face milling is used to produce flat surfaces, and the depth of the cut is typically limited to half the diameter of the cutter.

When face milling with a CNC machine, the cutting tool is mounted on a spindle and does not move during the machining operation. The workpiece is mounted on a table and is moved in a linear or circular motion under the cutting tool.

Plain Milling

Plain milling is a milling operation in which the cutter rotates about a horizontal axis, and the workpiece is moved parallel to the axis of rotation. This type of milling is used to produce flat surfaces on workpieces with irregular shapes. Plain milling can also produce angular surfaces if the workpiece is tilted at an angle…

Angular Milling

Angular milling is a type of CNC milling operation. In angular milling, the cutter is rotated at an angle to the workpiece. This angle can be anything from 0 degrees to 90 degrees. 

Angular milling is used to create angular cuts, pockets, and tapers. It is also used for drilling and reaming holes. 

When using angular milling, keeping the cutter aligned with the workpiece is vital. Otherwise, the cutter could damage the workpiece or cause it to malfunction.

Form Milling

Form milling is the process of unique machining contours composed of angles, curves, and tapers. It specializes in cutting irregular or curved shapes into metal, plastic, or other materials. The cutter used for form milling is a circular cutting tool with teeth on the periphery and sides. 

Straddle Milling

Straddle milling is when the cutter straddles the workpiece, cutting both above and below it. This can be done with two separate cutters or a single cutter with two cutting edges. 

Straddle milling is often used to rough out large volumes of material quickly and produce slots or other features that require cuts on both sides of the workpiece.

Gang Milling

In a gang milling set-up, multiple cutters are mounted on the same arbor. This enables the machinist to mill several features into a part simultaneously. 

When using gang milling, it is crucial to consider the cutting tools, feeds, and speeds. Using the wrong tools or operating at the wrong speeds can damage the workpiece or cause tool breakage.

Benefits Of CNC Milling

Unlike traditional milling machines, CNC machines can be programmed to perform various operations, making them ideal for complex tasks. 

CNC milling machines can achieve high levels of precision, making them ideal for creating small parts and components. 

There are numerous benefits to using CNC milling machines, including increased efficiency, improved accuracy, and reduced production costs.

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CNC Turning: Its Definition, Machines, And Operations

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Machining Capability

Our team has the experience and skills to help you produce your product with CNC milling. We are proficient in using this method and can help ensure that your product is high quality and precisely what you are looking for. If you are interested in learning more about our services or want a quote, don’t hesitate to contact us today. We would be happy to discuss your project with you and answer any questions you may have.


Suppose you are now looking for a machine that can do a specific job or want to learn more about the different machines and operations available with CNC Milling. In that case, we urge you to visit our homepage—with so many options and capabilities, knowing what questions to ask before purchasing is essential. We hope this article has helped equip you with the knowledge necessary to make an informed decision when investing in CNC milling technology.


What is the CNC milling process?

CNC milling is a machining process that uses computer numerical control (CNC) machines to create parts and components from raw materials. The CNC machine uses a rotating spindle with cutting tools that move in three axes to shape the material. It can also be used for drilling, tapping, countersinking, and other operations. The CNC milling process begins with creating a digital model on a computer-aided design (CAD) program. This model is then converted into commands for the CNC machine to execute. During the CNC milling process, the spindle removes material from the part until it reaches its desired shape and size. The operations are highly precise, and the finished product contains a replica of the design from the CAD program. CNC milling offers many advantages over conventional machining processes, including greater accuracy, faster production times, and improved safety.

How Much Does CNC Milling Cost?

CNC milling is a popular manufacturing process to create complex parts and components precisely. CNC milling costs vary according to the size, complexity, and number of parts produced. Generally, the more complex the part or component, the higher the cost. For small-scale projects that require few parts and minimal complexity, the cost of CNC milling can range from hundreds to thousands of dollars. However, for larger projects that require multiple components and greater complexity, the cost can be much higher—upwards of tens of thousands of dollars in some cases. In addition to material costs, other factors such as labor costs, machining time, and setup time should be considered when estimating CNC milling costs.

What are CNC milling parts?

CNC Milling Parts are precision components machined from various materials such as metals, plastics, and composites. These parts typically feature intricate shapes and tight tolerances, making them difficult to produce with traditional manufacturing techniques. CNC Milling Parts are ideal for applications that require accuracy and repeatability, such as computer numerical control (CNC) machinery and robotic systems. With the help of advanced computer software, complex shapes can be designed quickly and accurately while controlling the speed, feed rate, and tool path to ensure precise final dimensions. CNC Milling Parts have become widely used in many industries due to their ability to quickly produce complex designs without sacrificing quality or tolerances. They are also cost-effective solutions for high-volume production runs.

What is CNC Turning?

CNC Turning is a machining process used to create a variety of parts and components with high precision. It uses a CNC machine programmed to rotate a workpiece while cutting tools are used to shape it. The outcome of the CNC Turning process is an extremely precise part or component that can be used in many different applications. It is most commonly used to create parts requiring complex shapes, such as those in the aerospace and automotive industries. Aside from producing accurate parts and components, CNC Turning also allows for faster production times than traditional machining processes. Additionally, it can produce higher-quality finishes and parts with intricate details due to its ability to control the cutting speed precisely and the depth of the tooling.