What is CNC Milling? How Does It Work?

CNC milling is one of the most common operations of CNC machines. This process is used in many applications and industries and offers intricate geometries and a wide range of sophisticated features. This article elaborately explains what CNC Milling is. To learn more about CNC milling and its process and applications, you can check out the information we have below. Here are the details: Here, we will first define what CNC milling is. Then, we will explain CNC milling methods, vertical & horizontal milling, the CNC milling process, and CNC milling applications. After that, we will discuss the pros and cons of CNC milling and introduce the basic types of CNC milling machines. In the end, we will summarize what to consider when buying a CNC milling machine. 

CNC Milling: Definition

CNC milling is a combination of a milling operation and CNC technology. As you may already know, in a milling operation, different milling tools are used to remove material from a rotating workpiece to create the desired shape or feature. In classical milling, all this process is carried out and controlled by humans, and of course, is not free from human errors. On the other hand, CNC (Computer Numerical Control) technology automatically processes milling operations, eliminating human errors. The motions of milling tools are pre-programmed and controlled by a computer. The computer controls speed, tool path, cutting depth, and anything related to the milling operation. As a result, the desired shape and features on the workpiece are accurately and precisely created. CNC milling allows you to perform milling operations with minimal error and at high speeds. That is why it is widely used in many manufacturing industries. We are indebted to CNC milling for many products that we are using today.

CNC Milling Methods

Face Milling: In this method, the axis of the cutting tool is perpendicular to the surface of the workpiece. The cutting tool has multiple teeth. While one tooth cuts the workpiece, the other tooth finishes the surface. As a result, perfect finishes are created.

Plain Milling: In this method, the axis of the cutting tool is parallel to the surface of the workpiece. The aim is to create a plain horizontal surface. The cutting operation is performed along the workpiece.

Angular Milling: This method is similar to plain milling, but the cutting tool is used at different angles. There are two types of angular milling cutters: single-angle and double-angle. A single-angle cutter is used at 45 and 60 degrees, and a double-angle cutter is used at 45, 60, and 90 degrees. Features such as serrations, chamfers, or grooves are created using the angular milling method.

Form Milling: This method is used for creating irregular surfaces. The cutting tool curves the surface, and concave or convex contours are created. On the other hand, this method is 20%-30% slower compared to other methods.

Gear Cutting: In this method, the aim is to open gear teeth on the surface. Thus, herringbone, helical, spur, or worm gears are created.

Gang Milling: In this method, multiple surfaces of the workpiece are simultaneously milled using multiple cutting tools. In this way, complex contours are created. Cutting time is also reduced.

Vertical & Horizontal CNC Milling

Whereas the spindle is perpendicular to the surface of the workpiece in vertical milling, the spindle is parallel to the surface of the workpiece in horizontal milling. Factors such as machine setup, the desired shape to be created, the number of surfaces to be milled, or specific milling applications play a role in deciding which one to choose.

In general, vertical milling is easier than horizontal milling. It also produces parts less expensively. Errors can be detected and corrected more easily. It is easier to program and set up vertical milling machines, and they are user-friendly. That is why vertical milling is more popular.

On the other hand, horizontal milling permits performing the cutting operation at different angles. As a result, intricate contours can be created. Horizontal milling machines are robust and stable machines, so they produce less noise and vibrations. Eventually, we can perform the cutting operation more accurately and precisely. In brief, horizontal milling enables us to manufacture complex and detailed parts efficiently.

CNC Milling Process: A Step-by-Step Explanation

Step 1. We prepare a CAD model for our CNC machine using specific software for it. The model includes information such as tolerances, features to be created, and dimensions of cutting or finishing details.

Step 2. We convert our CAD model into a file format that our CNC milling machine can understand.

Step 3. We set up our CNC milling machine. We place the cutting tool and the workpiece.

Step 4. We start our CNC milling machine and let it do all the work. We look forward to seeing what amazing work our machine is going to produce.

Machine Components and Tools Used in the CNC Milling Process

CNC milling machines share basic components with other CNC machines. Let us have a look at the basic components of CNC milling machines:

Interface

Instructions coming from the CAD file are downloaded onto the interface to execute the cutting operation as programmed by the computer.

Column

It is the supporting point of the CNC machine. The spindle is attached to the column. It also holds the arbor.

Frame

It provides rigidity and stability. It is the house of the components of the CNC machine.

Ram

It ensures the motion along the X and Y axes by sliding back and forth. It also houses attached components like coolant or oil reservoirs.

Arbor

The milling tool is attached to the arbor. and it securely holds it. Depending on the application and process, it can be adjusted to different diameters and sizes.

Cutters

Different milling cutters are used depending on the desired shape and features to be created. Each cutter creates a different length, depth, diameter, geometry, or design.

Spindle

It holds cutting tools and provides rotating movement. It is driven by the motor and controlled by the CNC controller.

Tool holder

It is attached to the spindle to secure cutting tools. There are different types of tool holders, such as BT, BBT, or HSK.

CNC Control Panel

The milling process is controlled by the Control Panel. Data and codes are entered, and the milling process is executed.

Automatic Tool Changer (ATC)

It automates the tool changing without needing manual changing. In this way, it speeds up the milling process.

Worktable

The workpiece is placed and clamped on the worktable.

CNC Milling Applications

Concerning materials, CNC milling can be used for metals, plastics and elastomers, ceramics and composites, and glass. CNC milling perfectly shapes metals and is commonly used in metalworking. It also does a good job when applied to plastics and elastomers. In addition, it can dexterously process ceramics, composites, and glasses without harming them.

Concerning industries, CNC milling is used in almost all industries. To give an example, it creates intricate parts for the automotive industry. It provides parts with tight tolerances and high precision to the aerospace industry. It produces customized parts for the agriculture industry. It meets the demand for versatility and precision in the electronics industry. In the medical industry, CNC milling is applied to produce prostheses, implants, scalpels, and medical devices. In the defense industry, the prototypes of weapons and other defense parts are skillfully manufactured using CNC milling.

Pros and Cons of CNC Milling

We can summarize the pros of CNC milling as follows:

CNC milling accurately and precisely produces the exact part as it is designed, thereby meeting the need for tight tolerances.

The CNC milling process is fast and efficient. Thanks to its ATC tool, it can simultaneously use different cutters. The whole process is executed automatically. All these make it super-fast and efficient.

CNC milling can process a wide variety of materials such as metals, plastics, or glass.

CNC milling can easily create intricate geometries and complex shapes.

CNC milling is highly versatile and can easily adapt to different materials, processes, and applications.

We can summarize the cons of CNC milling as follows:

Too much material is removed to create the precise part, which causes wastage.

CNC milling needs continuous maintenance to keep it functioning. You may find it a bit expensive and laborious.

When you set up the CNC milling machine at the beginning, you need to design and program the milling process in detail, and it will take time and require programming skills and proficiency. Therefore, you have to work with experts and invest in sophisticated software, which can be expensive for you. However, the high efficiency provided by CNC milling will compensate for this cost in the long run.

CNC Milling Machines

We can classify milling machines by different criteria. Here is our classification of CNC milling machines.

a. Classification by Milling Cutter

b. Classification by Application

c. Classification by Direction

d. Classification by Structure

Depending on the nature of your cutting operations, needs, and budget, you will select one of these CNC milling machines. You should think carefully before making your selection.

What to Consider When Investing in Milling Machines

The first thing to consider is the size of the parts you intend to produce. You have to select the correct CNC machine appropriate for the size of the product, whether you are going to produce small, medium-sized, or large parts.

Then, you need to make a selection between vertical and horizontal milling machines. If your production does not require complex cutting, you can opt for inexpensive vertical milling machines.

The material to be removed is also important. Accordingly, you should choose milling cutters.

Different features that you desire to create will also play a role in your choice.

Considering all these, decide on the most suitable CNC milling machine for you. Then, most importantly, you must find an expert manufacturing company for these machines. Working with a reputable manufacturing company that can provide quality machines and a reliable after-sales service is highly important.

Conclusion

We believe that we have painted a picture of what CNC milling is. Maybe you have already decided what kind of CNC milling machine you must invest in. With years of experience, excellent quality, and a wide variety of CNC milling machines and complete after-sales services, your dream machine can be one of our CNC milling machines. Just contact us to experience the privilege of working with us.