4-Axis CNC Machining: A Comprehensive Guide

What Is 4-Axis CNC Machining?

4-Axis CNC machining involves multi-axis machining of workpiece material with CNC machines with an extra rotary axis. The 4-axis machining process utilizes any CNC machine that can simultaneously move at four different angles. It usually comprises the three linear axes – X, Y, and Z and an additional axis (A-axis). The X, Y, and Z axes denote the three mutually perpendicular directions, while the A-axis rotational axis rotates the workpiece around the X-axis.

Although 4-axis CNC machines are available in different arrangements, the standard type is vertical machining. It operates in the vertical direction, allowing the spindle’s movement to be in the Z-axis. More so, these properties will enable the machining of complex designs and milling at odd angles, which 3-axis machining cannot achieve.

The Process of 4-Axis CNC Machining

The movements and capabilities of CNC machines help better understand the 4-axis CNC machining process. 4-axis CNC machines work smoothly by allowing the machine tool to move along the X, Y, and Z axes while rotating the workpiece on the A axis concurrently. The added axis permits the tool to machine the workpiece from different angles, creating complex parts with tight tolerances.

Steps in Involved 4-Axis CNC Machining                     

• Step 1 (CAD Design): A product design is critical to any machining project. You can draft a design CAD design with Computer-Aided Design software. You can use various software to create a CAD design for your intended CNC part.
• Step 2 (CAM Path): After the design is ready, the CAM (Computer-Aided Manufacturing) software provides a toolpath that guides the direction of the CNC machine’s cutting tool.
• Step 3 (Setup): Here, you have to mount the blank or workpiece material on the CNC machine and set up the appropriate cutting tools on the machine.
• Step 4 (Machining): The 4-axis CNC machine enables continuous machining at different angles by rotating the mounted workpiece on the A-axis while the cutting tool approaches the workpiece in the X, Y, and Z directions.
• Step 5 (Finishing): Upon completion of the machining process, any required post-processing operations like cleaning, deburring, or surface finishing will occur.Advantages of 4-Axis CNC machining

4-Axis machining offers an extensive range of advantages for various manufacturing industries. Below are the expected benefits of 4-axis CNC machining:

Versatility

4-axis CNC machining is a versatile process for machining different components ranging from small electronic parts to large aerospace machined parts. They are also suitable for handling various CNC machining materials and part sizes. Hence, 4-axis CNC machines are valuable to any manufacturing setup.

Improved Capabilities

The extra axis in the 4-axis CNC machines helps manufacturers across industries create more complex parts with intricate design specifications. As a result, it presents new possibilities in manufacturing CNC machined parts that would have been otherwise difficult with three axes.

Higher Precision

The 4-axis CNC machines offer better control over machining operations due to the additional rotary axis. As a result, you can efficiently machine CNC parts with the preferred accuracy and precision to meet strict quality standards.

Optimized Efficiency

4-axis CNC machining facilitates continuous machining from different angles without manually repositioning and realigning the workpiece. Hence, it reduces the overall time for producing CNC parts.  

Limitations of 4-Axis CNC Machining

Although 4-axis CNC machining offers remarkable benefits, the process has certain limitations. Here are some of them:

Costly Setup

Purchasing and setting up 4-axis CNC machines can be too expensive, making it a significant investment for any business. However, the investment may recompense in the long run, considering the 4-axis CNC machine’s efficiency and capabilities.

Geometric Limitations

Despite the additional A-axis, 4-axis CNC machines encounter setbacks in machining certain geometries and angles. As a result, it would help to use a 5-axis CNC machine in such situations.

Requires Trained Experts

Even though 4-axis CNC machining is a computer-controlled process, a skilled operator needs to set up, program, and supervise the whole operation. Therefore, it increases the cost of operation.

Common Types of 4-Axis CNC Machines

There are different types of 4-axis CNC machines that product teams utilize in machining CNC parts. Each of these machines possesses unique capabilities that make it ideal for respective applications:

Lathes

4-axis CNC lathes are versatile and suitable for turning operations. The lathe’s additional axis enables the tool to approach the workpiece from any angle, creating complex geometric designs. A 4-axis CNC lathe can fabricate extensive materials, including wood, plastics, and metals. As such, it provides a broad range of possibilities for the manufacturing industries.

Milling Machines

Milling Machines are the most widely used 4-axis CNC machines. These 4-axis CNC machines are well-suited for fabricating intricate features such as angled cuts and holes in complex parts. The additional A-axis on the CNC milling machines enables the cutting tool to machine the workpiece at an angle, creating holes and mill slots at any preferred angle.

Routers

4-axis CNC routers are commonly found in the woodworking industry. They offer high precision and can effectively work on large parts. These CNC routers remain indispensable in any production line due to their robust construction and simple setup.

Typical Industries Using 4-Axis CNC Machines

4-axis CNC machines have versatile applications since they can effectively handle several complex design requirements. Below are some of the common industries that use 4-axis CNC machines:

• Automotive
• Medical Sector
• Aviation and aerospace
• Oil and Gas
• Electronics
• Construction

Comparison Between 3-Axis, 4-Axis, and 5-Axis Machining

Although the number of axes represents a fundamental comparison between 3-, 4-, and 5-axis CNC machining. Below are further differences:

Flexibility

Amongst all three machining processes, 3-axis CNC machining is the most basic and widely used form. It offers the least flexibility. The movement of the machine is only along three axes (X, Y, and Z). One (Z-axis) represents the spindle movement up and down, X-axis represents left and right movement, and Y-axis denotes forward and backward movement. It is best used for machining simple CNC parts with flat or slightly curved surfaces.

4-axis CNC machining combines a rotational A- or B-axis to the three linear axes –X, Y, and Z. As a result, 4-axis CNC machining is ideal for machining parts at different angles with features like groves, undercuts, and curves.

For maximum flexibility in CNC machining operations, the 5-axis is the go-to choice. Its additional two rotational axes (A and C) make it suitable for machining complex CNC parts with intricate geometries and deep undercuts.

Rotation in Axes

3-axis machining has restricted rotational capability since the machine tool’s movement occurs linearly along the X, Y, and Z axes. Hence, it is difficult to machine hard-to-reach aspects of a workpiece since the cutting tool maintains a uniform position. On the other hand, 4-axis CNC machining allows the workpiece’s rotation with the additional rotary A- or B-axis while the cutting tool follows the linear axes.

However, 5-axis CNC machining has two added rotary axis (A and C), which facilitates the cutting tool’s optimized control over how it engages the workpiece to make complex parts. Here, the cutting tool and the spindle move along three axes while other rotations occur on two of the three axes (A-, B-, and C-axis), depending on the configuration.

Cost

The most cost-effective of the three machining processes is 3-axis CNC machining. It offers cheaper machine, tooling, and setup costs. 4-axis CNC machining costs slightly higher than 3-axis machining because of the added rotary axis. However, it maintains an impressive balance between machining capability and cost.

In contrast, 5-axis machining is the most costly option because of the machine’s features and capability for simultaneous machining along 5 axes. It also doesn’t require multiple setups, offering optimized accuracy and efficiency. Hence, it is ideal for high-end applications demanding high precision and complex geometries.

Conclusion

4-Axis CNC machining is an advanced process that ensures optimized efficiency, precision, and versatility. Although there are some setbacks to the process, it provides higher capabilities in machining more complex features in complex parts. However, it is essential to understand everything about this process to know how best it matches your project!

AT-Machining is a reliable CNC machining service provider with an extensive range of high-precision precision machining equipment. Our expert machinists and engineers leverage our state-of-the-art 3-, 4-, and 5-axis CNC machines to manufacture your CNC parts within the preferred tight tolerances. Contact us today to learn more about how we can assist you in making your next product design stand out in today’s market.