CNC machining is a technology that uses computer-controlled machine tools to process parts. In the field of CNC machining, we often hear terms such as 3-axis, 4-axis, and 5-axis CNC machining, which describe the complexity of machining centers and the range of geometric shapes they can handle.
So, what is the difference between 3-axis, 4-axis, and 5-axis? What are the advantages? What products are suitable for processing? Please continue reading for more relevant information.
3-Axis CNC Machining Overview
3-axis CNC machining is the simplest CNC machining method. In 3-axis machining, the workpiece remains fixed and the rotating tool moves along X Y. Z moves along three axes, such as up and down, front and back, and left and right.
Three axes can only process one face at a time, which is a limitation for many parts that require machining holes or grooves on multiple faces.
Compared to 4-axis and 5-axis machining centers, 3-axis machining is suitable for processing simple flat and three-dimensional shapes, such as 2D and 2.5D pattern carving, slot and surface milling, threaded holes aligned with machine axes, drilling, etc.
Advantages and Disadvantages of 3-Axis Machining
From a cost perspective, 3-axis CNC machines have a significant price advantage compared to higher-axis alternatives. Small and medium-sized enterprises (SMEs) and startups can obtain efficient and reliable machining equipment within a limited budget. Moreover, 3-axis machining, with its relatively simple user interface and control logic, allows CNC machine operators to get started without extensive, complex training. The programming required for 3-axis CNC is straightforward, enabling production personnel to quickly modify programs as needed to make changes to parts. Due to the simple structure of the machine, maintenance costs for 3-axis CNC machines are also relatively low.
However, there are some limitations to 3-axis CNC machining technology. Although the speed of 3-axis CNC machining is an improvement over traditional manufacturing methods, it is significantly slower compared to high-axis CNC machining. With only three axes for motion control, 3-axis CNC machines encounter difficulties when manufacturing parts with complex geometries. A 3-axis CNC machine can only machine one side of a part during a single setup, often necessitating frequent readjustments of the part throughout the production process. This not only reduces production speed but can also increase the scrap rate of parts.
4-Axis CNC Machining Overview
4-axis machining is more advanced than 3-axis machining. 4-axis CNC machining involves adding an x-axis rotation (also known as the a-axis) to the 3-axis, which can rotate 360 ° horizontally. In addition to the movement of the tool on the XYZ plane, it also allows the workpiece to rotate on the Z-axis. This means that 4-axis machining can work on up to 4 faces without the need for any fabricated fixtures or cutting tools.
4-axis CNC machining is suitable for machining polyhedral parts, spiral lines with rotation angles (such as cylindrical oil grooves), spiral grooves, cylindrical camshafts, cycloids, etc. If you need to drill holes on the side of a part or on the surface of a cylinder, 4-axis CNC machining is the best choice.
Advantages and Disadvantages of 4-Axis Machining
4-axis CNC machining has significant advantages in multi-sided machining and mass production. 4-axis CNC machines can process four sides of a workpiece, eliminating the need for multiple setups. This results in lower overall costs for high-volume production. Compared to 3-axis CNC machines, 4-axis machines are more competitive in high-volume manufacturing. Additionally, 4-axis CNC machining can achieve tighter tolerance requirements, which is crucial for industries that require high-precision parts, such as aerospace and automotive manufacturing.
However, there are also some drawbacks to 4-axis CNC machining technology. The machine cost of 4-axis CNC machines is relatively high, exceeding that of 3-axis alternatives. This can increase the initial investment cost for a company. The fixtures required for 4-axis CNC machines are also relatively expensive. For workpieces that only need single-sided machining, using fixtures for 4-axis machines may not be economically viable. Therefore, when deciding whether to use a 4-axis machine, it is important to weigh the specific machining needs.
5-Axis CNC Machining Overview
5-axis machining is performed in 3-axis linear motion (X Y. On the basis of the Z-axis, two rotation axes (A) have been added The motion of the B-axis. This multi axis rotation and the ability of the tool to move in three directions are two essential qualities that enable these machines to handle the most complex tasks.
There are two types of 5 axis CNC machining on the market. 3+2-axis machining and continuous 5-axis machining. Both operate on all planes, but the former has the same limitations and working principle as the indexing 4-axis machine.
3+2-axis CNC machining allows rotation to be independent of each other but restricts the use of two coordinate planes simultaneously. On the contrary, there is no such limitation for continuous 5-axis machining. Thus achieving excellent control and being able to easily process the most complex geometric shapes.
Advantages and Disadvantages of 5-Axis Machining
5-axis CNC machines offer unprecedented possibilities for machining complex parts. With their unique 5-axis motion control, they can produce intricate shapes and perform continuous milling operations, thereby speeding up production and enhancing efficiency. Because the cutting tools can move along five axes, they can create smoother surfaces and more precise parts. Another notable advantage is that 5-axis CNC machines do not require frequent tool changes. Whether dealing with simple geometries or complex surfaces, 5-axis equipment is capable of producing a wide variety of parts.
However, despite the many advantages of 5-axis CNC machines, there are some significant drawbacks. Compared to 3-axis CNC machines, 5-axis machines are much more expensive, making them less affordable for small enterprises. The operation and maintenance of 5-axis CNC machines require more specialized training and expertise. Due to their complexity, operators need to possess certain skills and experience to fully leverage their advantages. Additionally, regular maintenance and servicing are essential to ensure these complex machines run smoothly and to prevent malfunctions.
Differences Between 3-Axis, 4-Axis, and 5-Axis CNC Machining
Understanding the complexity and limitations of CNC machining is essential to ensure the optimal balance between process cost, time, and quality.
Here are 5 main differences between 3, 4, and 5-axis CNC machining.
Differences in axes
The 3-axis machining machine has X Y. The three straight axes of Z together control the linear movement of the tool in three-dimensional space. On the other hand, 4-axis machining adds a rotation axis (usually the A or B axis) on top of the 3-axis, allowing the tool or workpiece to rotate around a fixed point. 5-axis machining goes further by adding two rotation axes (usually A and B axes or A and C axes) on top of the 3-axis, allowing the tool to process in any direction. By increasing the number of axes, the machining equipment can operate the workpiece with more degrees of freedom, thus achieving more complex machining tasks.
Summary: The number of axes and range of motion for 3, 4, and 5 axis machining:
- 3 axes with X Y. Z-axis
- 4 axes with X Y. Z and A-axis
- 5 axes with X Y. Z, B, and C axes
Cost
The purchase and maintenance costs of 3-axis CNC machine tools are relatively low. However, due to the potential need for multiple clamping and positioning, additional fixtures and customization may be required for complex workpieces, thereby increasing overall costs.
On the other hand, 4-axis and 5-axis machining technologies are more advanced and have better performance. Therefore, their prices are naturally higher. But they allow for multi plane machining on a single fixture, reducing clamping costs and improving machining accuracy.
Precision and accuracy
Although 3-axis CNC machining is precise, it may accumulate dimensional errors due to the need for repeated clamping of the workpiece. For most applications, this error is acceptable, but for sensitive applications such as aerospace and automotive manufacturing, higher accuracy may be required.
4-axis and 5-axis CNC machining do not require repeated clamping and can process multiple planes on a single fixture, reducing accumulated dimensional errors and providing higher accuracy and precision.
If there is no need to re clamp. So, theoretically, the overall quality in terms of accuracy and precision is consistent between the 3-axis, 4-axis, and 5-axis.
Delivery time
As for a single machining center, a 5-axis CNC machining center has the fastest speed when processing complex shapes because it can approach the workpiece from multiple angles, reducing downtime.
4-axis machining centers are secondary because they allow rotation on one axis and can only process planar angle features at once.
3-axis CNC machining centers typically require processing in multiple stages, so delivery times may be longer. However, in practice, high overall efficiency can be achieved through parallel processing of multiple 3-axis machine tools.
Application scope
Due to its simplicity and stability, 3-axis CNC machining is commonly used to manufacture simple parts, such as flat panels and simple three-dimensional structures.
4-axis and 5-axis CNC machining can process more complex surfaces and three-dimensional shapes, suitable for machining scenarios that require high precision and surface quality, such as medical devices, aerospace and other fields.
Which is Better, 3-Axis vs 4-Axis vs 5-Axis Machining?
In the manufacturing industry, there is no absolutely better method or one size fits all solution. The correct choice depends on the complexity of the project, overall budget, time, and quality requirements.
3-axis vs 4-axis vs 5-axis, each with its own advantages and disadvantages. Naturally, 5-axis can create more complex 3D geometric shapes, while 3-axis can quickly and consistently produce simpler works.
is no answer to the question of which is the better choice. Any processing method that can achieve a perfect balance between cost, time, and results is an ideal choice for a specific project.
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FAQ
CNC machining has advantages such as high precision, high efficiency, and high degree of automation, which can ensure machining quality, improve production efficiency, and reduce labor costs.
Catalog: CNC Machining Guide
This article was written by engineers from the BOYI team. Fuquan Chen is a professional engineer and technical expert with 20 years of experience in rapid prototyping, mold manufacturing, and plastic injection molding.
