5-axis CNC machining is a multi-axis subtractive manufacturing process that involves the tool moving in five directions or axes (X, Y, Z, A and B). The five axes move in coordination, enabling the machine to perform high-precision machining on five different sides of the workpiece in a single clamping without repositioning the workpiece between operations. This multi-axis linkage capability makes it possible to machine complex geometries, especially suitable for parts with high requirements for spatial structures and free-form surfaces.
CNC axis count refers to the number of directions a CNC machine can move to produce the desired part. Take a traditional three-axis CNC machine as an example. It naturally has three axes. A three-axis machine can move horizontally on the X axis, up and down on the Y axis, and forward and backward on the Z axis.
In addition to the three linear axes, a 5-axis CNC machine adds two axes, commonly referred to as the A axis and the B axis. These two additional axes enable a 5-axis machine to tilt and rotate the cutting device or part to produce more complex geometries than a 3-axis machine. Therefore, this additional axis enhances the type of work the machine can undertake and the level of detail it can cut.
These make 5-axis machines the secret to producing high-precision parts without seams or weld marks. 5-axis machining capabilities have changed manufacturing industries such as automotive, healthcare, aerospace and agriculture.
The difference between 5-axis machining and 3+2-axis machining
Although both 5-axis machining and 3+2-axis machining are multi-axis machining technologies and can be used for high-precision manufacturing of complex parts, they are essentially different in terms of machining methods, flexibility, efficiency and equipment structure.
- Five-axis machining method
Five-axis machining: All five axes (X, Y, Z + A, B or C) can run simultaneously in linkage, and the tool can dynamically change the angle and path during the machining process to continuously cut complex surfaces or polyhedrons.
3+2-axis machining: It is essentially three-axis linkage + two-axis positioning. That is, before the machining starts, the workpiece or tool is positioned to a specific angle through two rotary axes (A/B or B/C), and then three axes (X/Y/Z) are used for conventional cutting. The rotary axis does not participate in the linkage motion during the cutting process.
- Processing flexibility
Five-axis machining: The machining flexibility is extremely high, and the tool can approach the workpiece from almost any angle, reducing dead angles and interference, and greatly optimizing the machining path.
3+2 axis machining: The flexibility is not as good as continuous five-axis, and the machining path is limited by the tool direction and positioning angle.
- Machining efficiency and speed
Efficiency and speed are the main advantages of 5-axis machining compared to 3+2 axis CNC machining. The speed difference is that 3+2 axis machining requires continuous machine tool stopping and starting to achieve the best tool direction. 5-axis CNC machining does not require downtime because only one operation is required for machining.
Types of five-axis CNC machine tools
The type and structural configuration of CNC machine tools (such as vertical, horizontal, double swing head, etc.) will directly affect its machining speed, tool path flexibility and final machining quality. Therefore, the rational selection of suitable five-axis CNC equipment is a key step in efficient and precision manufacturing.
Five-axis CNC machine tools can provide different types according to the needs of the manufacturing industry, and the main difference lies in the setting of the rotation axis. According to the type of rotating axis, five-axis linkage CNC machine tools can be divided into three categories: double pivot table five-axis, double pivot head five-axis, single pivot table single pivot head five-axis.
- Double pivot head
The double pivot head of a five-axis machining center refers to the two rotating axes on the machining center, usually the A axis and the C axis. The workpiece is fixed, the tool moves around the workpiece in five dimensions, and the 5-axis vertex platform enables it to perform tasks. The worry of tool interference on the machine tool spindle head is eliminated. The fixed worktable allows the 5-axis vertex to move around the workpiece, which is very suitable for manufacturing large parts. Their design allows for minimal movement of the axis.
The existence of a double pivot head can give the machining center greater machining freedom. By rotating the A axis and the C axis, multiple angles of the workpiece can be machined, thereby achieving more complex part machining.
- Double Rotary Table
Both rotating axes of this technology belong to the rotary table category, the B axis rotation plane is the YZ plane, and the C axis rotation plane is the XY plane. Generally, two rotating axes are combined into a whole to form a double turntable structure, which is placed on the worktable.
The two rotating coordinates directly control the rotation of the space. During the processing, the worktable rotates and swings. The size of the workpiece that can be processed is limited by the size of the turntable, and the working range is narrow and the speed is slow. Therefore, the double turntable five-axis is suitable for processing small and light workpieces, such as small integral turbines, small precision molds, etc. In addition, the spindle is always in the vertical direction, the rigidity is relatively good, and a large amount of cutting can be processed.
- Rotary Table and Pivoting Spindle Head
Two rotating coordinates, one acting on the tool and the other on the workpiece. During the processing, the worktable only rotates and does not swing, and the spindle only swings in one rotation plane. The processing characteristics are between the double turntable and the double swing head. Compared with the double swing head, one advantage of this setting is that there is no need to worry about reaching a specific limit because the part is always rotating. In contrast, because the part or workpiece is located on the rotating axis, the design of the CNC machine tool limits the number of products it can produce.
Typical parts commonly processed by five-axis machining centers
Five-axis CNC machine tools can achieve highly automated processing with almost no human intervention. It uses rotating tools to perform high-precision cutting and forming of materials fixed on the worktable.
However, clamping the material to the machine tool worktable is only the last step in the entire 5-axis machining process. Before that, the part needs to be designed in CAD and converted to CAM. Then a program in G-code format is generated to transmit the instructions directly to the CNC machine tool.
G code is crucial in the entire machining process. It contains detailed instructions such as tool path, machining sequence, tool selection, feed speed, cutting depth, etc., guiding the machine tool to complete accurate and efficient machining tasks.
In terms of precision engineering technology, five-axis machining can provide the best precision engineering solutions:
- Complex curved surface parts
Complex curved surface parts are often seen in different fields such as aerospace, electronics, and automobiles. It is difficult to achieve such complex surfaces using ordinary CNC machine tools. Common complex surfaces that can be produced by five-axis machining include spheres, turbine engine blades, marine propellers, impellers, underwater vehicle propellers, and some other free combination surfaces. The programming workload of using a five-axis machining center to process complex surface type parts is relatively large, and automatic programming technology is used to program complex surface type parts.
- Disc parts
5-axis CNC machining is also an ideal choice for processing drone parts. It is suitable for processing plate parts and plates, especially parts and plates with end face distribution holes or radial holes. It is also suitable for making machine motor covers. It should be noted that the application of 5-axis CNC machining to such parts requires the use of a horizontal machining center or a vertical machining center. The selected machining center depends on the specific hole direction.
- Box parts
Five-axis machining is suitable for the processing of various box parts with strict machining accuracy requirements. Since most of the parts in the box are engraved with various holes or patterns on the plane, they are generally processed through multiple processes such as milling, drilling, expansion, boring, twisting, and tapping. Various types of tools are required, and more tools are used. Due to the large number of steps and operating tools used, the use of a five-axis machining center can suddenly become more superior and refined.
Due to the need for multiple clamping and alignment, it is relatively difficult to process box parts using ordinary machining tools, and the machining accuracy is difficult to guarantee. The 5-axis machine is able to work on multiple surfaces at the same time, which makes it easier to produce higher-precision box parts.
- Special-shaped parts
Special-shaped parts refer to parts with irregular shapes. For example, workpieces with multiple stations of points, surfaces, and lines. Since the clamping pressure is difficult to control during machining, and the rigidity of special-shaped parts is generally poor, it is difficult or almost impossible to process such parts using traditional machining methods. However, the operation of a five-axis machining center can simultaneously integrate the machining of different points, lines, surfaces, and multiple stations, making it easier to complete multiple processes.
Summary
The five-axis machining center not only represents the mature application of high-level CNC technology, but also provides a realistic solution for efficient, one-time molding of difficult parts. Five-axis CNC machining helps to produce complex parts with high-quality surface finish. Although the initial cost is high, this machining method helps save time and money in the long run.
Whether in the aerospace, medical device or automotive manufacturing industries, five-axis machining is constantly expanding its application boundaries. For manufacturing companies, a deep understanding of the process characteristics and equipment capabilities of five-axis machining centers is a key step in improving competitiveness and achieving high-quality manufacturing.
