What is 5 axis CNC machining? Process, applications, pros, and limitations

5 axis CNC machining is a versatile and advanced manufacturing process that is applied in numerous industries due to its ability to produce complex geometries and precise parts fast. This machining method enables the cutting tool and workpiece to move in five different axes, creating complex geometries with high precision and superior surface finishes.

In this article, learn how 5 axis CNC machining works and its applications, benefits, and limitations. 

What is 5 axis CNC machining?

5 axis CNC machining is a machining setup in which the workpiece and cutting tool can move in five axes. In CNC machining, a cutting tool selectively removes portions of a block of material until the desired object forms. During this process, the machine head and worktable move the cutting tool and workpiece, respectively, to give the cutting tool access to different areas of the workpiece. The direction and orientation of these movements constitute the machining axes. The image below shows a form of 5 axis CNC machining.

As the name implies, 5-axis CNC machining covers five machining axes, three linear and two rotational. The linear axes are the X-axis (left to right movement), Y-axis (forward and backward movement), and Z-axis (up and down movement). Depending on the machine, the two rotational axes are any two out of the A-axis (rotation along axis X), B-axis (rotation along axis Y), and C-axis (rotation along axis Z). For example, a specific 5-axis CNC machine may be capable of movement in the X, Y, Z, A, and B axes, while another machine can move in the X, Y, Z, B, and C axes. The axes described are in the image below.

5 axis CNC machining is a step up from the more conventional three-axis machining in which the workpiece and the cutting tool move in three linear axes. This advanced machining process is faster and more capable than 3 to 4-axis machining. However, it is also more complex, requiring more advanced tool path programming. In addition, it can be twice the cost of 3-axis milling due to the cost of the machine and the complexity of the process.

Types of 5 axis CNC machining techniques and machines

Different types of 5 axis CNC machining techniques and machines exist. These machines can be classified according to the timing of the movements and the machining operations. The types of 5 axis CNC machines, according to this category, are:

• Indexed 5 axis CNC milling
• Continuous 5 axis CNC milling
• 5 axis CNC mill-turning centres

Indexed 5 axis CNC machining

Also known as 3+2-axis machining, the key distinguishing characteristic of indexed 5 axis CNC machining is that the movement is not continuous in all five axes. During machining, the machine continuously cuts in the three linear axes. These movements are part of the cutting operation. On the other hand, the two rotational movements serve to reposition the cutting tool or workpiece. The cutting process stops temporarily during rotation.

In summary, cutting proceeds on three linear axes. When necessary, cutting stops, and the machine repositions the cutting tool or workpiece, rotating by a specific angle. Cutting then resumes along the three linear axes in the new position. These steps occur rapidly and continue intermittently till the part forms. In most indexed 5 axis CNC machine configurations, the table provides the rotational motion, typically in the A and C axes, while the cutting head executes the linear motions. Indexed 5 axis machining is less expensive than its continuous counterpart but 65% more costly than conventional 3-axis milling.

Continuous 5 axis CNC machining

Similar to their indexed counterparts, continuous 5 axis CNC machines can move in five axes. However, unlike indexed machines, continuous 5 axis CNC machines can move in all five axes without stopping. This means there are no pauses in the cutting process for the machine to reorient the workpiece or cutting tool.

The cutting tool continuously engages the workpiece as it moves and rotates in all five axes, creating a smooth, uninterrupted workflow. Continuous 5 axis CNC machining is faster and more capable than indexed machining, as it provides easier access to the workpiece and doesn’t have pauses. Conversely, it is more complex, requiring more sophisticated tool paths. In most continuous 5 axis CNC machines, the spindle provides rotational motion. The spindle or table may execute the linear motions. Continuous 5 axis machining is twice the cost of 3 axis milling.

Mill-Turning CNC Centres

5 axis CNC Mill-turning centres combine a lathe machine and a milling machine. Capable of both CNC milling and CNC turning operations, this hybrid machine produces more complex geometries than the individual machines can.

5 axis CNC Mill-turning centre

In most 5 axis CNC mill-turning centres, the spindle-mounted workpiece rotates along the A-axis. At the same time, a milling cutting head provides linear movement in the X, Y, and Z axes and rotational movement in the B-axis.

CNC machining operations compared: 5 axis machining vs other CNC machining processes

The table below compares the capabilities, pros, and cons of common CNC machines and machining operations.

Applications of 5 axis CNC machining

5 axis CNC machining is widely used across various industries due to its ability to create complex and precise parts. This operation is often used in the following sectors when highly complex geometries, precise details, and speed are required:

• Aerospace
• Automotive
• Medical Devices
• Energy (including oil and gas, wind, and solar power)
• Military and Defense

Generally, 5 axis CNC machining is an indispensable technology in industries where precision, efficiency, and quality are crucial.

Aerospace

5 axis CNC machining’s ability to produce complex part geometries with precision meets the stringent accuracy requirements of the aerospace industry. Components, such as turbine blades, structural airframe parts, and engine parts require the accuracy and quality that 5 axis machining provides. In addition, the ability to machine complex shapes in a single setup further reduces errors and enhances the reliability and performance of aerospace components.

Automotive

Precision is especially critical for transmission and engine components in the automotive sector. These components typically have complex geometries and are in continuous motion relative to each other. 5 axis CNC machining meets the demands required for these conditions, allowing for intricate designs and maintaining tight tolerances. This leads to improved performance, efficiency, and customization in vehicle manufacturing.

Medical Devices

Medical prosthetics and implants typically have intricate geometries that replicate body parts. An additional layer of complexity is added when these prosthetics are custom-made to fit specific patients. Furthermore, high accuracy, extremely tight tolerances, and quality surface finish are critical to the functionality and safety of medical instruments, implants, and prosthetics. 5 axis CNC machining is one of the few manufacturing processes that meet the rigorous standards of the medical industry, making it indispensable in the industry.

Energy

The energy sector, including oil and gas, wind, and solar power industries, benefits from the robustness and precision of 5 axis CNC machining. Components such as turbine blades, pump housings, and complex brackets require durability and precise engineering to operate effectively under harsh conditions. The capability to machine complex parts accurately in one setup makes 5 axis CNC machining ideal for these applications.

Military and Defence

5 axis CNC machining provides the necessary precision and capability to produce complex, specialised parts that meet the stringent requirements of military applications The defence industry demands high precision and reliability for components used in weapons systems, vehicles, and aircraft, as errors in these components can have grave consequences.

Prototyping and Custom Manufacturing

The flexibility of 5 axis CNC machining makes it invaluable for rapid prototyping and custom manufacturing. Designers and engineers can quickly create detailed and accurate prototypes, allowing for faster iteration and innovation. The ability to machine complex shapes in a single setup without the need for multiple fixtures or repositioning reduces production time and costs, making it an efficient choice for custom parts production.

Benefits of 5 axis machining

The ability to move in five axes gives 5 axis CNC machining numerous beneficial characteristics. Some of these are as follows.

Complex part geometries

5 axis CNC machines can produce very complex geometries. Many of the geometry restrictions that are inherent in 3-axis machining stem from the inability of the cutting tool to reach certain areas of the workpiece and make complex cuts. 5 axis CNC machining overcomes this problem, allowing it to produce highly complex geometries.

Provided you create a design according to CNC machining design guidelines, 5 axis CNC machining can create it.

Reduced machining time and effort

5 axis CNC machining can produce complete parts in one cycle and seldom requires pauses or breaks to reposition the cutting tool or workpiece manually. The increased automation results in a 30-40% decrease in production time and effort. Note, however, that these advantages are only obtainable in low-volume production. Machining time and effort increase exponentially in medium to large production runs.

Quality surface finish

The availability of the additional axes reduces vibrations during machining, allows for the use of more precise tools, and allows the cutting tools to be closer to the workpiece’s surface. These factors contribute to a higher-quality surface finish.

Limitations of 5 axis machining

While 5 axis machining is predominantly beneficial, it has the following inherent limitations.

High setup cost

The initial setup cost of 5-axis machining is relatively high, with high-end industrial 5-axis machines costing up to £150,000 - £1,000,000. Their use is mostly practical for geometries that cannot accurately be machined via 3-axis machining. Compared to 3-axis milling, Mill-turning operations typically cost 25% more, Indexed 5-axis machining 65% more, and continuous machining 100% more.

The difference in cost between indexed and continuous 5 axis CNC machining stems from the difference in the builds and complexities of their machines. Indexed 5 axis machines are less complex than continuous 5 axis machines. In these machines, the cutting operation occurs in three linear axes while the rotational axes serve to reposition the workpiece. The cutting pauses for rotational repositioning and resumes immediately after. Conversely, in continuous 5 axis machines, cutting proceeds in all five axes concurrently.

Complex programming

The additional two machining axes significantly increase the tool path programming complexity of 5 axis CNC machining operations.

Machining cost, time, and effort in large-volume production

By reaching multiple areas of the workpiece, 5 axis machining creates parts faster than 3 axis machining for one-off and low-volume production. However, machining time, effort, and costs increase exponentially for larger production volumes.  Due to the motions used in 5 Axis machining, the machines typically cut one part at a time. Therefore, an operator has to load and unload the machine for each individual part. This is in contrast to 3 axis machining, where multiple parts are machined simultaneously

Conclusion

The necessity of 5 axis CNC machining for your project predominantly depends on the complexity of your part. Geomiq offers advanced CNC machining services that are highly capable, fast, and compatible with numerous CNC machining materials. Simply head over to our instant quoting platform to upload your part, and our team of manufacturing experts will determine the best machining technique for your part. You can also contact us to request 5 axis CNC milling specifically