3-Axis Vs 4-Axis Vs 5-Axis Machining: Their Difference
You are probing the differences between 3, 4, and 5-axis machining and want to know which is best for your use. We understand it can be hard to identify and choose a top quality 4 axis CNC machining machine when you are new to manufacturing. But worry not, we will explain what separates them and finally, you will have a clear understanding of how many axes your parts and projects need.
What is 3-Axis Machining?
3-axis machining involves the three-dimensional movement of a cutting tool along the x, y, and z axes. In this case, the x and y axes make it possible for the cutter to move alongside with workpiece while the z axis enables it to move across the surface of work itself. Consequently, such a motion of a tool can penetrate the material.
What Can a 3-Axis CNC Do?
With just three axes of motion, a 3-axis CNC can perform many useful operations and functions like cutting, drilling, and routing of wood, plastics, and soft metals.
Cutting
A 3-axis CNC can accurately cut materials to specific shapes and sizes. Whether you need rectangles, circles, or complex contours, a 3-axis machine can handle it. It allows you to cut materials efficiently and with a high degree of repeatability.
Drilling
A 3-axis CNC can drill holes in precise locations. It can drill holes in linear paths, circular paths, or specific X-Y coordinates. You can drill holes of varying depths and diameters. A 3-axis CNC drill provides fast, accurate hole drilling that would be difficult to achieve manually.
Routing
A 3-axis CNC router can cut grooves, engrave text or images, and make decorative edge profiles. With a router mounted as the cutting tool, a 3-axis CNC can quickly and accurately route materials. Different router bits allow you to achieve different routing effects. Routing with a CNC allows complex routing that would be nearly impossible to do by hand.
Benefit Of 3-Axis Machining Process
Cost-Effective
Affordability is one of the main advantages of going with 3-axis CNC machining over 4- or 5-axis systems. The cost of these computer-numerical-controlled machines in question is usually low. Furthermore, they tend to be much easier to program as well as operate thus less extensive training must be given to these employees. Therefore, running costs could be minimized in this way eventually.
Precise and Repeatable
The dimensional accuracy and repeatability of parts machined on a 3-axis CNC machine can be very high. Provided that the machine is correctly tooled and calibrated; it should produce exactly similar part-time after time again. Hence, such an aspect is perfect for mass production where uniformity takes precedence over everything else.
Simple Geometry
3-axis machining works well for parts with simple, geometric shapes. It can efficiently handle cuts like pockets, slots, holes, and contours with a straightforward path. More complex parts with irregular shapes or hard-to-reach features may require the additional axes of movement provided by 4- and 5-axis machining.
Rigid and Stable
The 3-axis CNC machine has a simple, rigid design. With fewer moving components, there is less chance of instability or vibration during the machining process. This rigid, stable platform helps the cutting tool achieve clean, accurate cuts and a good surface finish. For some materials and cutting operations, stability is essential.
Limitation Of 3-Axis Machining
3-axis machining only allows movement in X, Y, and Z linear axes, restricting the complexity of parts that can be produced. You’re limited to basic features like slots, pockets, and holes in a straightforward orientation. Any undercuts, contours, or angles in multiple planes are off-limits. If you need to produce complex, sculpted surfaces or intricate 3D shapes, 3-axis machining just won’t cut it.
Lower Productivity
The limited capability and increased difficulty of 3-axis machining ultimately means lower productivity. When parts require frequent repositioning or multiple setups to complete all features, more time is spent away from actually cutting material. The ability to access part features from multiple angles in a single setup, as with multi-axis machining, significantly boosts productivity and throughput.
Restricted Materials
3-axis machining also limits the types of materials that can be cut efficiently. Softer materials like aluminum and plastics are well suited to 3-axis methods, but harder materials require more advanced equipment. Machining steel, titanium or nickel alloys on a basic 3-axis machine would be difficult and time-consuming, producing poor results. For these more complex materials, the power and flexibility of 4- and 5-axis machining is essential.
What is 4-Axis Machining?
Four-axis machining adds an extra level of flexibility, performance, and precision to every step of the manufacturing process.
While 3-axis machining moves along the X, Y, and Z axes, 4-axis machining adds rotation around one of these axes, allowing the cutting tool to reach more areas of the workpiece. This additional axis of movement means that 4-axis CNC machines can produce more complex, sculpted parts with curving contours.
What Can a 4-Axis CNC Do?
With just three axes of motion, a 3-axis CNC can perform many useful operations and functions like cutting, drilling, and routing of wood, plastics, and soft metals.
Complex Geometry
The extra rotary axis on a 4-axis CNC opens up more complex geometries that were previously unachievable. You can now machine parts with sloped, angled surfaces in a single setup.
This includes parts like impellers, turbine blades, and propellers that require precisely angled cuts. The A-axis rotation allows the cutting tool to smoothly transition between different angles, cutting the entire sloped surface in one pass.
Improved Productivity
For many parts, a 4-axis CNC can improve productivity over a 3-axis machine. Because you can cut angled surfaces in a single setup, there is no need to manually reposition the part to access different sides.
The fourth axis handles the orientation automatically. This reduces setup time and labor costs, allowing for faster turnaround times and lower part costs.The ability to machine more complex parts also opens your shop up to new jobs that were not previously possible.
Benefit Of 4-Axis Machining
Compared to 3-axis machining, 4-axis machining offers significant weight and performance benefits for manufacturing lightweight and complex parts. With the addition of a rotary axis, 4-axis machining allows cutting from different angles using cylindrical and spherical toolpaths. This means you can machine parts with complex geometries that would be difficult or impossible with only linear axes.
Increased flexibility
Four-axis machining provides more flexibility in terms of the shapes and forms you can create. Parts with contours, curves, and complex geometries—like impellers, turbine blades, and propellers—can be machined efficiently. The rotary axis allows the cutting tool to approach the workpiece from any angle, giving you more options in toolpath programming. This expanded range of motion produces machined parts with superior surface finish and accuracy.
Reduced setup time
With 4-axis machining, you can machine multiple part features in a single setup. This reduces the number of setup changes needed, decreasing production time and labor costs. Multiple operations like milling, drilling, and tapping can be performed on one machine. The rotary axis provides access to all areas of the workpiece, so you don’t have to reposition the part for different operations.
Improved productivity
Four-axis machining boosts productivity in several ways. The ability to machine complex parts in a single setup reduces non-cutting time. More efficient toolpaths also mean shorter cycle times. And because 4-axis machining produces higher quality parts with tighter tolerances, there is less scrap and fewer parts that require rework. Overall, 4-axis machining can significantly speed up production and lower manufacturing costs.
Limitation Of 4-Axis Machining
While 4-axis machining opens up more design possibilities than 3-axis machining, it still has some limitations. The fourth rotary axis can only rotate the part in a single horizontal plane. This means undercuts, contours, and complex geometries designs that require movement in multiple planes at once are off-limits.
If you need to machine parts with complex, curved shapes or contours, a 4-axis machine may struggle. The linear axes (X, Y, and Z) can only move so many directions as fast, and the rotary axis has to continually reposition to access all areas of the part. This problem can lead to excessively long machining times. In some cases, a 4-axis machine may not even be able to produce the required tool paths to machine the most complex parts.
Tool accessibility is another downside. The rotary table or trunnion mount that holds the workpiece can block access for some tools. As the part is repositioned, tools have to be able to reach and touch all required areas. Some machine configurations and work-holding and life support methods may limit which tools can be used.
The range of motion the motor has for the center rotary axis can also be a limitation. Most 4-axis machines offer between 360 and infinite of center rotation, but some other motors may be limited to 180 degrees or less. If your parts require more center rotation than the machine offers, you’ll need an alternative solution.
What is 5-Axis Machining?
In the world of CNC machining, 5-axis machining is the most advanced option available. Unlike 3-axis or 4-axis machines that move along the X, Y, and Z axes (left-right, front-back, and up-down directions), 5-axis machines have two additional rotary axes that tilt and rotate the part. This allows the cutting tool to approach and enter the part from any direction you choose.
What Can a 5-Axis CNC Do?
A 5-axis CNC machine opens up a whole new world of possibilities for complex part machining. With the weight and support of two additional rotary axes over a 3-axis machine, the cutting tool can approach the workpiece from almost any direction. This change allows you to machine parts with complex geometries that were previously very difficult or impossible to make.
Compared to 3-axis and 4-axis CNCs, a 5-axis system provides far more flexibility, performance, and versatility. The multi-directional cutting ability lets you efficiently machine irregular shapes, contours, and geometries. Parts like impellers, turbine blades, and other components with twisted or sculpted surfaces can now be fabricated with a single setup to save further money. You can also perform simultaneous 5-axis roughing, profiling, and finishing in a single operation to save further.
With 5-axis machining capabilities, you have access to more of the workpiece, allowing for shorter tool paths, fewer tool changes, and less wasted material. This functionality can significantly reduce overall machining time and cost. The additional axes also provide more opportunities for automated toolpath data generation capabilities, minimizing the need for complex CAM programming.
Benefit Of 5-Axis Machining
Some of the main benefits of 5-axis CNC machining include:
Increased geometric flexibility. You can produce organic, sculpted shapes that were previously very difficult to make.
Improved part accuracy. The multi-directional approach means fewer setups and workpiece repositioning, reducing errors.
Reduced machining time. Shorter tool paths, single setup operations, and less wasted material lower total cycle times.
Less human programming. Advanced CAM software can automatically generate optimized 5-axis toolpaths, minimizing manual programming.
Higher quality surface finishes. The multi-axis cutting ability provides a more even tool load and cutting, resulting in better part surface quality.
Limitation Of 5-Axis Machining
While 5-axis machining opens up a whole new world of possibilities for manufacturers, it does come with some limitations to be aware of. For one, 5-axis machines are more complex, so they tend to be much more expensive than 3-axis or 4-axis CNC machines. The additional axes also require more advanced programming to control the machine, so you’ll need software and employees with the proper experience and training to monitor and support them.
Additionally, 5-axis machining typically has a slower feed rate, so cycle times can be longer. The slower speed is necessary to allow the machine to move and position the part properly along multiple axes of motion. Parts with deep pockets or complex geometries in particular can take a significant amount of time to machine. Some 5-axis machines are also limited in some form of the number, size and weight of parts they can handle due to the additional axes of motion.
Another limitation customers have is that 5-axis machining may require multiple tool changes to complete all the necessary cuts. While a 3-axis machine can often machine a part with a single tool, 5-axis machining frequently needs different tools to have customers access parts from different angles. This results in longer setup times for customers and can reduce bottom line efficiency.
Conclusion
So there you have it – the key differences between 3-axis, 4-axis, and 5-axis CNC machining are summarized. While the 3-axis gets the job done for a lot of parts, stepping up to add 4 or 5 axes opens new doors of capabilities, functions, capabilities and abilities. The tradeoff is added complexity and cost.
Think through what you need for your application before deciding. And don’t forget – your qualified machine shop can help advise you on the best option if you tell them about your part design and end goals.
Author
Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.