In the world of CNC machining, multi-axis machines have become the go-to for top-notch precision, efficiency, and versatility. These machines set themselves apart from the typical stationary or two-axes linear machining process as they involve more complex features, functions, and applications.
Due to their extra axis, they can easily create intricate parts without compromising high precision qualities.
Three of the most popular CNC machines today are the 3-axis, 4-axis, and 5-axis. While these three fall under the same category of CNC machining, each is distinct from the others and offers specific advantages.
In this guide, you’ll learn more about the fundamentals and key features of these three CNC machining processes.
What is 3-Axis CNC Machining?
The 3-axis CNC machine is the entry-level for multi-axis machining. As you may know, the word axis in CNC machining denotes the number of directions the cutting tool can move through. Hence, in the case of 3-axis CNC machining, the cutting tool can move in the directions of the x-axis, y-axis, and z-axis.
The x-axis allows the cutting tool to move from left to right, the y-axis facilitates the forward and backward movement, and the z-axis for up and down cutting direction.
These three mutually perpendicular directions allow the machine to work on a mounted workpiece with better speed while minimizing the manual repositioning of the workpiece.
Benefits of 3-Axis CNC Machining
While 3-axis CNC machining remains the simplest multi-axis CNC machining process, it still offers robust benefits that make it popular across various industries.
Here’s why investing in 3-axis CNC machining is a worthy consideration:
Simple Operation and Cost-Effectiveness: One of the most significant upsides of 3-axis machines is their relatively simple operation compared to higher-level multi-axis machines, making them more affordable.
This simplicity often translates into lower setup and operational costs, rendering it a practical choice if you’re involved in a straightforward machining project.
Versatility: While they may be limited to three linear directions, 3-axis machines remain flexible. They remain promising in handling various materials and part types, from basic shapes to more intricate designs, provided the workpiece is easily accessible from the top.
Ease of Setup and Maintenance: With fewer moving parts and a less complex setup, 3-axis machines will not burden you with high maintenance and calibration challenges, cutting downtime and improving reliability.
Limitations of 3-axis CNC Machining
There’s no doubt that 3-axis CNC machining is a valuable integration into various manufacturing industries. However, they remain aptly limited to fewer operations and capacities.
Here are some downsides of 3-axis CNC machining:
Limited Access to Complex Geometries: 3-axis machines are not the ideal cutting tools for creating complex parts.They are likely to struggle with designs that have tight tolerances, odd angles, and more complex angled features.
Need for Multiple Setups: Parts requiring machining on multiple sides may need to be repositioned several times, increasing setup time.
Increased Handling and Labor: Manual repositioning of parts for different sides can lead to errors and require more labor.
Reduced Capability for Complex or Curved Surfaces: Intricate, curved, or angular features are difficult to machine accurately with a 3-axis machine.
Tooling Limitations: The fixed approach angles limit the types of tools that can be used and may increase machining time.
When Choose 3-Axis CNC Machining
There are a handful of factors that you should consider before sticking to 3-axis CNC machining. Among the most important include the material you’ll be working on, the design complexity and geometries, the operation speed, and budget considerations.
A 3-axis CNC machine is enough if you’ll only be focused on the woodworking industry or crafting simple 2D and 3D geometric patterns on plastic or soft metals. If you’re after high precision and speedy machining operations without high upfront investment, a 3-axis machine is your top pick.
What is 4-Axis CNC Machining?
4-axis CNC machining is simply a 3-axis machining process that is a notch more complex and versatile. The 4-axis CNC machine includes an extra axis to the 3-axis’s X, Y, and Z cutting direction.
But this time, the extra axis corresponds to rotational axes, categorized as the A axis. This additional rotary axis allows for a more continuous machining process that the 3-axis may struggle with.
The additional A axis often rotates the workpiece along the horizontal cutting direction or the X axis, allowing complex geometries and angled cuts.
Benefits of 4 Axis CNC Machining
Here are the key upsides of 4-axis CNC machining:
Increased Machining Flexibility: No doubt, 4-axis CNC machining elevates the versatility of the process by adding turning operations. The additional axis makes 4-axis machines the appropriate cutting tools for more intricate workpieces.
Improved Efficiency and Simplified Setup: With its continuous and simultaneous machining process, you can significantly boost the operation speed while cutting on the setup time. Often, this process produces complex CNC-machined parts in a single setup.
Higher Precision and Accuracy: Since you’re not only working in three linear axes, the accuracy of your machining work is also guaranteed to improve. The added axis gives you better control of the workpiece, therefore delivering higher precision cuts on different angles.
Limitations of 4-axis CNC Machining
On the other hand, 4-axis CNC machining has its downsides as well.
Complexity in Programming: Since 4-axis CNC machining involves more movement, you can expect a more complex programming. It also requires higher-level software for advanced toolpath planning and increased simulation.
Higher Cost: Besides the higher upfront cost, a 4-axis machine, like a 4-axis milling machine, also includes higher maintenance costs and energy consumption. CNC milling machines also ask for more costly software and personnel training, all contributing to higher operational costs.
When Choose 4-Axis CNC Machining
Choose 4-axis CNC machining when you need to machine complex parts that require rotation for precise multi-sided machining in a single setup. It’s ideal for cylindrical parts, intricate detailing, or jobs where reduced cycle times and fewer setups are essential. It strikes a balance between cost, flexibility, and complexity, offering more versatility than 3-axis machining.
What is 5-Axis CNC Machining?
5-axis CNC machining expands on 3-axis and 4-axis machining by adding two additional rotational axes (typically the A and B axes) to the traditional X, Y, and Z linear movements. This allows the cutting tool or workpiece to move in five simultaneous directions, enabling more complex and precise machining.
The added axes allow for the machining of intricate geometries, undercuts, and multi-angle features in a single setup, reducing the need for repositioning. Ideal for high-precision industries such as aerospace, automotive, and medical, 5-axis CNC machining improves efficiency and accuracy while allowing for the production of highly complex parts.
Benefits of 5-Axis CNC Machining
5-axis CNC machining offers several key benefits:
Enhanced Precision: It allows for precise machining from multiple angles, reducing errors from misalignment or repositioning, ensuring tight tolerances and high-quality parts.
Reduced Setup Time: Parts can be fully machined in a single setup, eliminating the need for multiple fixturing and part handling, which boosts productivity and minimizes errors.
Greater Flexibility: It enables the creation of complex geometries and intricate designs, such as undercuts and angled features, that are challenging or impossible with 3-axis or 4-axis machines. This flexibility is ideal for industries requiring high-precision, complex parts.
Limitations of 5-axis CNC Machining
As versatile as they come, 5-axis CNC machines still have some limitations. Here are the areas where they may fall short.
Skill and programing requirements: 5-axi CNC machining is one of the most complex to operate, hence requiring high level of expertise and programming software.
Affordability: The machine’s impeccable flexibility and performance come with a higher price tag. This advanced CNC machining tool is often limited to a bigger production line, like the aerospace industry, where complex parts are the usual focus.
When To Choose 5-Axis CNC Machining
5-axis CNC machining is among the more exclusive lines of CNC machines. It should only be a significant investment if you’re in an industry that involves advanced machining parts or a more demanding product manufacturing industry where utmost precision is required.
Differences Between 3 Axis,4 Axis and 5 Axis CNC Milling
While all fall under the category of multi-axis CNC machining, these three types of computer-aided manufacturing milling machines are distinct from one another. Here are the areas where they differ the most.
Cost: Basically, the more tool moves a CNC machine has, the more complex machining parts it can create and the higher its cost. Among the three, 3-axis CNC machining is the most affordable, with the price increasing as more axes are added.
Flexibility: The three axes CNC machining process is flexible enough for simple, flat parts. The 4-axis CNC machining can do well in more complex parts due to its added rotational axis. The 5-axis CNC machining process is the most versatile due to its more flexible rotational movement; hence, it’s more efficient and convenient in creating complex parts.
Rotation in Axes: This aspect separates 3-axis CNC machining from 4-axis and 5-axis CNC machining. 3-axis CNC machining lacks rotational movement and is limited to three axes. Meanwhile, both 4-axis and 5-axis CNC machining employ rotational axes.
The only difference between the two is that the additional a-axis (or b-axis) for the former can only rotate around a single axis. In contrast, 5-axis CNC machining can rotate along the a-axis and b-axis.
Programming: The one with the highest number of tool movements also has the most complex programming. 5-axis CNC machining need the most advanced programming, often requiring high level of expertise.
Accuracy: All these CNC machining types offer great accuracy when producing parts. However, their accuracy is limited to the movements available to them.
In the end, 5-axis CNC machining offers the highest accuracy as it can produce parts in continuous machining, limiting errors from minimal setups and tool changes.