CNC machining has grown to be one of the most critical manufacturing processes used in workshops worldwide. The addition of computer control to a previously manual process has produced leaps in accuracy and precision in machined parts.
Furthermore, due to increasingly complex requirements in various industries, CNC machines have undergone multiple evolutions to serve customers’ needs better.
The evolution in CNC machining technology has given rise to various forms and variations of the technology. These include the 3-axis, 4-axis, and 5-axis CNC machines.
As a leading provider of CNC machining services, we often get questions from customers about how these technologies work. So, we decided to shed more light on them with this article.
This write-up will focus on how each technology works, its advantages, disadvantages, and applications. Most importantly, we’ll show you how to choose the best type of CNC machining for your project.
So, let’s start with the 3-axis CNC machine.
What is 3-axis CNC Machining?
3-axis CNC machining is the simplest and most common form. This process uses a rotating cutter moving along 3-axes to machine a stationary workpiece.
The cutting tool moves along the X, Y, and Z-axis to trim the excess material from the part. In addition, it can even move along these multiple axes simultaneously to create the required design.
This means that a CNC machine can cut from side to side, front to back, and up and down into the workpiece. However, the workbench holding the workpiece is not free to move at all.
Although more advanced systems are available in the Industry today, 3-axis CNC machining still enjoys widespread use. So, let’s take a look at some of the advantages of keeping it in favor.
√ Low Cost
3-axis CNC machining is the best for producing basic geometries and simple components rapidly. Furthermore, in 3-axis machining, it is relatively easy to program and set up the computer for production runs.
3-axis CNC machining is a highly versatile process for making parts. You can perform various operations like drilling, milling, and even turning by simply changing the cutting tools.
The machines are also integrated with automatic tool changers, which expand their capabilities.
3-axis machining is also hamstrung by several factors that prevent it from being suitable for all machining needs. Some of these factors include:
√ Design Limitations
With 3-axis CNC machining, you are limited to only basic shapes and geometries, for example, it can not create the under cut features. Although the machine can do much more in the hands of a skilled machinist, it still can’t match the complex shapes obtainable with 4 and 5-axis CNC machines.
Also, it is not suitable for machining parts with special deep features or narrow cavities.
√ Multiple Setups
Since the workbench that holds the workpiece is stationary, the machinist has to change its orientation several times to machine its other faces.
This repositioning can lead to a loss of accuracy, not to mention the amount of time lost doing it.
√ Poor Surface Finish
The surface finish obtained with 3-axis machining is relatively poor, especially on Z-cuts. This happens because the cutting tool is long. Therefore, it experiences more vibrations which can ruin the product’s finish.
3-axis CNC machining is still a very useful process. We can use it to create a variety of basic geometries with a high level of precision.
These applications include;
- 2 and 2.5D pattern engraving
- Slot and face milling
- Threading holes in line with the machine axis.
- Drilling, etc.
What is 4-axis CNC Machining?
4-axis CNC machining offers a notable upgrade over 3-axis machining. It adds an extra degree of freedom through a rotating movement, making machining complex features possible and more straightforward.
In the 4-axis CNC machining, the cutting tool is free to move about in the X, Y, and Z axes to machine the workpiece. However, the workpiece isn’t stationary on the workbench as in 3-axis machining.
The 4-axis CNC machine can rotate the workpiece around the X-axis in a plane known as the A-axis. So, as the tool moves along the workpiece and the worktable turns it, you can make cuts all along the workpiece’s profile.
Many advantages come from selecting 4-axis CNC machines for your manufacturing projects. Here are some of them
√ Greater Design Complexity is Achievable
Due to the worktable’s rotation about the X-axis, the 4-axis CNC machine can produce complex detailed parts. In addition, the extra rotation enables it to access and machine parts on other faces and at odd angles to create the final part.
√ High Precision and Accuracy
The 4-axis CNC machines can access multiple faces of the workpiece without needing adjustments or fixture changes. As a result, parts made with it are incredibly accurate and precise to exacting standards.
√ Higher Speed and Lower Production Costs
Most work done on the 4-axis CNC machine requires only a single clamping. As a result, the work can go on smoothly without needing downtime or interventions to change fixtures and tooling.
Also, since multiple fixtures are not needed for holding the parts, the production costs decrease dramatically, especially when compared to 3-axis machining.
4-axis CNC machines also have some flaws that may render them unsuitable for some customers. Let’s look at them.
√ High Running Costs
The cost of operating a 4-axis CNC machine compared to running a 3-axis CNC machine is relatively higher. This is due to the machine’s extra features and the specialized labor required to operate the machine.
4-axis CNC machining opens up a wide variety of manufacturing possibilities. Some of its applications include:
- Curved geometries
- Engraving or machining cylinder sides and profiles
- Turning and milling (On the same machine).
- Cutting side holes and pockets.
What is 5-axis CNC Machining?
5-axis machining is the most accurate, cutting-edge method for creating complex, precise metal parts on shop floors.
In a 5-axis CNC machine, the cutting tool moves about in the X, Y, and Z-axis, just like in the 3-axis machine. In addition to this, the workbench can also rotate the workpiece about the X and Y-axis.
These planes of rotation are known as the A-axis and the B-axis, respectively.
These extra rotations open up other faces of the workpiece that were erstwhile inaccessible for machining. So, with a 5-axis machine, accurate 3D machining is possible thanks to the machine moving in the XYZ axes and rotating in the A and B planes simultaneously.
What is The 3+2-axis Machining?
Some people tout 3+2-axis machining as the same thing as 5- axis machining, but that is just not true. Although both can move in the same direction, they do not do so in the same way.
In a true 5-axis milling machine, the cutting tool can move in the XYZ axis while the worktable turns in the A and B axis simultaneously. However, this simultaneous motion is not possible in the 3+2 axis milling machine.
The 3+2-axis machine can only move the worktable by rotating it along the X and Y axis before cutting starts. It cannot do so in real-time while cutting is happening on the XYZ axes.
There are many advantages to using a premium 5-axis CNC machining service.
√ Complex Part Creation
5-axis CNC machining is very popular in the aerospace, automobile, and energy industry for this very reason. The addition of a 4th and 5th axis makes machining complex parts a piece of cake for the 5-axis CNC machine.
It can handle a wide variety of curved geometries, narrow cavities, overhanging features, etc., that other machining methods cannot even begin to cover.
√ Reduced Lead Times
Manufacturing parts with a 5-axis CNC machine is a very speedy undertaking. It does not require multiple setups to change fixtures or part orientation. In one single step machining process, it can create incredibly complex shapes.
√ Incredible Surface Finish
Thanks to the 4th and 5th axis movement, the 5-axis machine can orient parts closer to the cutting tool. This results in cleaner, more accurate cuts leading to a stellar surface finish.
The only drawback of 5-axis CNC machining lies in its cost. The premium services and features it provides make it more expensive than 3 and 4-axis machining.
However, for applications that require that extra high quality, this additional cost is worth it.
Some typical applications of 5-axis machining include:
- Machining complex shape parts such as car plastic lens, billet compressor wheel
- Creating tilted surfaces
- High accuracy, low tolerance applications
Difference Between 3-Axis, 4-Axis, and 5-Axis CNC Machining
As seen in the article, there are many differences between 3, 4, and 5-axis machining. Let’s go through a quick rundown of how they differ from each other using these factors.
√ Manufacturing Capability
When it comes to manufacturing capabilities, 5-axis CNC machining stands clear on top. It is capable of machining complex shapes, intricate details, and excellent surface finishes.
The 4-axis milling machine is a close second. We can use it to create and etch designs on the profiles of cylindrical parts like camshafts.
At the bottom of the pole is the 3-axis CNC machining, which is only suitable for basic geometries and 2 and 2.5D designs.
√ Axis of Movement
The 3-axis CNC machining is capable of cutting in three axes (X, Y, Z). The 4-axis CNC machining adds a rotational axis around the X-axis (A-axis).
Finally, the 5-axis CNC machine adds on more axis of rotation around either the Y or Z axis (B-axis).
Machining a part depends on a lot of factors. If we are talking about the setup costs, then the 3-axis machining is the most expensive because parts with multiple faces require multiple fixtures and cannot be machined in one go.
While 5 and 4-axis CNC machines can make use of CNC tombstones o reduce setup costs and increase productivity simultaneously.
However, if we consider machining cost per hour (running cost), then the 5-axis CNC machining is much more expensive thanks to the extra features it provides.
In some cases, you can offset some of the costs by using a CNC tombstone or large production runs.
How to Choose The Correct CNC Machining Method?
Choosing the correct method is essential to getting the best possible final product, and we are here to help you with that.
In our manufacturing experience, the primary consideration in the minds of most customers is always cost. Although the cost is significant, it should not be the primary focus.
Therefore, in our experience, the best way to decide which CNC machining method is optimal for your project is first to determine your quality requirements.
Once you determine the quality and grade of products you need, you can factor in the cost and make adjustments.
√ Part Complexity
Part complexity is the most significant factor you always have to consider when choosing a CNC machining method. If you go with the wrong approach, the chances are that you’re not going to get what’s in your design.
In some cases, choosing the wrong CNC machining method can even result in higher production costs. So, when choosing, go with a CNC machine capable of reproducing your design faithfully.
√ Accuracy, Tolerance, and Surface Finish
All CNC machining processes produce high-quality, accurate parts with great surface finishes. However, there are tiers to this accuracy.
For example, a part needed for a kitchen fixture may not require the same accuracy as a part intended for medical or aerospace use. Furthermore, to produce the grade of precision required for aerospace applications, you cannot use a 3-axis CNC machine.
Thus, you have to consider the type of accuracy the part requires in its intended applications.
Turnaround and lead times should also factor into your decision. For example, if you are in a hurry to get the products to market or the parts are time-sensitive, a method like 3-axis machining might not be for you.
In this case, it’s better to pay the additional cost and go with a faster method like 4-axis CNC machining. This way, you get your parts faster and satisfy your customers.
Finally, this should be the last and most crucial factor to consider. After you have decided on your product’s requirements and the type of quality you want, it’s time to balance it with your budget.
To do this, you’ll need a top-notch machining service that can provide cost-effective manufacturing solutions for your projects. This is where RapidDone comes into the picture.
Contact us Today
RapidDone is a leading provider of CNC machining services in China. We have many years of manufacturing experience in producing both end-use parts and prototypes using machining techniques on our shop floor.
Our factory is well-stocked with cutting-edge CNC machines complemented by experienced Engineers and technicians. Therefore, when you go with RapidDone, you know you are getting the best quality possible.
So, contact us if you want to know about the machining. At the same time, if you have a quote project, you can send your drawings, designs, or plans, we can offer a high-quality, cost-effective manufacturing solution today.