CNC (short for Computer Numeric Controlled) machining is a process not new in the manufacturing industry. In fact, it has played a crucial role in moving industrial development forward and has been pivotal in helping build the world as we know it.
However, technology continues to evolve. And with it comes an increase in demand for highly complex and intricate parts like those used in the aerospace and automobile industries. Your traditional CNC machining processes become less efficient in the face of these rising part complexities.
This is where 5-axis CNC machining comes in.
5-axis CNC machining is a remarkable innovation in the world of part manufacturing. This type of machining offers numerous advantages over the typical 3-axis and 4-axis CNC machining.
What is the major difference between 5-axis and 3- and 4-axis machining? We will answer this and more in this blog.
Understanding CNC Machining
If you are new to the world of CNC machining, it might be worth spending some time understanding what the process is and how it works before diving into the complexities of the multi-axis processes.
CNC machining is a process used to make parts and components of various geometrical shapes, sizes, and functionalities using materials like plastics, metals, or composites. It does so by removing the material from a block of the raw material, say metal, using a sharp cutting tool.
The cutting tool or the part moves according to the design to machine the part in the right places and make the required design.
This is why CNC machining is also sometimes called a subtractive manufacturing process – since it removes the material from a block of solid raw material.
How does the cutting tool know where to cut? This is where the CNC part comes in.
The machine is told what to do and where and how to cut through a computer program. The designers code the program into the machine’s computer. This computer then controls the tool and other components, creating the required parts.
Since the process is largely controlled and executed by a computer, CNC machining, by default promises high precision and machining accuracy. However, the precision and accuracy may increase or decrease based on the number of axes involved. We will talk more about this in a bit.
Understanding 3, 4, and 5-axis CNC Machining
We have already discussed how the world of CNC machining has evolved quite a lot since its earliest days. Today we have machines that can cut across multiple axes to improve part finish and accuracy even further.
A CNC machine may range from the basic 2-axis lathe to the highly complex 9-axis machine. But we will keep our conversation circled around the 3, 4, and 5-axis CNC machines.
Before we dive into the major and other smaller differences between the three machining processes, let’s spend some time understanding how each of these works.
3-axis CNC Machining
As the name suggests, the 3-axis CNC machining allows the cutting tool or the workpiece to move along three linear axes namely the X, Y, and Z axes. In other words, the cutting tool or the part can move left to right, up and down, and in and out during a 3-axis machining process.
Because of the machining process’s ability to cut along three linear axes only, it has its limitations when it comes to manufacturing complex or angeled parts. However, with its limitations, the 3-axis machining process may appear to be more economical for simple parts. Not so much for the complex ones though.
4-axis CNC Machining
4-axis CNC machining is similar to 3-axis machining in that the tool can move along the three linear axes i.e. the X, Y, and Z axes. The only difference here is the addition of another axis called the A-axis that allows the part to rotate along one of the linear axes, usually the X-axis.
This seemingly small difference has a huge impact on the process’s capability of handling complex part manufacturing projects.
The 4-axis CNC machining process can manufacture angeled and complex parts with greater ease as compared to the 3-axis machining.
5-axis CNC Machining
The 5-axis CNC machining process adds another axis of rotation to the 4-axis process, increasing the machine’s capability of handling highly complex parts that require unusually intricate and precise machining.
In addition to the three linear axes i.e. the X, Y, and Z axes, two rotational axes are also added which allow the tool or the part (depending on the type of 5-axis machining) to rotate along two of the linear axes.
The Major Difference Between 3 and 4-Axis and 5-Axis CNC Machining
The 5-axis machining unlocks newer dimensions for the tool to work through and create complex parts with unparalleled precision and accuracy. And this is the most significant factor that sets 5-axis machining apart from the traditional 3 and 4-axis machining.
The availability of the A and B axes for tool or workpiece rotation also opens up newer possibilities of manufacturing parts that are either downright impossible or just plain impractical to manufacture using the 3 and 4-axis machining processes.
This simple difference between the number of available axes for the tool or workpiece to move along leads to numerous other differences between the advanced 5-axis and the traditional 3 or 4-axis process.
Some of these differences include:
Economy
Yes, 5-axis machines may come with a daunting price tag. The machine may seem more expensive, especially when you compare only the upfront cost of the 5-axis machine with the traditional 3 and 4-axis ones. However, when you look at the bigger picture, you can see how the 5-axis mill may help you save costs, especially when machining complex parts.
You can manufacture parts with only a set level of complexity using 3 and 4-axis machines, that too with the addition of certain expensive fixtures. This adds to the operational cost and restricts your shop’s production capability.
As opposed to this, you can create increasingly complex parts without additional, pricey fixtures using the 5-axis process, which makes it more economically viable. These parts may also sell at a higher price, resulting in increased ROI.
Cycle Time
5-axis machines can provide continuous milling, even when working on complex parts, a capability missing from the traditional 3 and 4-axis machines when working on similar parts.
Moreover, since 5-axis machines allow rotation along 5 different axes, you can mill on various sides of the workpiece and at various angles without removing and reorienting the part.
You may have to remove the workpiece from the machine and reorient it when performing a similar machining operation with a 3 or 4-axis machine. This may add to the cycle time and lead to inaccuracies in the design.
The 5-axis machine also removes more material per pass. This is another feature that leads to lower turnaround and increased operational efficiency.
Scrap and Wastage
You know how a 5-axis machine can offer continuous operation which eliminates the need to set up the part again and again. This brings down the chances of human errors and reduces part wastage and scrap.
Reduced Need for Manual Labor
When you have to change the part orientation constantly there is a need for additional human labor. Since a 5-axis machine is capable of machining along all sides, it eliminates the need for human intervention. This reduces your reliance on human labor and also allows you to minimize the inevitable human errors that come with human intervention.
Conclusion
CNC machining is a decades-old process with the first CNC machine being manufactured in 1952.
The world of CNC machining has evolved quite a lot and come a long way since then with numerous innovations, mostly aiming to make the production of complex parts more efficient.
One of these innovations is 5-axis CNC machining, a feat of engineering that machinists could possibly only dream of during the early years of CNC machining.
5-axis CNC machining is more capable, efficient, and cost-effective when it comes to manufacturing highly complex and intricate parts, especially when compared to the performance of 3 and 4-axis machines for producing the same design.
5-axis machine, courtesy of the benefits it offers, may also be viable for machining non-complex parts. However, the decision of whether you want to invest in a 5-axis machine vs a 3 or 4-axis one would boil down to your shop’s requirements.
