Intro
When designing a part, you should consider which machine will run the part. This entails learning about the different CNC machines on the market. If you’ve done some research, you’ve probably heard machines referred to by how many axes they have.
Commonly, you’ll hear about 3-axis, 4-axis, and 5-axis CNC machines. Which of them is better, and what do the axes even do? In this quick guide, we’ll answer these two questions and help you better understand what happens on the floor of a machine shop.
Understanding What the Axis Does
The axis of a CNC machine tells you what type of motion the machine can do. Each of these axes refers to a direction.
In a 1-axis machine, the cutting head can only go one direction:
- Up and down
- Side to side
- Or back and forth
As you add more axes, you’ll unlock more motion.
What Is a 3-Axis CNC Machine?
A 3-axis CNC machine has quickly become the standard in most machine shops. The cutting head can move in all three directions: in the x-direction, y-direction, and z-direction.
You can theoretically change the height and width of the piece without changing how it’s held in the vice.
What Is a 4-Axis CNC Machine?
The added 4th axis in a 4-axis CNC machine unlocks rotation. This “A-axis” will change the angle of either the material or the cutting head along one of the previous three axes. In other words, the part can rotate around the x-axis and move in the x, y, and z directions.
You can create more complicated parts with rotation. The machine can cut non-orthogonal holes or trim rounded features without the need for complex jigs or workholding solutions.
What Is a 5-Axis CNC Machine?
As you might have guessed, a 5-axis CNC machine’s new axis is another form of rotation. With the added “B-axis” or “C-axis,” the machine can rotate about two different linear axes allowing for even more complicated cuts and impressive machining.
Which Is the Best CNC Machine Option?
To better understand which CNC machine option is right for your project, take a look at this list of considerations to make.
Make More Complicated Parts
Regarding the additional 4th and 5th axes, machining parts are simpler, and objects can be more complex. Non-symmetric and rounded features can be added to the square part because the tool can rotate in multiple ways. You can even add compound angles to standard drilled and tapped holes.
A lot of times, tolerances will become tighter with CNC machines that have more axes. This further improves how complicated you can design a part to be, with the understanding that it will still work in your application and fit in your assembly.
Allows for More Hands-Off Machining
Much automation comes in a standard 3-axis CNC machine. The downside is that the machinist will have to change the orientation of the part and might have to spend time setting up the angle of the head to make complicated features.
With 4-axis and especially 5-axis CNC machines, it’s more hands-off. Since the heads can move around freely and more than a standard machine, it’s common for a machinist to set up the program and let the machine do the rest of the work.
With foresight into how to hold the part before starting the cut, it’s possible that the machinist doesn’t need to re-orient the part at all.
Machining Is Often Expedited
How quickly the project gets done depends on how many axes are added. CNC options are still dramatically faster than manual milling, but 5-axis tools usually finish projects faster than 3-axis ones.
This has to do with the faster operation, less need for machinist intervention, and the ability to make complex features without additional setup.
Challenges in Finding the Right Shop
You’ll need to do some research if you want to use a 4-axis or 5-axis machine for your upcoming project. Finding a shop that offers these more complicated CNC machines is more difficult than you might think.
Smaller shops might only have 3-axis CNC machines on their floor. Alternatively, their 5-axis tools might only be reserved for their top customers who have the largest orders.
Added Cost for Premium Services
Some machine shops charge more for using their 4-axis and 5-axis CNC machines. This might be considered a premium offering for a shop, so it makes sense that the price is higher. Not to mention these tools cost significantly more than a standard 3-axis mill.
Make sure you reach out to the shop ahead of time to get a budgetary quote before deciding which shop is right for you. Ideally, you would find a shop that offers 5-axis CNC machining without charging you extra or forcing you to place a massive order.
Conclusion
We just covered everything you need to know about 3-axis, 4-axis, and 5-axis CNC machines, along with which option is right for you. 5-axis machines are more expensive and a little tougher to find, but they offer the fastest turnaround times and can handle the most complex parts.
At Rapid Axis, we have a number of 3-axis, 4-axis, and 5-axis CNC machines to handle your projects. We don’t charge a premium upcharge or make it inconvenient for you. Reach out to us today to get a free quote or chat with one of our expert machinists.