Difference Between 3-Axis 4-Axis And 5-Axis Milling
CNC milling machines come in many configurations. Among the most common options are the 3-axis, 4-axis and 5-axis.
The type of machine to go for will depending on your material fabrication capability. This guide explores some fundamental aspects you can consider when choosing these milling machines
Even before exploring the difference between 3-axis CNC mills, 4-axis CNC mills, and 5-axis CNC mills in detail, let us be clear about one thing.
The difference between these CNC milling machines is mainly in the degree of motion. That is the number of directions and cutting capabilities the tooling system can achieve during any machining process.
For you to understand this clearly, we will start with the basics as we advance to slightly more complex scenarios:
Difference between 3 Axis and 4 Axis CNC
| Variable to Compare | 3-axis CNC Milling Machine | 4-axis CNC Milling Machine |
| Number of axis | · X, Y, and Z · X – movement in the vertical direction · Y – movement in the horizontal direction · Z – represents up and down movement | · X, Y, Z, and A (3-axis plus 1 axis) · A-axis |
| Degree of motion | · 3 linear degrees of motion | · Works in X, Y, and Z, alongside a rotary motion along X due to A-axis |
Additionally, 4-axis CNC milling machines come in:
- Indexing type of 4-axis CNC machine
- Simultaneous type of 4-axis CNC machine
Ideally, the table of 3-axis vs. 4-axis simply explains these CNC milling machines working principle. Now, let’s move a step further to compare the next types of CNC milling machines.
Differences between 4 Axis and 5 Axis CNC
| Variable to Compare | 4-axis CNC Milling Machine | 5-axis CNC Milling Machine |
| Number of axis | · X, Y, Z and A (3 plus 1 or 3 plus A) | · X, Y, and Z, plus the B and C axis · Depending on the type of CNC Machine, they may use A-axis |
| Degree of motion | · Operated in X, Y, and Z axis, while adding degree of rotation for the workpiece along the X axis. Rotary motion is due to the extra A-axis. | · Complex degree of motion which may include B-axis and C-axis rotation or A-axis and C-axis rotation · The above degree of motion works alongside the X, Y, and Z. |
In addition to the above information, it is important to note that the 5-axis CNC milling machines are available as:
- Index 3 + 2 axis
- Continuous axis
With the working principle of 4 axis vs. 5 axis now evident, let’s move a step further to explore other differences.
In this second segment, we shall focus on the cost and complexity of CNC milling operations. Remember, depending on the part you wish to machine, you can choose a 3-axis, 4-axis, or 5-axis machine.
Again, let’s summarize this in the table below:
| Variables to Compare | 3-axis CNC Mill | 4-axis CNC Mill | 5-axis CNC Mill |
| Cutting capability | · Cuts parts in 3 axes (X, Y & Z) | · In addition to the 3 axes, the rotary motion allows for cutting complex geometries such as helixes, arcs, angled configurations, etc. | · Both spindle and workpiece rotate in a 5-axis CNC milling machine · Cuts workpiece in XYZ and rotation in A and C or B and C |
| Benefits | · Cost-effective for machining parts with simple geometries · Machine setup time is shorter and easy to operate · Easier to program | · More feasible and economical for complex parts than 3-axis CNC · Can maintain tight tolerances since you will not change fixtures during machining. · 4th axis helps to cut holes | · Machines all 5 sides of the workpiece at the same time · Can machine parts with complex geometry · Can machine parts that could otherwise be fabricated using molds |
| Limitations | · Not suitable for unconventional shapes (Cannot machine complex parts) · May not machine deep and cavities well · Low production speed and precision · Limited capability | · Programming is a little challenging compared to a 3-axis milling machine · Limited speed · High machining costs | · Programming machine is slightly more difficult than the 3-axis CNC machine and 4-axis CNC machines · Require advanced operator training · Costly machines |
So, which CNC milling machine should you use?
Your decision will depend on:
- Geometrical shape of the part you want to mill (simple or complex)
- Production volume
- Budget
- Tolerance
Axes of Operations for CNC Machining
In our last segment, let’s put the working principle, and part finishes of the 3-axis, 4-axis, and 5-axis CNC milling machine into perspective:
| Nature of Operation during CNC Milling Process | Recommended CNC Milling Machine Based on Axis |
| Degree of movement | · 3-axis: Low degree of movement · 4-axis: Medium degree of movement · 5-axis: Highest degree of movement |
| Part complexity | · 3-axis: Less complex geometries · 4-axis: Medium to less complex parts · 5-axis: Highly complex geometrical parts (It may substitute molding in certain applications) |
| Positioning | · 3-axis: Limited positioning · 4-axis: moderate positioning · 5-axis: More options for positioning |
| Machining time | · 5-axis faster due to multiple tooling than the x-axis |
| Programming | · The 3-axis has the simplest programming followed by the 4-axis then the 5-axis machines · The level of training personnel will also follow the same order |
| Degree of machined part customization | · You can achieve the highest degree of customization with the 5-axis CNC milling machine, followed by the 4-axis CNC milling machine then the 3-axis CNC milling machine |
| Finishing | · The 5-axis provides the highest degree of finishing hence fewer secondary operations. |
| Tooling system management | · Tooling collision is less in the 4-axis and 3-axis due to the low degree of movement · With many degrees of movement, tooling collision may occur in the 5-axis especially if there problem with the programming · In most cases, the 4-axis and 5-axis machines use shorter tools, unlike the 3-axis. Therefore, there is a low chance of tool breaking in a 5-axis machine. |
At TSINFA, we offer a wide range of CNC milling machines with varying degrees of motion.
For simple machining tasks, you can choose a 3-axis milling machine. However, for moderately complex machines, a 4-axis milling will work for you. But if you must make very complex components, then the best choice will be a 5-axis milling machine.
Remember, the number of axes simply implies the complexity of the milling process.
Simply tell us your machining needs and our technicians will advise you accordingly – contact us.
More resources:
Axis in CNC Milling Machine – Source: NED
Milling Machine Buying Guide – Source: TSINFA
