3 axis or 5 axle milling: Which processing fits the component?
More axes do not automatically mean better processing. The decisive factor is which geometries are to be manufactured, how many pages must be accessible and which effort is economically useful in clamping, programming and equipping.
Many prismatic components can be processed quickly and precisely on a 3 axis CNC milling machine. As soon as several processing pages, sloping surfaces or hard-to-reach contours are added, two additional round axes can offer advantages. In between is the so-called 3+2 machining, in which the workpiece is first positioned and then machined with three linear axes.
In this article we explain the differences between 3 axis, 3+2 and simultaneous 5 axis processing. We also show why a flexible machine configuration with an additional swivel table can be interesting for changing tasks.
What does 3 axis milling mean
In a 3-axis CNC milling machine, the tool moves relative to the workpiece along the three linear axes X, Y and Z. This can be used to produce, among other things, flat surfaces, pockets, bores, grooves, contours and many three-dimensional shapes.
The processing is usually done from an accessible page. If further sides need to be processed, the workpiece is re-tensioned or positioned in a different position. For many components, this is completely sufficient and economically sensible.
Typical advantages of 3 axis machining
Comparatively simple programming
Clear tool paths
Short preparation for simple components
Good accessibility with prismatic geometries
Economic processing of individual parts, prototypes and small series
Free use of the machine table for vices, devices or larger workpieces
Especially with components that are predominantly processed from above, an additional round axis does not automatically bring added value. In such cases, a clean 3 axis strategy can be the simpler and more productive solution.
When are three axes no longer enough?
The limits of a 3-axis machining are especially apparent when the tool cannot reach certain surfaces from a fixed direction. Typical examples are lateral holes, sloping surfaces, several machining pages or complex contours.
Although the workpiece can be re-tensioned several times, each additional clamping process requires time. In addition, the new workpiece position must be clearly determined again. Depending on the component, device and accuracy requirement, this may result in additional deviations.
Additional circular axes are therefore particularly interesting if:
Several sides of a workpiece are to be processed
Frequent manual tensioning should be avoided
Oblique holes or surfaces are required
Short tools can be used by a cheaper employment
Complex contours should be more accessible
The position relationship of several machining surfaces is particularly important
However, whether the additional technical effort is worthwhile always depends on the specific component spectrum.
What is a 3+2 axis machining?
In the 3+2 machining, the workpiece is brought into a defined position with the help of two round axes. During the subsequent milling machining, these round axes remain in place. The actual processing takes place via X, Y and Z.
This approach is also referred to as employee or positioned processing. It is suitable, for example, for several workpiece sides, oblique boreholes and surfaces that are machined from different fixed directions.
The main advantage is that several machining situations can be achieved within a clamping. This can reduce set-up processes and improve the assignment of the processed surfaces to each other.
3+2 axes are therefore not simply an interim solution. For many workpieces, this strategy is already the technically and economically appropriate answer.
What is the difference between simultaneous 5 axis processing?
In the case of simultaneous 5-axis machining, the three linear axes and two round axes can be moved in a coordinated manner during the milling process. As a result, the tool orientation can be changed during processing.
This is particularly interesting for freeform surfaces, complex transitions and hard-to-reach contours. At the same time, however, the requirements for machine, control, CAM programming, simulation and process understanding are increasing.
Simultaneous movement is therefore not necessary for every component. It is not crucial to move as many axes as possible at the same time, but to choose the processing path that combines quality, process reliability and profitability in a meaningful way.
3 Achs, 3+2 oder simultan: ein direkter Vergleich
Criterion | 3 axis | 3+2 axle | Simultaneous 5 axis machining |
Moving axes during milling | X, Y, Z | X, Y, Z by positioning | Linear axes and round axes coordinated |
Typical components | Bags, contours, drilling patterns, simple 3D shapes | Several sides, sloping surfaces, employed holes | Freeform surfaces and complex geometries |
Encompass | Depending on the number of pages more often | Often reducible | Often highly reducible |
CAM effort | Comparatively low | Means | Higher |
Space on the machine table | Largely freely usable | Limited by swivel table | Limited by swivel table |
Economic use | Simple to medium geometries | Multi-page editing | Complex, sophisticated components |
The table shows: No variant is fundamentally superior. The best economic solution results from workpiece, batch size, tolerances, processing time and available programming competence.
Why a removable swivel table can be interesting
In many companies, the parts spectrum is changing. Today simple plates, housings or fixture parts are manufactured, tomorrow a workpiece with several machining sides. A permanently fixed machine configuration therefore does not always fit all tasks.
An additional, removable swivel table can create flexibility here. For classic 3-axle work, the workspace remains usable for vice, clamping plate or individual devices. If additional machining directions are required, the machine can be expanded or configured accordingly.
Technical points such as installation space, load capacity, interference contours, accuracy, zero point, control and CAM process must be taken into account from the beginning. The advantage lies not only in two additional axes, but in the possibility of adapting the machine more specifically to changing tasks.
Practical example: A compact aluminum demo part
The images show the processing of a small aluminum demo part in the vice. The example makes an important point visible: Even if additional round axes are present or prepared in a machine, not every component has to be machined on a five-axis.
For the voltage shown, accessibility, safe tension and clear tool access are the focus. Which processing strategy is suitable is already determined before the first chip. These include, among others:
Check geometry and editing pages
Specify suitable tensioning
Check tool accessibility and possible fault contours
Plan editing order
Select tool and cut dates
Simulate the program and then drive in a controlled manner
The existing axis circumference should therefore not determine the processing strategy. Conversely, the strategy must arise from the actual requirements of the component.
For speed, feed, machining thickness, time span volume, cutting force, power and torque, the free CNC cutting data calculator from ABEL Technologies can be used in addition.
Which processing strategy makes economic sense?
A decision should not be made solely on the basis of the complexity of the component. Number of pieces, repeat parts, set-up time, required tolerances and available CAM knowledge also play a role.
A 3 axis machining is often useful when:
The workpiece is mainly accessible from one side
Only a few additional tensionings are required
Simple or prismatic geometries dominate
Fast and clear programming is important
The table space is to be used flexibly
A 3+2 processing is often useful if:
Several workpiece sides should be achievable in one tensioning
Inclined surfaces or holes are provided
Overload operations are to be reduced
Fixed angles are sufficient for processing
A simultaneous 5 axis machining is particularly suitable if:
The tool orientation must be changed during milling
Complex freeform surfaces can be processed
Contours with permanent employment are not sufficiently accessible
The geometry requires a coordinated sequence of movement of all axes
Before making an investment decision, not only the maximum number of axles should therefore be considered. A selection of typical workpieces is more meaningful, on the basis of which the processing strategy, working space, clamping concept, tools and CAM process can be assessed.
Flexible CNC solutions for different components
A compact 3-axis CNC milling machine offers an economic basis for classic machining tasks with freely usable machine table.
The MPS 3m combines a compact machine design with different configuration options. When complex geometries and several machining pages are the focus, a compact 5 axis CNC milling machine such as the MPS 5m can be the right solution.
Regardless of the axle configuration, tool, material and machining strategy must be coordinated. How speed, feed, machining thickness, power and torque are related, we explain in the technical article Calculating cutting data for CNC milling.
The following questions are relevant for the selection:
Which materials should be processed?
How big and heavy are the typical workpieces?
Which editing pages must be accessible?
Which spindle speeds and tools are required?
How often do components and tensionings change?
Is positioned or simultaneously processed five-axis?
On this basis, it is possible to assess which machine configuration fits the actual application.
Result
3 axis and 5 axis processing are not direct opposites. Many components can be manufactured three-axle efficiently and precisely. Additional round axes bring their advantages where several sides, sloping surfaces or complex contours need to be accessible.
A flexible machine configuration can be particularly interesting when the parts spectrum changes and both classic 3-axis tasks and multi-page machining are provided. However, the component always remains decisive. Only this results in the appropriate tensioning, axis configuration and machining strategy.
Would you like to compare different components or machine configurations? Please send us some information about material, dimensions, weight, geometry and desired processing. On this basis, we can narrow down the basically suitable configuration together.
Frequently asked questions
What is the difference between 3 axis and 5 axle milling?
In the case of 3-axis milling, the machining is carried out via the three linear axes X, Y and Z. A 5-axis machine additionally has two round axes with which the workpiece or tool can be positioned from further directions or moved during machining.
When is a 5 axis machining worthwhile?
It can be worthwhile if several workpiece sides, sloping surfaces, hard-to-reach contours or complex free-form surfaces have to be processed. Whether it is economical also depends on the number of pieces, set-up time, tolerances and programming effort.
What does 3+2 axis machining mean?
In the 3+2 machining, two round axes position the workpiece in a fixed position. During the subsequent milling processing they remain and the processing takes place via X, Y and Z.
Is 5 axis milling always more accurate than 3 axis milling?
No. The achievable accuracy depends, among other things, on machine structure, kinematics, measuring systems, tensioning, tools, temperature, programming and process management. More axes do not automatically mean higher accuracy.
Can a 3 axis CNC milling machine be extended with a circular swivel table?
This depends on the machine concept, control, working space, interfaces and planned kinematics. With an appropriately designed machine, an additional swivel table can be a flexible addition to positioned or five-axle tasks.
What information is required for the selection of a CNC machine?
Material, maximum dimensions and weight, typical geometries, tolerances, desired surfaces, quantities, tools, spindle requirements and the required machining pages are helpful.
