Industrial 3D printing has opened up new possibilities in part manufacturing: it can be used to produce test pieces quickly, as well as components with complex geometries that are difficult or impossible to manufacture with conventional machining. At the same time, this does not reduce the importance of CNC machining. In fact, in many cases, combining the two technologies provides the best solution. In this article, we have collected when it is worth using each technology.
3D printing or CNC machining
The advantage of industrial 3D printing is that it can be used to quickly produce a part that can be handled and tested. This is especially useful when fit still needs to be checked, multiple versions need to be compared, or the decision should be made based on actual installation rather than a drawing.
At the same time, CNC machining is still the better choice in many cases when accuracy, ease of assembly, material properties, durability and reliable operation are the decisive factors.
When is industrial 3D printing a good decision?
Industrial 3D printing is most useful when a physically testable part is needed quickly.
This may be a prototype, an assembly test or the quick comparison of several different designs. In such cases, the goal is not necessarily final part manufacturing, but to find out as quickly as possible whether the concept works in practice.
Industrial 3D printing is especially useful when:
- a rapid prototype is needed,
- several versions need to be tested within a short time,
- fit or ease of assembly needs to be checked,
- the part has complex geometry,
- a custom production support element needs to be produced quickly.
3D printing can also be a good choice when the part geometry is complex, or in the case of built-in elements that could only be produced with conventional machining with compromises or disproportionate cost.
It also has a practical advantage in production support: for the quick replacement of custom fixtures, inspection templates, fitting elements, guide elements or protective elements, 3D printing can provide a usable solution with a short lead time.
When is CNC machining the better choice?
If the part is no longer made for testing, but for longer-term operational use, CNC machining is often the better decision. This is especially true when high accuracy, clearly defined tolerances, reliable ease of assembly and long-term reliable operation matter, not just whether the part matches the required dimensions.
CNC machining is generally the better choice when:
- a final part is being made,
- accurate dimensional stability is important,
- tolerances and fits are critical,
- the part is subject to load,
- durability and repeatable quality are expected.
CNC also has a significant advantage when the following matter:
- material selection,
- critical surfaces,
- fit with mating parts,
- long-term load capacity.
In these cases, the quality of the final part depends not only on its shape, but also on the operation sequence, tolerances, material and inspection.
Combined use of 3D printing and CNC machining
In practice, the question is often not whether to use 3D printing or CNC machining, but how the two can best complement each other.
A typical, well-functioning 3D printing and CNC machining process:
- Creation of a 3D printed test part.
- Checking fit and ease of assembly.
- Making the necessary modifications.
- Manufacturing the final part with CNC machining.
Using the two technologies together can save time, unnecessary rounds and, in many cases, cost as well. If an error or need for modification is identified already at the prototype stage, final manufacturing can start with much greater confidence.
What should you consider during 3D printing?
In industrial 3D printing, the model itself is not enough. The following must also be considered:
- what the part needs to withstand,
- where it comes into contact with other elements,
- which dimensions are critical,
- what environment it will operate in.
Good design is also the basis of a good result here. Special attention should be paid to the fact that the dimensions of 3D printed holes and fits may differ from the nominal size. For this reason, in many cases it is worth designing with machining allowance and, if needed, allowing for post-machining.
Engineering design, 3D printing and CNC machining with an engineering mindset
Whether it is 3D printing or CNC machining, the most important thing is always that our customers receive exactly the part and quality they need. We also help select the right technology and optimise costs.