3D printing or CNC technology: Which process for which purpose?

3D printing technology has permanently revolutionised the way we manufacture and is increasingly being used instead of machining processes or injection moulding technologies, most notably in automotive engineering, aerospace and medical technology. But does additive manufacturing also have the potential to displace CNC machining, or is it rather a useful complement to CNC technology? In the following, we will examine the advantages and disadvantages of both methods and show you when they are best used.

Additive manufacturing: cost-effective, flexible & sustainable

3D printing is known for its great design freedom and can realise even complex geometries quickly and cost-effectively. Therefore, this process is particularly suitable for the production of prototypes and is especially popular in research and development departments. Changes to the geometry of the construction can be made in just a few simple steps and the components can be manufactured efficiently with little effort. Compared to CNC machines, 3D printers are quick to set up, as clamping tools are no longer required and they can be operated by a designer instead of a trained skilled worker. The absence of coolants and the low material waste also speak in favour of 3D printing and ensure a sustainable manufacturing process. This also reduces the costs for storing raw materials and the chips that are produced do not have to be disposed of at great expense.    

CNC technology: high production speed with precise, stable results

Despite the numerous advantages of additive manufacturing technologies, this process also has its limits and can only partially replace CNC machining. For example, if the focus is on precision, the CNC machine tool is still superior to the 3D printer, because the latter does not work quite as precisely, with an average accuracy of +/- 0.05 mm. In addition, the components produced by 3D printing do not have the same surface finish as components produced with a CNC machine, and desired surface structures cannot be produced as easily. Since additive processes create components layer by layer, they are often less strong and stable than parts that have been machined from a solid block of metal, for example.

Combining both technologies

Whether conventional CNC machining or modern 3D printing technology is used depends on many factors. Therefore, additive manufacturing should be seen less as a replacement for CNC technology and more as a useful supplement with which you can manufacture components quickly, cost-effectively and sustainably, depending on your requirements. Often, both processes are even combined, for example when printed objects are reinforced with traditionally manufactured parts at points subject to higher mechanical loads. Or printed parts are machined to ensure critical tolerances or required surface finishes. CNC machining centers are already in use, which can be converted into a 3D printer in no time at all using a 3D print head, thus combining both technologies in a single machine. The OPTImill 5X 3D print head, for example, can be used to expand CNC milling machines from Optimum or comparable machines with Siemens controls.