The field of 3D-printed electronics, or additively manufactured electronics (AME) is rapidly evolving, with innovative processes continually expanding the range of possibilities for various applications. What all these emerging processes have in common is that they enable higher levels of freedom in designing electronic devices than conventional methods offer. This is achieved through additive processes, during which the structures are built up layer by layer. This allows for placing conductive structures in the surrounding matrix with a high level of flexibility.

Since understanding the properties and limitations of printers and materials is crucial for achieving optimal performance, this article aims to give a brief overview of different AME-manufacturing approaches. The processes presented here include inkjet-, filament-based printing, as well as dispensing-like and full metallization schemes of 3D-printed polymers. A second objective is to shed some light on the benefits that come with this new technology.

Inkjet-based AME printers can process conductive and insulating inks simultaneously. This leads to a high degree of freedom in the design, as each individual voxel can be set to be conductive or insulating. It is thus possible to freely shape the form factor of conductive traces embedded in the insulating substrate. Typical resolutions of conductive traces are in the range of 80-400 µm. The utilized conductive and insulating materials need to be compatible, which currently limits the variety of suitable materials. The current available material systems include polymers and ceramics as dielectrics and silver as conductive material.

In contrast to inkjet-based systems, filament-based systems are much more flexible in terms of available material systems. As the name suggests, the creation of dielectric structures is based on filament 3D-printing, which automatically gives access to many different materials. To increase the surface quality, these AME printers often contain milling tools to smooth the 3D-printed structures. The incorporation of conductive materials is usually achieved by dispensing or aerosol jet print heads. Other possibilities include the direct embedding of copper wires into previously printed cavities. While these ways of incorporating conductive material limit the flexibility of the achievable traces, the form factor of the dielectric substrate can be chosen freely.

Dispensing-like systems are not only available in the filament-based systems described above, but also exist as stand-alone systems. While their main purpose is to place conductive materials, some of them are also able to process insulating ink. However, both inks are processed separately and need manual interference if the ink is switched. Different technologies are available in this technology class, i.e., micro-dispensing, aerosol jet printing and capillary-based printing. All these processes stand out for achieving very fine resolutions, some even in the range of several hundred nanometers, like the capillary-based approach. The other technologies can realize line widths in the micron range as well. Due to their high resolution, this category of processes is not suitable to build up whole devices but is usually combined with other processes that allow for a faster realization of larger structures.

If the goal is to not only add single conductive traces but to add a conductive layer to larger areas or to complete bodies, metallization approaches are more suitable. These processes allow the metallization of complete 3D-printed polymer bodies. Due to the smooth surfaces and the high resolution that can be achieved with modern polymer printers, these processes are often used for RF applications. Besides the metallization of full bodies, the possibility to partially metallize parts is limited.

After presenting different types of AME processes, the question of the benefits remains open. As already mentioned earlier, the main difference compared to traditional electronic manufacturing technologies is the flexibility in the shape of the conductive structures. In the next article we will go into details of the advantages of this additional design flexibility from different fields of electronics. If you’re interested in learning more about AME and its potential, be sure to check out our website for more insights and resources.