By using 3D printing, companies can make a physical object from a three-dimensional digital model by laying down many thin layers of a material in succession in the multilayer environment that 3D modelling software provides. This process is also referred to as additive manufacturing (AM), a term which attempts to describe the layer-by-layer digital build of an object that is ultimately rendered into a physical form.

3D printing has been used successfully in manufacturing relatively small objects that require high levels of customisation such as hearing aids and dental titanium implants. The process saves time in design, enables rapid prototyping and checkout of experimental designs, and gives companies advance visibility of potential design problems before these problems physically manifest themselves in production and are exponentially costlier to correct. One by one, 3D printing success stories are growing. In the hearing aid market alone, over 10 million people worldwide are now using 3D printed hearing aids.

Now, examples in the electronics market are emerging. For example, in one case, 3D printing was used to produce a solderless 1/16inch circuit board containing a simple microcontroller circuit that flashes three LEDs in sequence, the circuit board is designed and printed on a PolyLactic Acid (PLA) thermoplastic filament printer, trace channels are filled with a commercial conductive paint that is highly conductive, and the result is a working circuit board that is not as vibration resistant as a soldered circuit board, but that can be quite useful for experimental circuits and prototypes.

At first glance, this might seem simplistic, and even just a demonstrative approach to 3D printing techniques in electronics manufacture. However, the reality is that three-dimensional (3D) additive manufacturing techniques have already been utilised to make 3D electrical components like resistors, capacitors, inductors, circuits, and passive wireless sensors.

In their work at the University of California at Berkeley, Doctors Shen Yang and Sung-Yueh Wu used fused deposition modelling technology and a multiple-nozzle printing system with a printing resolution of 30μm to construct 3D supporting and sacrificial structures for a prototypical integrated circuit that would be used for passive wireless sensors. The scientists then removed the sacrificial materials from the circuit they were constructing, and injected suspensions of silver particles to form metallic interconnect elements. The resulting integrated circuit prototype showed good characteristics of fabricated 3D microelectronics components.

“This work establishes an innovative approach to construct arbitrary 3D systems with embedded electrical structures as integrated circuitry for various applications, including the demonstrated passive wireless sensors,” reported the scientists. “We propose to use regular 3D printing equipment to construct 3D microstructures with embedded metallic elements by means of fillings of liquid metal paste to produce a variety of basic microelectronics components, such as resistors, capacitors, and inductors… By connecting these basic components, one can build more complicated circuitries as well as numerous functional systems.”

Already there are commercialisation efforts underway for 3D printing of electronics circuit boards and components. At the same time, 3D printing is still a nascent technology that must overcome its share of hurdles before use in electronics expands.

“The key challenge in 3D printing electronics is developing material suitable to be used in a desktop 3D printer,” said Dr. Elena Polyakova of Graphene 3D Lab.“To do this, you must incorporate conductive material (such as graphene) with a standard 3D printing material, but not so much that the filament loses processability. The advantages of 3D printing are that it has the ability to truly integrate electronics with objects, and the fact that 3D printing allows for distributed manufacturing,” Polyakova added.

Another key hurdle for 3D printing is equalling the reliability levels that 2D electronics fabrication delivers, given the over 10 years of in-production use that have perfected 2D techniques.

Despite these hurdles, however, even as reliability, repeatability, speed, and yield issues remain with 3D electronics printing, 3D printing should be on the technology roadmaps of electronics manufacturers because of its potential to provide an agile approach to the more complex geometries and materials that are likely to be required for electronics in future advanced manufacturing environments.

"When we use it [3D printing], we can print at different angles and conform it the way we want," said Dale Kurita, a senior electronics technologist at Lawrence Livermore National Laboratory. "There's just unlimited capabilities in the future. This opens up a whole new door for people to look at electronics differently.”

First published on EBN.