3D modeling and printing of circuits could revolutionize electronics but challenges remain.
The advent of printed circuit boards (PCBs) in the 1950s revolutionized electronics. Gone were the days of painstakingly soldering circuit components by hand, point to point. A new era of automation was born that dramatically increased production rates and circuit reliability. Fast forward nearly a century and by all indications, additively manufactured electronics (AME) is poised to cause a similar disruption in the 21st century.
As the name indicates, AME is an emerging technology that leverages additive manufacturing to create electronic components. Although this general idea is quite simple, its implications are vast.
Printed, but Not 3D Printed
A PCB begins its life as a block of clean substrate. Copper is applied to this entire substrate and then removed in areas using a variety of processes including etching and milling to create the conductive path. Electronic components can then be soldered, manually or automatically, in their designated spots on this outline.
High-end applications sometimes require multiple PCB layers. In these cases, sticky resin is used to attach multiple PCBs together. Each board contains an independent circuit, so to establish interconnectivity, a hole, or “via,” is drilled through the boards. The via is then metallized or coated in conductive material so it can carry electrical signals from one layer to the next.
Multilayered PCBs are essential to avoid sprawling, wasteful circuit designs but vias incur a substantial cost on the fidelity of the signal. When an electrical signal travels between layers, it faces a change in impedance between the trace on one layer and the via structure and then again between the via structure and the trace on the other layer. These impedance changes can cause a host of problems, such as signal reflection and electromagnetic interference.
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A New Dimension
AME does away with the board paradigm entirely. Using nanoscale 3D inkjet printers, AME uses conductive and nonconductive ink to create both the housing and conductive outlines of a circuit. And because the process is additive rather than subtractive, AME can create smooth three-dimensional pathways that would be impossible to create using conventional subtractive methods. AME circuits sort of look like miniature cities straight out of the “Tron” franchise.
AME’s tremendous potential extends beyond its futuristic aesthetic. With the ability to print both conductive and nonconductive materials within the same 3D printing system, AME can create three-dimensional circuits that are directly embedded into their housing. This enables designers to utilize space much more efficiently than would be possible with flat PCBs, leading to tantalizing miniaturization potential. Printing the entire system in one go also means that less assembly is required and eliminating the conventional subtractive manufacturing process makes the circuits less wasteful and more environmentally friendly. Think of all the copper that will no longer be lost to etching.
That’s not all. With the ability to create 3D coaxial lines, vias become almost entirely redundant. This will lead to improved signal fidelity because impedance mismatches are no longer an issue. AME also reduces the need for connectors and cables. With 3D coaxial cables in your toolkit, electrical signals can flow from one functionality to the next within shielded coaxial cables. This allows signal-carrying lines to be brought closer together without fear of interference and crosstalk, leading to even more space efficiency.
If miniaturization is the name of the game in electronics—and it most certainly is—you can see how the buzz around AME is warranted.
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Designing for AME
So, what does the design process for AME look like? Rolf Baltes, head of Engineering at J.A.M.E.S (Jetted Additively Manufactured Electronics Sources), recently summarized the design flow at the conference 3DEXPERIENCE World 2023.
First, he described the conventional PCB design process, which begins by simply creating a list of all the circuit’s electronic requirements, that is, what the circuit will need to accomplish. The designer can then use this list to create a schematic, which provides an overview of all the circuit’s required components and the connections between them. Next, this circuit diagram is converted into “footprints,” where symbols on the schematic are changed into drawings of actual circuit components. This introduces information about the dimensions and physical location of the components. Finally, footprints are changed into a circuit layout, which fills in the gaps with information about connectors, cables, vias and so on.
AME design flow looks very similar early on. “The schematic is the same,” says Baltes. “We also need the information at the footprint.” But the design flows diverge drastically here. Instead of using the footprints to generate a layout, AME requires conventional footprints to be converted to 3D footprints. J.A.M.E.S. engineers currently use DXF or ODB++ to generate these 3D footprints and to begin mapping out wiring. At this stage, you may need to add additional 3D electronic components such as antennas, capacitors or coils because these are not typically included in a conventional layout.
Critically, the creation of 3D footprints must consider the mechanical requirements of the system because the circuit and its housing will be printed simultaneously. The mechanical design of the system must go together with the electronic design and AMEs are an interdisciplinary venture by nature. The design process is a juggling act with factors like heat dissipation, electrical conductivity and structural integrity all up in the air.
Finally, the mechanical design and 3D footprints are combined in, say, SOLIDWORKS, and 3D connections between all circuit pads are created. The result is a computer design that incorporates both the mechanical and electronic structures into one.
Fresh Challenges and How to Overcome Them
Like all emerging technologies, AME has its growing pains. Many of the challenges are common to additive manufacturing in general. For starters, the available range of conductive materials suitable for 3D printing is still relatively narrow. Determining ideal process parameters is still an arduous task because there are no established norms. Market inertia means that environmental tests and qualifications are slow to be established. The technology is not yet scalable to mass production—something that general additive manufacturing processes still struggle with. And, of course, accessibility remains an issue, with only the most well-off researchers and organizations able to secure the required tech for AME research and development.
Baltes believes that the key to overcoming these challenges is to build up a collaborative online community that would in essence “crowdsource” the development of AME. Establishing and maintaining this online community is the primary directive of J.A.M.E.S. Its growing AME community currently features AME periodicals, technical documents and forums. “A big part of our platform right now is education,”, says Baltes and a big part of education is connecting experts and enthusiasts across the world. This will accelerate the development of process parameter standards, environmental tests and so on as the whole community will be able to benefit from every trial and experiment. Soon, the platform will also feature printer services to improve accessibility. Researchers will be able to upload their designs to the platform and request quotations from printer service providers, enabling folks to explore the technology without taking a major financial plunge. This AME community is located at https://j-ames.com/partners/partners/community. There’s even a fledgling subreddit you can check out at https://www.reddit.com/r/AMElectronics/.
If you are an electronics expert, entrepreneur, or just a tech afficionado, you can bet this won’t be the last you hear of AME. Its prospects are simply too tantalizing and are sure to overcome its challenges.
