IoT and 3D printing might look like the greatest marriage of two buzzwords in the history of tech. The internet of things, after all, unlike the internet of applications and data, takes up 3D space and uses physical materials, including the electronics that control devices and carry their data home. The ability of 3D printers to produce one-offs from CAD designs cheaply and quickly promotes experimentation and is therefore a boon to designers. It should not surprise, then, that in the past few years we've begun to see the convergence of IoT and 3D printing, with 3D printing applied to the prototyping and even manufacturing of circuitry and printed circuit boards, much of it for IoT devices.
The term "3D" is used loosely in this context. Good old 2D laser printers have been used by hobbyists to print flat circuit designs. These prints, transferred to a blank, copper-clad FR4 (flame-resistant fiberglass) board, make the mask that shields the copper from the "etching" acid bath that eats away all the unshielded copper in between your circuit's conductive traces. Most of the "3D" board prototyping printers now available or in development are actually printing 2D lines of conductive ink -- i.e., traces -- in 3D space, using printheads that can be directed along X, Y and Z axes.
Additive vs. subtractive manufacture
It's the ex nihilo, additive quality of 3D printing that's important here. (Etching baths and CNC milling machines, another prototyping approach, are subtractive.) You start with naked fiberglass or flexible board. The only metal making traces in this process is the typically silver nano particulates in the ink being aerosol- or inkjet-printed from the 3D printer's nozzle, just like thermoplastic is 3D printed, layer upon layer, out of nothing, to make 3D solid shapes like prostheses or water pistols.
When 3D circuit board printing develops to production-level, this will save the industry from a lot of the hazardous etching chemicals -- as well as copper coating -- it uses today. But we're not there yet. Dean Freeman, Gartner's vice president of research on semiconductor manufacturing and process development, thinks we're at least five years away.
In terms of current users, 3D printing of PCBs today is generally done in research labs in enterprises and universities, defense industries, and among bleeding-edge, experimental electronics designers. Many of these users are now designing boards for riskier project ideas than they otherwise could, simply because an in-house DIY prototyping machine saves them serious time and money.
For now, quicker turnaround and cheaper production are the two biggest benefits of 3D printers to PCB designers. They can turn a multi-week, $500 process involving a third-party prototype maker, often in Asia, into hours. Designers say that by eliminating third parties, they cut off an avenue to IP theft and reduce the risk of miscommunication. And with relatively tiny initial investment, 3D printers allow engineers to prototype more unproven ideas, a benefit of enormous value to IoT invention.
Ted Vaida is the designer of embedded electronics and founder of Exact Assembly in Colorado Springs, Colo. He has one of the 100 Squink 3D printers sold so far by BotFactory, a startup in a business incubator space in Long Island City, Queens, N.Y. Although it may not be Vaida's biggest project, he is literally helping an inventor build a better mousetrap.
IoT and 3D printing: It's all about the speed and value of data
It's not the trap part Vaida cares about; it's the sensor and reporting electronics that alert you to the presence of a dead mouse. If this sounds like too much solution for too little problem, consider restaurateurs, hoteliers or home sellers who have set mouse traps. Wouldn't they want to be the first to know?
"If you want to make 10 dozen mousetraps and give them out to potential alpha customers to get feedback, you need a quick way to create something that's very much like your final product," Vaida said. "I've got small, low-complexity designs we can do right now." And he's prodding JF Brandon, vice president of sales and marketing, and Carlos Tarazona, CTO, both at BotFactory, to improve Squink's speed and resolution to achieve the same low-cost, low-volume and fast-iteration prototypes for his higher-end, enterprise projects.
As things now stand, designers only achieve economies of scale once they commit to thousands of boards. The sticker shock of design and prototyping scares investors off, and "IoT wants to do very rapid prototyping and development," Vaida said, as the race to market is swift.
The desktop-sized Squink sells for $3,999 for printing two-layer boards, $3,199 for one. It not only prints traces; with another printhead it also automates the "pick and place" part of the PCB build -- the mounting and even soldering of chips and other surface-mount devices onto the board. As such, it uniquely automates everything between CAD design -- reading traditional PCB design files -- and finished board.
BotFactory also stands out for printing on rigid or flexible substrate. Zebra Technologies is using Squink to prototype RFID tags.
The only PCB printer truly working in 3D today, Gartner's Freeman said, is the DragonFly 2020, made by Israeli company Nano Dimension. Although it too fits on a desktop, the DragonFly sells in a "starter package" of printer, installation and ink for around $200,000. Nano Dimension has just delivered its product to its first official customer, an Israeli defense firm. But according to the company's CEO Amit Dror, the four-year-old company has over 35 client NDAs with tier-one companies and it's in discussions or development with Fortune 100 consumer products firms, and with telecom, automotive and medical device companies in addition to the Pentagon.
Nano Dimension has one of the highest resolutions in PCB printers at 150 microns. It's aiming to get that down to 90, and, longer term, to move from prototyping to production.
IoT and 3D printing offers freedom from flat electronics
But Dror talks bigger picture, about the design freedom that multilayer 3D makes possible. "The reason things like laptops and phones are flat is because PCBs have to be flat," he said. The only way to create layers today is to accurately create each layer separately, drill them and connect them through vias (the vertical conduits of multilayer PCBs). "Look at the inner space of the curvy robots we have now; the inner space is flat. Flat is the least efficient in terms of strength and area." Weight, too, is a key factor in medical and military devices.
All of these printers, á la HP Inc., require you to use their proprietary inks; and also á la HP, make good margin on them. Nano Dimension's silver nanoparticle inks are based on a breakthrough wet-chemistry process licensed exclusively from the Hebrew University of Jerusalem. Another PCB printer maker, Voxel8, comes out of the materials science lab of Harvard Professor Jennifer Lewis. The progress of the 3D PCB printing has depended on development of conductive, silver particle inks that can sinter -- or melt into traces of suitable conductivity, adhesion and flexibility -- at lower temperatures.
Optomec, with 3D printers in the half-million-dollar range, is in 24/7 production as well as prototyping of many materials in addition to circuitry. Based in Albuquerque, New Mexico, it prints sensors and antennae directly onto curved surfaces, some of which are IoT product parts. It also prints sensors on turbine blades, for example, that are used in electrical generating systems. The sensors report metal fatigue to a central monitoring facility in time to perform preventive maintenance. Optomec's aerosol jet technology, developed by DARPA, also prints traces fine enough -- from 10 microns to 3 millimeters -- to make passive devices, like resistors and capacitors, as well as circuitry. Michael O'Reilly, director of aerosol jet product management at Optomec, said that the company is currently working under NDA with manufacturers of smart medical devices, too.
Then there's Xerox's PARC Lab, which is developing materials and 3D printing systems with different functional dispense heads for ink-jet, aerosol and extrusion. At SEMICON West 2016 in July, Bob Street, senior research fellow at PARC, gave a presentation, "Printed hybrid arrays for health monitoring," in which he discussed optical sensing to monitor body signals such as blood oxygen, electrochemical sensing to detect specific enzymes and PVDF-printed pressure/accelerometers for extreme physical conditions such as concussions.
Body and smarts
The aforementioned Voxel8, out of Somerville, Mass., makes a two-headed 3D printer that prints both thermoplastic body and embedded circuitry. Its homepage video shows its "Developer's Kit" printer printing the bottom half of the orange body of a miniature drone, in the middle of which human hands snap a PCB into place. The printer also lays down traces from PCB to the drone's rotors before finishing the top of the plastic shape, which suddenly sprouts propellers and flies away.
The desktop, multi-material Developer's Kit sells for around $10,000. Its minimum conductive trace width is 250 microns, and its silver conductive ink cures at room temperature, permitting it to be printed on thermoplastic. It's selling to universities and materials researchers, said Scott Janousek, technical support engineer at Voxel8, and it's aiming for now at prototyping and small-batch production.
Voxel8 has also partnered with Autodesk on Project Wire, a new Spark-powered tool for designing precisely what Voxel8's Developer's Kit can make, i.e., 3D electronic circuits embedded in an "arbitrary" (free-form) object. Autodesk's Spark Investment Fund is one of the investors in Voxel8's $12 million Series A funding of July 2015.
For now, the future of IoT and 3D printing is certainly promising. Look for more PCB designers to adopt 3D-printing prototyping, and then turn their tested design files over to board production houses once the bugs are shaken out. Further down the road, look for new 3D design software and production 3D printers to produce 3D circuitry that conforms to device design, and not vice versa.
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