Almost any electronic technology has one truism attached to it: You can't develop it if you can't test it. This is particularly the case with wireless and other communications products. Unfortunately, getting from design to prototype to test can take a month or more. Product developers must first navigate an evolving set of design requirements characterized by smaller form factors, shorter development cycles and flexible packaging. Tweaking the design often means generating a new prototype, and adding another month to the schedule.
"Product designers are eager to shorten the time it takes to go from concept-to-prototype-to-test in large part because their customers are asking for it," said Brian Smith, principal member of the technical staff at The Charles Stark Draper Laboratory, Inc (Draper) "If your market is looking for products in more variety, with varying capabilities and in different form factors, your product designers are on the hook to rapidly churn out prototypes. That's not easy with the current approach to electronics manufacturing."
Draper turned to 3D printing to address this challenge and equipped a 3D printer with a conductive metal-based multi-material ink that could serve as a form of sprayable electronics for printed circuit boards and other electronics. Such multi-material 3D printing is a type of additive manufacturing that is starting to replace traditional subtractive manufacturing that has long been used to make printed circuit boards, among other technologies.
"Given that electronics are fundamentally multi-material systems, the challenge lies not just in material formulation but also material-material interaction including chemical compatibility, adhesion, temperature processing and induced stresses," said Peter Lewis, a member of Draper's technical staff and co-author of a study on 3D printing using aerosol jet printing.
With AJP, product developers can print integrated electronics onto plastic, ceramic and metallic structures at extremely fine resolutions. "This enables the high-volume production of 3D-printed components, such as an antenna or sensor, that is tightly integrated with an underlying industrial component," Lewis said.
Using AJP and a novel metal-based ink, Lewis, Smith and Robert White, a co-author of the study and Associate Professor, Department of Mechanical Engineering at Tufts University, fabricated a multilayer system-on-a-chip microprocessor and put it through a series of environmental and rapid aging tests, exposing it to thermal shock, temperature swings from -55 C to 125 C and moisture and insulation resistance tests. Their tests showed that conductive inks can remain functional through intense aging environments, which can lead to a longer life for a device, and reduce the profile of wire bonds for microprocessor, which can translate to a smaller device.
"Without a doubt, AJP technology results in electronic systems fabrication with much greater versatility," said White. "Among all of our findings, we were most surprised to find that the 3D multi-material printer reduced the concept-to-prototype fabrication time for a microprocessor from many weeks and even months to just a few days. We see many uses for aerosol jet printing (AJP) technology, where the entire system can be deposited on a 3-D, potentially flexible, substrate, and not confined to two-dimensional planes. In particular, Internet of Things (IoT) applications are a good fit because they require small, conformal modules integrating standard commercial off the shelf (COTS) components with a fast time-to-market and simple circuit customization/revision."
This work is part of Draper's ongoing commitment and internal investment in additive manufacturing applied to electronics. Draper's additive manufacturing capabilities enable designs that otherwise cannot be built. For instance, Draper has developed an antenna using aerosol jet metal 3D printing and a patent-pending hybrid 3D-microelectronics process, a process which combines two of Draper's advanced technologies: 3D printing and microelectronics. The function-based approach to development reduces manufacturing cost, size, weight, and power requirements, and enables diversified design shape and structure in emerging technology spaces.
Source and top image: The Charles Stark Draper Laboratory, Inc
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