3D printing PCBS: a 30-year-old idea is coming in vogue, with stunning implications for design engineering.
Ten Have is CEO and cofounder of Ponoko, the company behind Personal Factory, a web-based platform for the creation of custom goods. Ponoko users can make their own products using a variety of digital manufacturing methods, including laser-cutting, CNC routing, and 3D printing. More than 100,000 consumer-designed products have been made, and demand for 3D printing is on the rise.
3D printing is an additive manufacturing technique that translates digital models into physical objects by building up layers of material. A number of competing 3D printing technologies variously use chemical-, heat- or light-based methods to fuse material together layer-by-layer. Resolution depends on the printer type, but some of the more advanced machines can achieve a resolution in the micron range. For instance, the Objet Connex desktop printer has a minimum layer thickness or 16 [micro]m.
While many of these technologies have been in use since the 1980s, 3D printing has become much more accessible in recent vears as a result of increased functionality and decreased cost. Companies like Ponoko, Sculpteo and Shapeways have emerged to provide online 3D printing services. Open source hardware projects like the MakerBot, RepRap, and Fab@Home have brought 3D printing technology within reach of the home hobbyist, with kit sets available for under $1,000. These machines in particular have been enthusiastically embraced by the DIY electronics communities.
There are two distinct advantages of using 3D printing over traditional manufacturing that could lead to some dramatic changes in many areas of industry: The first is it undermines economies of scale; it is now possible to make one-off objects that would otherwise have required mass-production. The implications both for prototyping and customization are profound. The second advantage is it makes it possible to produce objects that could not be made in any other way, as a result of complexity or internal features. Complex assemblies of moving parts can be designed to come out of the machine preassembled.
3D printing circuit boards. PCB production is an application for 3D printing being pursued both by industry and hobbyists. Developments are primarily focused on material research at present. 3D printing has been demonstrated with many different kinds of metals, plastics, ceramics, polymers and organic materials. With the right combination of materials, modern multi-material printers would have no trouble printing PCBs. Being able to produce high-quality, multilayered one-off boards would be a huge advantage for design engineers and home hobbyists alike, greatly simplifying the prototyping cycle and removing the time and material expense of masking and etching.
Hobbyist-led advancements. In the hobbyist realm, early signs of development in this area came in 2009 when Bath University mechanical engineering student Rhys Jones revived the old idea of making PCBs by depositing metal into preformed channels. He modified his RepRap 3D printer to extrude molten solder into a pre-printed ABS plastic substrate. While the melting point of solder is higher than that of ABS, the specific heat of the metal is so low that the plastic doesn't melt. After manual assembly, the completed circuit was then installed on the actual machine that printed it. This was an early milestone for the RepRap project, whose stated aim is to create self-replicating machines.
While this process is still in its infancy, it could soon prove to be popular with home 3D printing enthusiasts that want basic custom circuit boards, without dealing with the hit-or-miss home PCB etching process. Another bonus to 3D printed circuit boards is the integration of mechanical features. For example, it would be elementary to include mounting clips in the design.
Another open source project, Fab@Home, has demonstrated the use of conductive and non-conductive silicone to print flexible objects with internally embedded circuitry laid out in three dimensions.
The rise of DIY electronics. Hobbyist 3D printing and DIY electronics are two major forces democratizing technology, and their development is entwined. In 2005, the launch of yet another open source project, the Arduino, marked a turning point in the world of hobby electronics. Arduino rapidly gained a reputation as the first truly user-friendly micro-controller development platform.
This platform opened up the world of embedded computing to a much larger audience, and it remains popular among artists, educators, and hobbyists, with an ever-increasing number of extension modules (e.g., sensors, driver boards, communication interfaces, etc.) available. These modules, known as "shields," take the form of traditional PCBs that can be plugged into the Arduino board with stacking headers.
3D printing creates the possibility for these modules to take any shape, a feature that could further functionality and user-friendliness of these shields. For instance, one can imagine a modular robotics system with an Arduino processor embedded into a printed "torso," a camera or rangefinder embedded into a printed "head," and interchangeable "limbs" containing other sensors and actuators, with all associated electronics integrated seamlessly into each piece.
With the increasing popularity of DIY electronics and 3D printing, it is fair to assume that progress will continue to empower the home hobbyist with ever more capable and user-friendly fabrication techniques. One immediate area of development to look out for is a standardized file-format--a common protocol for defining designs. This will be the precursor to any serious activity in the open source community.
Industry-led advancements. Looking to the industrial realm, Dutch research institute TNO (tno.nl) has pioneered a number of different circuit printing technologies. It recently printed a simple circuit in copper, along with flexible integrated housing, all in one step. This hints at another exciting and disruptive possibility of 3D printing; it allows the designer to do away with the circuit board altogether, integrating the electronics with other functional parts of the product.
As these technologies become established, 3D printed circuits could lead to tearing down several design constraints. For starters, there's no reason a 3D-printed board would have to be a typical rectilinear planar surface (FIGURE 1). Disrupting the 2D PCB design paradigm could have some radical implications for design engineering. Traditional flat PCBs force design constraints on the layout of components and inefficiencies on space and material usage, constraints that will disappear when the PCB can take any conceivable shape.
[FIGURE 1 OMITTED]
Yet another benefit of using a 3D printer to build circuit boards is that many types of printers share most of their mechanical characteristics with a pick-and-place component assembly machine, meaning an all-in-one PCB printing and assembly unit could be just around the corner.
Beyond simply changing the way we make circuit boards, developments in printing technologies are set to potentially revolutionize the production of all kinds of electronic components. 3D printer manufacturing firm Objet recently mused on its company blog about the likelihood of printing both circuit boards and integrated semiconductor components at a point "not too far in the future."
Academia-led advancements. Some of the bleeding-edge technologies at the R&D stage today indicate some very exciting developments for printed electronics in the longer term.
Printed solar panels are flexible and significantly lighter and cheaper than their traditional clunky glass-mounted counterparts. Developments in this field over the last few years have substantially reduced the cost, with the Holy Grail being small, disposable power for applications such as smart packaging. Researchers at MIT(1) recently demonstrated a highly flexible and robust solar panel printed on paper "almost as cheaply and easily as printing a photo on your inkjet."
This comes in the wake of Stanford University's research in the field of nano-material technology, proving it is possible to store energy in super-capacitors made by printing carbon nanotubes onto treated paper(2).
The flexibility of printed electronics has the potential to be hugely influential in other applications, especially mobile devices where a printed flexible OLED display could be unfolded to a size larger than a handset. Flexible interactive screens are in the prototype stage, and printed e-ink displays already have been demonstrated playing color video on a paper-thin plastic substrate.
Other recent advancements include printed sensors, transistors, and low-density data storage, meaning entire consumer devices could one day be conceivably printed in one continuous process on a single machine. Aggressive research efforts in industry, academia, and the growing community of sophisticated hobbyists make the field of 3D printed electronics a fascinating and important one to keep an eye on.
(1.) Miles C. Barr, et al, "Direct Monolithic Integration of Organic Photovoltaic Circuits on Unmodified Paper," Advanced Materials, vol. 23, no. 31, Aug. 16, 2011.
(2.) Katherine Bourzac, "Print on Demand Power, MITTechnology Review, April 27, 2009.
RICHARD D. BARTLETT is an engineer, artist, writer and practicing futurist based in Aotearoa, New Zealand.
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|Title Annotation:||BOARD FABRICATION|
|Publication:||Printed Circuit Design & Fab|
|Date:||Apr 1, 2012|
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