For those in urgent need of printed circuit boards for prototypes and other purposes, PCB Trace Technologies Inc suggests 3-D printed boards. It is much faster to make 3-D printed circuit boards compared to methods using traditional technologies. 3-D printing is more versatile, and produces significant cost savings while being able to produce more complex circuits.
One of the major appeals of 3-D printed circuits is that OEMs have control over their circuit board supply, allowing them to eliminate possible disruptions from plant shutdowns, geopolitical manoeuvring, and shipping slowdowns. All these can stretch circuit board supply chains to the breaking point, leaving OEMs scrambling for alternatives.
Although at present, this technology is still a niche, and requires more R&D for scaling it to the levels not only of mass-production, but also for rapid prototyping, small-scale production. Aerospace and military applications are especially suited to 3-D printed circuits, and electronic manufacturers can use them to validate iterations for gaining practical intuition they would not get by outsourcing their fabrication.
So far, there have been rapid advancements in 3-D printed PCB technology. Already, this technology has enabled manufacturers to accelerate their new products for market. For instance, one 3-D printer maker is providing semiconductor solutions for increasing 5G signals.
Manufacturers have been quick to embrace 3-D printing technology for their PCBs. For this, they require the use of suitable 3-D printers, proper software for designing 3-D PCBs, and other additive manufacturing methods. 3-D printing is also affecting the circuit board industry, with additively manufactured fixtures and tools necessary for production of PCBs.
With specialized 3-D printers, manufacturers can make boards much faster than by using conventional methods. For instance, it is possible to use the common desktop 3-D printer and conductive filament while making PCBs for some applications.
While the turnaround time for creating a traditional circuit can be as high as few days or weeks depending on the complexity, using 3-D printers, it is possible to cut down the turnaround time to 30 hours or less. Another significant factor for 3-D printing is design freedom. Using 3-D printers, it is possible to create circuits in more complex shapes than it is possible with traditional methods. All types of circuit boards are possible to make, including rigid, rigid-flex, flexible boards, boards with honeycomb structures, and even three-dimensional boards.
3-D Printed Circuit Board Technology
Primarily, there are two methods that 3-D printed circuit board manufacturers use:
- Circuits using conducting materials
- Boards using hollow channels (later filled with conductive materials)
Traditional methods of printed circuit board manufacturing primarily use the subtractive method. This mainly uses chemical means for etching copper circuits onto a board, or mechanically removes unwanted copper by milling, leaving conductive traces.
Circuits Using Conductive Materials
Using conductive materials is presently the most common and popular method of 3-D printing circuit boards. In this method, 3-D printers place a conductive ink, to form the circuitry on a base substrate. The conductive material begins as ink or filament that has conductive particles infused in them. These particles can be graphite, copper, or silver. Instead of using printers, some manufacturers also spray them as aerosol-laden streams.
Commercial 3-D printers most commonly use conductive inks. These printers are very similar to the 2-D inkjet printers that deposit droplets of ink on the paper. The 3-D printers deposit two types of droplets, one of conductive ink, and the other of insulating ink to build the circuitry.
Here again, there are two types of printers. Some printers can only print on a prefabricated substrate board. Other printers can print the substrate board as well. In the second case, the 3-D printer can produce very complex, multi-layered, double-sided circuit boards that contain embedded components, such as LEDs, resistors, and coils.
An example of such a board is a 10-layer 3-D printed circuit board for the defense industry. This high-performance electronic structure has components soldered on both its outer surfaces. Dielectric polymer ink forms the substrate, while the traces use conductive ink. The printed circuit board uses a 3-D printer that can print with both conductive and insulating ink simultaneously.
Another option available is by using conductive filaments. It is possible to use any FDM or Fused Deposition Modeling printer for the purpose. FDM printers use the FFF or Fused Filament Fabrication technique, an additive manufacturing process, a form of material extrusion. The printer builds the filament layer by layer by selectively depositing molten conductive material in a predetermined path.
Although cost-effective, 3-D printed boards using conductive filaments are bulkier and less effective compared to ink-based PCBs. 3-D printed circuit boards may not be suitable for commercial applications, but they can be ideal for prototypes.
Boards Using Hollow Channels
This method produces a board that has hollow channels in place of the usual circuitry. Essentially, the printer produces a case for holding the conductive material that it will later deposit. For initial printing, the printer must use a non-conductive filament for producing the board. Later, it will use a conductive material to fill the circuit channels.
With a sufficiently accurate 3-D printer, it is possible to create virtually any type of PCB. Being a very economical solution, the hollow channel method can offer tracks with higher conductivity as compared to other printed circuits, including those made with conductive filaments.
Advantages of 3-D Printed Circuit Boards
Cost Effective
While some 3-D printers are expensive, they quickly provide a return on the investment. This is mainly because 3-D printed boards consume fewer materials. Moreover, as the boards can be manufactured in-house, they eliminate shipping and outsourcing costs, making them cheaper.
Low Turnaround Time
Turnaround time, or production time, for PCBs using 3-D printing techniques, is in hours and not days. This can help to speed up the entire production pipeline, starting from circuit design, prototyping, iterations, and finally, to production and market rollout.
High Design Freedom
With 3-D printing, it is possible to make PCBs of practically any shape and size. It is possible to make them of flexible materials as well. Engineers with higher design freedom can concentrate on other design aspects like using lighter material, and making the design more safe, efficient, and smaller.
Less Wastage
Traditional methods of fabricating printed circuit boards produces a huge amount of waste materials. Using 3-D printing allows making the circuit very compact using complex shapes. This not only saves material, but also saves money. Most OEMs use the low-waste angle for advertising their products.
On-Demand Production
With 3-D printing, it is not necessary to keep large inventories for producing circuit boards. Moreover, OEMs do not have to commit to larger orders from PCB manufacturers. In addition, OEMs can eliminate the chances of supply chain disruption.
Higher Resolution and Repeatability
It is possible to achieve much higher resolution using 3-D printing technology than using traditional methods for producing printed circuit boards. It is also possible to place components using some printers. This simplifies the production process for making the boards. It is possible to design and fabricate more complex boards when using additive manufacturing techniques using 3-D printing for high layer count boards.
Disadvantages of 3-D Printed Circuit Boards
Material Limitations
As 3-D printing is rather a new technology, there are material limitations. That means, it is not possible to have the extensive range of materials for 3-D printing that conventional PCB manufacturing techniques offer. Most printers can use only one or two materials, and this increases the costs, while reducing design choices. Printers that use more materials are more expensive as well.
Conductivity Issues
Although there have been constant advances in 3-D printing technology, conductive printing materials still have conductivity issues. Compared to copper traces in traditional PCBs, conductive printing inks are less conductive.
Board Size Limitations
3-D printers can produce boards as large as their print chambers allow. This may not be an issue for small board sizes, as the chambers in most 3-D printers are rather small. However, that also means such printers are rather unsuitable for producing larger circuit boards.
Lack of Options
At present, very few companies are making commercial 3-D printers for circuit boards. However, as the technology matures, the situation is likely to improve. But for the time being, OEMs are limited to the choice of options.
Conclusion
According to PCB Trace Technologies Inc, it is no longer necessary to restrict the design of boards to flat PCBs. Using 3-D printing technology, it is possible to make circuits of practically any shape. For instance, in the recent demonstrations at ICP APEX, there was a 3-D printed circuit cylinder. Manufacturers have the advantage of being able to fit 3-D printed boards into smaller spaces while producing them at lower prices. While the technology is still proceeding toward commercialization, this is the trend of the evolution in the industry.
