Today, 3-D printing is the most popular technology among all manufacturing and prototyping methods. However, 3-D printing is not new. In the 1980s, a company filed a patent for 3-D constructing models using stereolithography. Such patents have been instrumental in holding back the development, manufacture, and distribution of 3-D printing technology, until now.
3-D printing typically works by slicing a 3-D design into several small horizontal 2-D sections and then splicing them together by printing each 2-D slice atop the other. 3-D printers commonly use a thermoplastic wire wound on a reel. The printer extrudes this wire through a hot nozzle. There are 3-D printers that build models from paper. They cut out each layer from the paper, and glue one layer to the next. Other, more advanced systems sinter metallic dust using lasers.
It is possible to use 3-D printing technology for manufacturing electronic components. This uses a printer and an additive process. However, not all see the 20-D printed electronics as being actually 3-D printed. For instance, although they consider transistors as 2-D, in actual practice, they are 3-D, requiring both additive and subtractive processes to build up their insulating layers, source and gate terminals.
For now, there is little practical application for most 3-D printed electronics, and their use in the real world is rare. This is so because manufacturing electronics in the traditional manner is much easier, cheaper, and more reliable. Still, there is a significant amount of research for trying and creating practical devices with 3-D printing technology. So far, there has been significant success in printing transistors, capacitors, diodes, and resistors using 3-D processes.
Although electronic components may use several materials, 3-D printed devices generally use graphene or other organic polymers. Researchers use graphene, as it gives them the ability to create narrow channels and gates while allowing doping. It is easy to dispense organic polymers in solution form, which is ideal for using them in inkjet printers.
However, with printed electronic capabilities still far removed from standard electronic systems, it is rare to find commercial applications for printed electronics. However, there is plenty of research going into printing them.
Being still in their infancy, printed electronics are presently found only in research labs, or in prototypes. There are two technologies popular, tending towards practical—Pragmatic and Duke University.
A UK-based company, Pragmatic, produces printed electronic components for one-time applications. These are disposable electronic items like RFID tags. The most significant feature of Pragmatic devices is they use a flexible substrate. They cover all essential components like resistors, capacitors, and transistors. Although Pragmatic has not fully demonstrated a functional device, they have produced ARM core processes, claiming each device consumes 21 mW and energy efficiency of 1%.
Presenting the best examples of practical printed electronics, Duke University claims its products exceed the typical life cycle. They use a new method of additive processes for creating printed electronic components like resistors, capacitors, and transistors. Their components are mostly based on carbon, while the construction uses aerosol spraying similar to inkjet technology. They build the insulating layers from cellulose.
