Integration of additive manufacturing and inkjet printed electronics: a potential route to parts with embedded multifunctionality

Abstract

-Additive manufacturing, an umbrella term for a number of different manufacturing techniques, has attracted increasing interest recently for a number of reasons, such as the facile customisation of parts, reduced time to manufacture from initial design, and possibilities in distributed manufacturing and structural electronics. Inkjet printing is an additive manufacturing technique that is readily integrated with other manufacturing processes, eminently scalable and used extensively in printed electronics. It therefore presents itself as a good candidate for integration with other additive manufacturing techniques to enable the creation of parts with embedded electronics in a timely and cost effective manner. This review introduces some of the fundamental principles of inkjet printing; such as droplet generation, deposition, phase change and post-deposition processing. Particular focus is given to materials most relevant to incorporating structural electronics and how post-processing of these materials has been able to maintain compatibility with temperature sensitive substrates. Specific obstacles likely to be encountered in such an integration and potential strategies to address them will also be discussed.

Laser‐Induced Forward Transfer: A Digital Approach for Printing Devices on Regular Paper

“…It can be observed how lines become thicker as the number of prints increases, and how their cross‐section gets closer to the ideal rectangular shape, [ 1 ] which contrasts with the irregular cross‐sections (due to the coffee‐ring effect) typical of the lines printed with IJP. [ 8,20,48,59 ] The high viscosity and large particle size of the Ag‐SP ink prevent significant redistribution of the ink once it is deposited, and this mitigates the Marangoni flow that is responsible for the coffee‐ring effect, so detrimental for the electrical conductance of the lines.…”

“…[ 19 ] This results in inks with relatively low solid content, which in the case of conductive inks leads to interconnects with poor sheet resistance, and therefore to devices with a performance far from those fabricated using the techniques described above. [ 20 ] Conductive inks are the most abundant material in printed circuitry since they serve as interconnects between the different components of any device. Therefore, printing them is fundamental for demonstrating the potential of any PE technique.…”

“…[ 36–38 ] Thus, SP inks—with high viscosity (>10 Pa s) and usually loaded with large particles (a few micrometers)—can be printed using LIFT, [ 39–43 ] though not through IJP. [ 19,20 ] These rheological properties are compatible with high solid contents, and in the case of conductive inks, they can result in the fabrication of interconnects with sheet resistances as low as 50 mΩ □ −1 , [ 5,44–46 ] much lower than those resulting from IJP (around 1 Ω □ −1 ). [ 5,6,46–48 ] All of this makes LIFT an interesting candidate as the digital alternative aimed at in the preceding paragraph.…”

Hybrid additive manufacturing of the modified electrolyte‐electrode surface of planar solid oxide fuel cells

“…Table 2 depicts the density and thickness of ink A and B recorded from the SEM image from the cross section. Coffee staining effect is an inevitable phenomenon leads to non‐uniform distribution of thickness on the printed area 25 . Ink B leads to a thicker layer because of more solid loading in the initial slurry.…”

Pinhole‐Free Inkjet Printing Strategies for Organic Electronics

“…Inkjet printing has become an important technology for flexible and organic electronics and is considered to extend its market share to more than 18% compared to other printing technologies in the field of printed electronics until the end of the decade…”