3D Printing and Additive Manufacturing of Electronics

The following sections are included:

• Dedication
• Preface
• About the Authors
• Acknowledgements
• Contents
• List of Abbreviations

Electronics have become one of the essential necessities of life in modern society. It is hard to imagine what the world would be like without electronics. Everything from entertainment to healthcare uses electronics in some way or another. Many electronic devices, such as smartphones, computers and gaming consoles, have also revolutionised the way we communicate, live, work and play — and with increasing convenience — over the past few decades.

As the name suggests, contact printing techniques require the contact of a printing plate or an image carrier with the substrates for ink transfer. The images or patterns can be printed on the substrates, either directly or indirectly, from a master plate. The master plate carries the image information in the form of engravings, but it cannot be amended freely once fabricated. Hence, the contact printing techniques are only cost-effective for high volume printing…

In recent years, 3D electronics printing has been emerging as a technology capable of harnessing the potentials of additive manufacturing in fabricating electronics and structural electronics. Electronics fabricated by additive manufacturing techniques, i.e. those involve materials deposition processes, are normally termed as “3D printed electronics” or “additive manufactured electronics (AMEs)”…

3D printing approach can be used to fabricate electronic components by depositing a wide variety of functional materials onto substrates. These materials include metallic nanoparticle inks, metal-organic decomposition (MOD) inks, conductive polymers, carbon nanotubes (CNTs), graphene, semiconductor inks and dielectric inks. This chapter provides an overview of the types of inks used in 3D printing of electronics, their physical properties, as well as their advantages and disadvantages.

Conventionally, electronics are fabricated on rigid, brittle and planar substrates (for instance, FR-4, glass and silicon wafers). However, these rigid substrates lack conformability, bendability and stretchability that may be required for more innovative applications such as conformal electronics, flexible electronics, and stretchable electronics [1—4]. Therefore, substrates play a vital role in 3D printed electronics since they are the base materials for the deposition of functional inks and materials through various 3D electronics printing techniques. Most 3D electronics printing techniques have the capability to print directly onto planar and conformal surfaces and thus, giving the users a wide range of different type of substrates to choose from. The choice of substrates for 3D printed electronics is highly dependent on the ink properties, the required sintering techniques, and the intended application. Some of the critical properties of the substrates that influence the printing and device fabrication processes include surface wettability, surface smoothness, cost, optical transparency, heat resistance, thermal expansion, film thickness, mechanical properties such as, hardness, conformability, bendability and stretchability.

Metallic nanoparticle inks are commercially available in the market and widely used for printed electronics applications. They are typically favoured over metal-organic decomposition (MOD) inks as they have better electrical conductance and omit the need for additional chemical reduction processes. However, undesirable coffee ring effects are prominent and inevitable on deposited metallic nanoparticle inks, in which metallic nanoparticles tend to concentrate on the perimeters…

Additive manufacturing (AM) technology has revolutionized the conventional way of fabricating and designing electronics, by providing many opportunities in fabricating 3D printed electronics with interesting and complex designs. With the emergence of new printing materials and processes, the technology for fabricating 3D printed electronics has improved immensely over the years. However, the complexity of the interdisciplinary interactions taking place during 3D electronics printing processes also has increased considerably. Therefore, there is a need for computational modelling and simulations to help investigate the underlying mechanisms and optimise the printing processes more effectively and efficiently. The direction for 3D printed electronics has also gradually shifted to the fabrication of components with multi-material, multi-functionality, and multi-scale, to meet the needs and demands of more advanced applications…

In recent years, great progress has been made in 3D printing of electronics. Significant efforts have been put into developing advanced printing systems and functional inks, refining printing processes, optimising sintering processes, using computer simulations for optimising designs and even integrating machine learning algorithms for printing. 3D printed electronics has been considered to be one of the next upcoming new frontiers of additive manufacturing and it is set to revolutionise the electronics industry in the near future. With the advanced software, machines and functional inks, our imagination is the only limit to what we can fabricate for 3D printed electronics applications.

In literature, there are myriads of 3D printing electronics applications and this chapter is unable to cover them exhaustively. Hence, this chapter only highlights some of the electrical components and devices that are commonly used for 3D printed electronics, including passive components, active components and sensors. Their basic architecture designs, operatingu mechanisms and functionalities are discussed greater in details and showcase the potentials of using additive manufacturing technologies for motivating further advances in 3D printed electronics. This chapter lastly also discusses the future outlook of 3D printed electronics.

The following sections are included:

• Appendix
• Index