One of the main challenges in 3D printing electronic circuits is that the most effective material jetting processes for integrated multi-material electronic AM involve using photopolymers and silver nanoparticle (AgNP) inks, which require different types of 3D printing processes: photopolymers are cured by light while silver nanoparticles need to be sintered (that is they need heat). A recently published study by a team of researchers at the University of Nottingham’s Center for Additive Manufacturing describes a new method for sintering silver nanoparticles using the same UV-source which is used to cure the photopolymer.
The production of electronic circuits and devices is limited by current manufacturing methods that limit both the form and potentially the performance of these systems. Additive manufacturing (AM) is a technology that has been shown to provide cross-sectoral manufacturing industries with significant geometrical freedom.
A research domain known as multifunctional AM (MFAM) in its infancy looks to couple the positive attributes of AM with application in the electronics sector can have a significant impact on the development of new products; however, there are significant hurdles to overcome. This paper reports on the single step MFAM of 3D electronic circuitry within a polymeric structure using a combination of conductive and nonconductive materials within a single material jetting-based AM system.
The basis of this breakthrough is a study of the optical absorption regions of a silver nanoparticle conductive ink which leads to a novel method to rapidly process and sinter AgNP inks in ambient conditions using simple UV radiation contemporaneously with UV-curing of deposited polymeric structures.
Printing silver-nanoparticle inks alongside polymeric inks is challenging due to the high temperatures required for sintering, which can damage the polymer. Here, a method to sinter silver-nanoparticle inks using ultra-violet light which is absorbed by the nanoparticles generating localized heat is introduced. A polymeric ink is printed and solidified using the same UV source producing multi-material 3D structures in one process.