Understanding effects of printhead geometry in aerosol jet printing

Abstract

Aerosol jet printing offers a versatile, high-resolution digital patterning capability broadly relevant to flexible and printed electronic systems. Despite its promise and numerous demonstrations, the theoretical principles driving process outputs have not been thoroughly explored. Here a custom-built, modular printing system is developed to provide a head-to-head comparison of two print nozzle geometries to better understand the technology. Print resolution data from a range of process parameters are analyzed using a support vector machine framework. The linear deposition rate is identified as a key variable, which can confound careful studies of printing performance. Taking this into account, a clear difference is observed between the printheads, corresponding to a difference in resolution of 57% ± 11% under typical conditions. Models to understand differences in aerodynamic and mass transport effects identify enhanced drying within a large diameter printhead as a likely cause of this difference. Overall, this study provides improved understanding of the aerosol jet printing process, including valuable insight to inform process optimization, robust data analysis, ink formulation, and printer geometric design.

3D Networks of Silver Nanorod–Nanoparticle Hybrids via Aerosol Jetting Printing for Flexible Electrode

“…[ 47,48 ] During the AJP process, the aerosol droplets loading with solutes generated via atomization are transferred to the nozzle and thereafter are confined in the sheath gas out of the nozzle, forming a similar microfluidic process for well‐defined shaping the aerosol droplets on the substrate. [ 49 ] Meanwhile, the microscale aerosol droplets are expected to act as an optimal microreactor for mediating the formation of nanostructures, which has been verified in different aerosol processes reported previously. [ 50–52 ] Herein, the precursor inks were formulated by simply dispersing purified AgNWs in water with a concentration of 20 mg mL −1 , while the synthesis process of AgNWs follows the previously reported polyol method with the diameter of ≈20 nm and the aspect ratio of ≈3000.…”

Systematic Design of a Graphene Ink Formulation for Aerosol Jet Printing

“…A primary metric of interest is the linear deposition rate (or speed-normalized deposition rate, Figure 3b and Figure 3c, respectively), which is dimensionally equivalent to the cross-sectional area of a single printed trace and accounts for speed-dependent effects such as liquid spreading following deposition. 51 With the above-mentioned atomizer settings, it is possible to obtain patterns with comparable cross-sectional areas and, consequently, deposition rates, which allow for a meaningful comparison of the properties of sintered prints. In Figure 3a, optical profilometry data of narrow bar prints (10 passes offset) with a focusing ratio of 5 exhibit distinct morphology caused by the different ink formulations.…”

Recent Advances in Multi-Material 3D Printing of Functional Ceramic Devices

“…Akhatov et al [ 110 ] conducted the first systematic theoretical and experimental study about the effect of the Saffman force on aerosol flows through a micro-capillary, revealing complicated interactions between droplets and the carrier gas, which allowed for the optimization of focused aerosol beams. Later, many researchers explored the underlying causal aerodynamic interactions that led to trends in line morphology using computational fluid dynamic models and achieved a better understanding of aerosol droplet generation, transportation, and impaction [ 104 , 111 , 112 , 113 , 114 , 115 , 116 ]. Additionally, data-driven process modeling can eliminate the drifting and stochastic nature of the print system and efficiently determine the optimal operating process window, which is attractive for controlling the line morphology [ 117 , 118 , 119 ].…”