Development of an Inkjet Setup for Printing and Monitoring Microdroplets

Abstract

Inkjet printing is a digitally controlled additive technology that allows the precise deposition of droplets. Because it is additive, it enables geometries usually unattainable by other technologies. Because it is digitally controlled, its output is easily modulated, even during operation. Combined with the development of functional materials and their micrometer precision, it can be applicable in a wide range of fields beyond the traditional graphic industry, such as medical diagnosis, electronics manufacturing, and the fabrication of microlenses. In this work, a solution based on open-source hardware and software was implemented instead of choosing a commercial alternative, making the most of inkjet flexibility in terms of inks, substrates, and actuation signal. First, a piezoelectric printhead from MicroFab, driven by an ArduinoDue, was mounted in a 3D printer adapted to ensure precise movement in three dimensions. Then, a monitoring system using a USB digital microscope and a computational algorithm was integrated. Both systems combined allow the printing and measurement of microdroplets by digital regulation of a unipolar signal. Finally, based on a theoretical model and a set of experimentally collected samples, the curve that relates the unipolar signal amplitude to the size of the microdroplets was estimated with an acceptable range of prediction uncertainty.

Inkjet Printing Optimization: Toward Realization of High‐Resolution Printed Electronics

“…Basically, the driving waveform comprised three primary stages: I) ink drawing/pulling, II) stabilization, and III) ink jetting/pushing, as depicted in Figure 9a. [112,113] At the beginning of the printing process, PZT bends outward, allowing the chamber to expand and ink to be drawn from the reservoir and nozzles into the chamber. Subsequently, the chamber stabilizes to facilitate the propagation of the pressure waves through the dispenser (Stage II).…”

“…Reproduced under the terms of the CC‐BY license. [ 112 ] Copyright 2022, Multidisciplinary Digital Publishing Institute; b) Unipolar and bipolar waveforms with pull‐push‐pull mode. Reproduced under the terms of the CC‐BY license.…”

“…Figure 9. a) Standard waveform with pull-push mode (left) and schematic representation of deformation on piezoelectric crystal in printhead (right).Reproduced under the terms of the CC-BY license [112]. Copyright 2022, Multidisciplinary Digital Publishing Institute; b) Unipolar and bipolar waveforms with pull-push-pull mode.…”

Performance Study of Piezoelectric Injection System Based on Finite Element Simulation

“…The image processing technique can calculate the number of pixels, combine it with the time recorded by the camera, and then obtain the jet speed, according to the displacement time equation. The droplet diameter can also be obtained by acquiring the number of pixels in the area [26,27]. Figure 12 shows the comparison of the simulation and experimental results.…”

Editorial for the Special Issue on Recent Advances in Inkjet Technology

“…The findings of this study demonstrated how to obtain a silver film with the necessary qualities. Cavaleiro de Ferreira et al [ 18 ] developed a very simple and low-cost drop monitoring system. The team attempted to utilize readily available components, resulting in a system that can be easily replicated by anyone.…”