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|Author(s):||R M. Verkouteren; Jennifer R. Verkouteren;|
|Title:||Inkjet Metrology II: Resolved Effects of Ejection Frequency, Fluidic Pressure and Droplet Number on Reproducible Drop-on-Demand Dispensing|
|Published:||June 13, 2011|
|Abstract:||We report highly reproducible gravimetric and optical measurements of microdroplets enabled by fluidic pressure feedback control and state-of-the-art measurement systems that lend new insights into the process of drop-on-demand (DOD) printing. Baseline fluidic pressure within the DOD dispenser was controlled to within 0.02 hPa, enabling long-term stability in dispensed droplet mass with observed variations between 0.6 % and 1.6 % (RSD) for isobutanol. With mass, the high precision of velocity measurement enabled consistent determination of droplet kinetic energy, which governed baseline behavior. Mass and velocity were influenced in a non-linear manner by the frequency of droplet ejection, the fluidic pressure applied, and the number of droplets dispensed. Non-linear mass effects were attributable to acoustic resonances, energy partitioning, and pressure wavelets created during ,first-dropŠ formation, although mechanistic clarity is far from complete.|
|Pages:||pp. 9644 - 9653|
|Keywords:||droplet, drop-on-demand, first-drop, fluidic pressure, gravitmetry, inkjet, microbalance, piez|
|PDF version:||Click here to retrieve PDF version of paper (3MB)|