One Dimensional Simulation of Droplet Ejection of Drop-on-Demand Inkjet

2017 ◽  
Author(s):  
Huicong Jiang ◽  
Hua Tan
Keyword(s):  
Method Of Lines ◽  
Driving Pressure ◽  
Navier Stokes ◽  
Drop Breakup ◽  
Nozzle Orifice ◽  
On Demand ◽  
2D Simulation ◽  
Drop On Demand ◽  
Droplet Ejection ◽  
Fluid Properties

In this study, we present a 1D method to predict the droplet ejection of a drop-on-demand (DoD) inkjet which includes the drop breakup, coalescence, and the meniscus movement at nozzle orifice. A simplified 1D slender-jet analysis based on the lubrication approximation is used to study the drop breakup. In this model, the free-surface (liquid-air interface) is represented by a shape function so that the full Navier-Stokes (NS) equations can be linearized into a set of simple partial differential equations (PDEs) which are solved by method of lines (MOL). The shape-preserving piecewise cubic interpolation and third-order polynomial curve are employed to merge approaching droplets smoothly. The printhead is simplified into a circular tube, and a 2D axisymmetric unsteady Poiseuille flow model is adopted to acquire the relationship between the time-dependent driving pressure and velocity profile of the meniscus. Drop breakup and meniscus movement are coupled together by a threshold of meniscus extension to complete a full simulation of droplet ejection. These algorithms and simulations are carried out using MATLAB code. The result is compared with a high fidelity 2D simulation which was previously developed [10], and good agreement is found. This demonstrates that the proposed method enables rapid parametric analysis of DoD inkjet droplet ejection as a function of nozzle dimensions, driving pressure and fluid properties.

Laser Induced Nano-Droplet Ejection for the Construction of Nano-Inkjets

2012 ◽  
Author(s):  
Yu Yang ◽  
Vijay M. Sundaram ◽  
Alok Soni ◽  
Sy-Bor Wen
Keyword(s):  
Surface Tension ◽  
Pulse Energy ◽  
Nanosecond Laser ◽  
Continuous Laser ◽  
Fluidic Channel ◽  
Robust Approach ◽  
Power Intensity ◽  
On Demand ◽  
Drop On Demand ◽  
Droplet Ejection

To achieve precise nano-droplet ejection, the existing microscale inkjet module could be scaled down to nanoscale, including both the fluidic channel and the pressure driver. While 2D/3D nanoscale fluidic channels are currently available, a nanoscale pressure driver providing high enough power intensity to overcome surface tension for nano-droplet ejection is still lacking. In this study, laser induced nanoscale confined heating with nano-nozzles are constructed and demonstrated as a simple and robust approach to achieve the required pressure driver. For the heating with continuous laser, micro spray composed with nano-droplets can be induced from the nano-nozzles. For the heating with nanosecond laser of adequate pulse energy, drop-on-demand ejection of droplets with similar diameter as the apertures of the nano-nozzle can be achieved.

Effects of nozzle and fluid properties on the drop formation dynamics in a drop-on-demand inkjet printing

2019 ◽  
Vol 40 (9) ◽  
pp. 1239-1254 ◽  
Author(s):  
A. B. Aqeel ◽  
M. Mohasan ◽  
Pengyu Lv ◽  
Yantao Yang ◽  
Huiling Duan
Keyword(s):  
Inkjet Printing ◽  
Drop Formation ◽  
On Demand ◽  
Drop On Demand ◽  
Formation Dynamics ◽  
Fluid Properties

Relevant Influencing Factors on Droplet Characteristics for a Piezoelectrically Driven Drop-on-Demand Printhead

2014 ◽  
Author(s):  
Markus Kagerer ◽  
Arne Meeuw ◽  
Jan Berger ◽  
Dominik Rumschoettel ◽  
Tim C. Lueth ◽  
...  
Keyword(s):  
Surface Tension ◽  
Formation Process ◽  
Droplet Formation ◽  
Electrical Excitation ◽  
Fluid Mixture ◽  
Nozzle Length ◽  
On Demand ◽  
Drop On Demand ◽  
Fluid Properties

Dispensing minute amounts of fluid is used in many industries, such as in life science, bioengineering, 3D printing, or in electronics manufacturing. Each application for drop-on-demand (DoD) printheads requires different drop volumes and drop velocities. Furthermore, it is necessary to eject droplets made of fluids with different fluid properties, like viscosity, surface tension, or density. Due to this wide range of different applications and demands on printheads it is important to investigate the influence of relevant factors on the droplet formation process. Therefore, the influence of the fluid properties, the printhead geometry, and the electrical excitation form on the droplet formation process are described in this project. In detail, the influence of the surface tension as well as the viscosity of the fluid, the nozzle length and its width, and the amplitude of the applied voltage at different pulse widths on the droplet characteristics are investigated. The used printhead consists of a silicon chip, which includes the fluidic components, and of a bimorph piezoelectric actuator. The printhead is manufactured with rapid manufacturing techniques, such as laser micromachining. The advantage of this method is that the printhead is adaptable to new boundary conditions in a time- and cost-saving manner. In this project, the nozzles have a square shape with a sidelength between 50 and 100 μm and the nozzle length varies between 50 and 200 μm. A fluid mixture is provided which can be varied in its fluid properties. Therefore, the possibility for the independent adjustment of its viscosity and its surface tension is given. The mixture consists of glycerin, distilled water, and isopropanol. An analytical description for each amount of its substances enables to provide a fluid with defined properties. Three kinds of experiments are carried out in order to determine the influence of the fluid properties, the printhead geometry, and the electrical excitation on the droplet formation process. The determination of the minimum excitation voltage needed for droplet ejection and the determination of the droplet volume and its velocity. The main results are: The higher the surface tension, viscosity, and nozzle length, the higher is the minimum excitation voltage. Furthermore, the droplet velocity decreases for an increased surface tension, viscosity, and nozzle length. On the other hand, the droplet velocity increases with an enlarged amplitude of the voltage and pulse width. The droplet volume increases for an increased surface tension, nozzle width, pulse width, and amplitude of the voltage. In general, the reasons for these correlations are the interaction between the strength of the pressure pulse, friction forces, fluidic resistances, and fluid properties. Overall, the possibility to achieve microdroplets made of different fluids and with a specific velocity and volume is described. Furthermore, a fluid mixture, which can be varied in its fluid properties, is presented.

scholarly journals Ink-jet Printing of YBa2Cu3O7 Superconducting Coatings and Patterns from Aqueous Solutions

2012 ◽  
Vol 1449 ◽  
Author(s):  
Isabel Van Driessche ◽  
Jonas Feys ◽  
Pieter Vermeir ◽  
Petra Lommens
Keyword(s):  
Coated Conductors ◽  
Proof Of Concept ◽  
Continuous Processing ◽  
Ink Jet Printing ◽  
On Demand ◽  
Drop On Demand ◽  
Novel Approach ◽  
Ink Jet ◽  
Fluid Properties ◽  
Jet Printing

ABSTRACTIn this paper, we combine the use of Drop-on-Demand (DOD) ink-jet printing with completely water- based inks as a novel approach to the CSD process for coated conductors. This method holds the promise of improved scalability due to lower ink losses, continuous processing and a drastically increased precursor lifetime due to the prevention of solvent evaporation and dust incorporation. Moreover, ink-jet printing has the potential to switch quite easily from continuous coatings to a multi-filamentary pattern, which is particularly important for alternating current (AC) or field applications of coated conductors. The fluid properties, often expressed with dimensionless constants, like the Reynolds and Weber numbers, for printable liquids were determined. For proof-of-concept, single crystals of SrTiO3 with a low mismatch towards YBCO, were used as substrates.

Investigation of the Hydrodynamics of Suspended Cells for Reliable Inkjet Cell Printing

2014 ◽  
Author(s):  
Eric Cheng ◽  
Ali Ahmadi ◽  
Karen C. Cheung
Keyword(s):  
High Speed ◽  
Cell Tracking ◽  
Droplet Formation ◽  
Vertical Position ◽  
Cell Behaviour ◽  
Nozzle Orifice ◽  
Cell Printing ◽  
Drop On Demand ◽  
Droplet Ejection ◽  
A Cell

Reliable inkjet drop-on-demand dispensing of cells has numerous applications including cell assays and tissue engineering. Previous work on inkjet cell printing has demonstrated that the cell count per droplet is inhomogeneous and does not follow the expected Poisson distribution. In the present work, the flow-induced cell behaviour is characterised to better understand the hydrodynamic mechanisms behind unreliable cell printing. A glass piezoelectric inkjet nozzle with an 80 μm diameter orifice is mounted on a PDMS cast which acts as a refractive index matching material for cell tracking through an inverted microscope. Droplet formation is achieved by a bipolar waveform. A high-speed camera focused on the centre plane of the nozzle captures images which are then analysed by a cell tracking algorithm to obtain the horizontal and vertical position of the cells over time. High-speed tracking of cells within a transparent inkjet nozzle revealed three possible cell behaviours caused by the formation and break-off of droplets. These behaviours are cell travel, cell ejection and cell reflection, determined as a function of the position of the cell at the onset of droplet formation. The first behaviour, cell travel, is characterised as the displacement of the cell towards the orifice during droplet formation followed by a small backwards motion due to the retracting meniscus after droplet pinch-off. Cell travel results in a net forward displacement of the cell towards the nozzle orifice. The second observed cell behaviour is cell ejection, where a cell is ejected with a droplet and can no longer be observed within the nozzle after the droplet break-off. The third observed cell behaviour is cell reflection. In this case, hydrodynamic forces produced during droplet ejection acts on the cell to move it further away from the nozzle orifice resulting in a net displacement of the cell away from the orifice after droplet ejection. Through the cell tracking information, it is hypothesized that cell reflection is caused by fluid flow reversal during the droplet ejection process. As a result of cell reflection, certain cells within a region close to the orifice will not be printed; instead they are pushed to a location further away from the orifice. Therefore, mapping of cell positions before droplet formation is performed to identify regions within the nozzle that exhibit a high probability of cell ejection and reflection. Overall, the results from this study will greatly contribute to our understanding of the cell printing process, which will allow us to optimize current inkjet systems for cell printing applications.

scholarly journals Microstructural Characterization of Pure Tin Produced by the Drop-on-Demand Technique of Liquid Metal Jetting

2019 ◽  
Vol 50 (9) ◽  
pp. 4000-4005 ◽  
Author(s):  
Yaakov Idell ◽  
Nicholas Watkins ◽  
Andrew Pascall ◽  
Jason Jeffries ◽  
Kerri Blobaum
Keyword(s):  
Liquid Metal ◽  
Microstructural Characterization ◽  
On Demand ◽  
Drop On Demand

A Pneumatic Drop-on-Demand Printing System With an Extended Printable Liquid Range

2015 ◽  
Vol 24 (4) ◽  
pp. 768-770 ◽  
Author(s):  
In Ho Choi ◽  
Young Kwon Kim ◽  
Sangmin Lee ◽  
Seung Hee Lee ◽  
Joonwon Kim
Keyword(s):  
On Demand ◽  
Drop On Demand ◽  
Printing System

Formulation of a ceramic ink for a wide-array drop-on-demand ink-jet printer

2003 ◽  
Vol 29 (8) ◽  
pp. 887-892 ◽  
Author(s):  
X. Zhao ◽  
J.R.G. Evans ◽  
M.J. Edirisinghe ◽  
J.H. Song
Keyword(s):  
On Demand ◽  
Drop On Demand ◽  
Ink Jet
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