Shape Characterization for Droplet Impingement Dynamics in Ink-Jet Deposition

2012 ◽  
Author(s):  
Wenchao Zhou ◽  
Drew Loney ◽  
Andrei G. Fedorov ◽  
F. Levent Degertekin ◽  
David W. Rosen
Keyword(s):  
Deposition Process ◽  
Shape Evolution ◽  
Droplet Deposition ◽  
Droplet Spreading ◽  
Droplet Impingement ◽  
Droplet Shape ◽  
Part Quality ◽  
Ink Jet ◽  
Jet Printing ◽  
The Impact

The impact of droplets onto a substrate in ink-jet printing is critical for control and optimization of the droplet deposition process to improve part quality and accuracy and to reduce the manufacturing time. However, most previous research on droplet impingement dynamics mainly utilized one metric — the droplet spreading radius, which does not provide enough information for manufacturing purposes. This paper presents a new metric that is relevant to manufacturing by characterizing the droplet shape by measuring the similarity between the droplet shape and a desired shape over time. This enables a model of droplet shape evolution and optimization of the droplet deposition process to build desired geometries. Meanwhile, analyses with this shape metric aids understanding the physics of droplet shape evolution during impingement. A 2-D shape metric is first proposed and test cases are given to validate the effectiveness of the shape metric. Then the definition is extended to characterize 3-D droplet shape. Results also show the 3-D shape metric is effective and robust.

scholarly journals Droplet Impact on Suspended Metallic Meshes: Effects of Wettability, Reynolds and Weber Numbers

Fluids ◽  
2020 ◽  
Vol 5 (2) ◽  
pp. 81 ◽  
Author(s):  
Konstantinos Vontas ◽  
Cristina Boscariol ◽  
Manolia Andredaki ◽  
Anastasios Georgoulas ◽  
Cyril Crua ◽  
...  
Keyword(s):  
General Context ◽  
Liquid Penetration ◽  
Droplet Impingement ◽  
Textile Design ◽  
Lower Viscosity ◽  
Wide Range ◽  
Jet Printing ◽  
Break Up ◽  
Metallic Meshes ◽  
The Impact

Liquid penetration analysis in porous media is of great importance in a wide range of applications such as ink jet printing technology, painting and textile design. This article presents an investigation of droplet impingement onto metallic meshes, aiming to provide insights by identifying and quantifying impact characteristics that are difficult to measure experimentally. For this purpose, an enhanced Volume-Of-Fluid (VOF) numerical simulation framework is utilised, previously developed in the general context of the OpenFOAM CFD Toolbox. Droplet impacts on metallic meshes are performed both experimentally and numerically with satisfactory degree of agreement. From the experimental investigation three main outcomes are observed—deposition, partial imbibition, and penetration. The penetration into suspended meshes leads to spectacular multiple jetting below the mesh. A higher amount of liquid penetration is linked to higher impact velocity, lower viscosity and larger pore size dimension. An estimation of the liquid penetration is given in order to evaluate the impregnation properties of the meshes. From the parametric analysis it is shown that liquid viscosity affects the adhesion characteristics of the drops significantly, whereas droplet break-up after the impact is mostly controlled by surface tension. Additionally, wettability characteristics are found to play an important role in both liquid penetration and droplet break-up below the mesh.

Modelling of Droplet Deposition Shape on Fabric Surface using Spray Printing

2020 ◽  
Vol 7 (1) ◽  
pp. 37-45
Author(s):  
Yuan Xiao ◽  
Huanhuan Liu ◽  
Song Shen ◽  
Pengcheng Yang
Keyword(s):  
Bubble Formation ◽  
Deposition Process ◽  
Droplet Deposition ◽  
Two Phase ◽  
Droplet Spreading ◽  
Surface Deposition ◽  
Penetration Process ◽  
Drop On Demand ◽  
Fabric Surface ◽  
Droplet Spray

A droplet-impacted fabric surface deposition process was established based on the two-phase volume of fluid (VOF) computing model. This study was important because implementation of drop-on-demand 3D printing used for forming flexible conductive lines on fabric depends on understanding the droplet deposition mechanism. The interaction of droplets and the fabric substrate, as well as the penetration process, were simulated. The distribution of pressure and velocity, and the influence of surface tension and viscosity, in the droplet deposition process were also studied. The simulation and confirmatory experimental results show that the internal pressure gradient in the liquid was the main reason for the droplet spreading, penetration, and bubble formation. These research results lay a theoretical foundation for droplet spray printing of conductive lines on fabric surfaces.

The mechanism of a splash on a dry solid surface

2011 ◽  
Vol 690 ◽  
pp. 148-172 ◽  
Author(s):  
Shreyas Mandre ◽  
Michael P. Brenner
Keyword(s):  
Solid Surface ◽  
High Speed ◽  
Liquid Droplet ◽  
Contact Point ◽  
Quantitative Agreement ◽  
Gas Pressure ◽  
Liquid Viscosity ◽  
Ink Jet ◽  
Jet Printing ◽  
The Impact

AbstractFrom rain storms to ink jet printing, it is ubiquitous that a high-speed liquid droplet creates a splash when it impacts on a dry solid surface. Yet, the fluid mechanical mechanism causing this splash is unknown. About fifty years ago it was discovered that corona splashes are preceded by the ejection of a thin fluid sheet very near the vicinity of the contact point. Here we present a first-principles description of the mechanism for sheet formation, the initial stages of which occur before the droplet physically contacts the surface. We predict precisely when sheet formation occurs on a smooth surface as a function of experimental parameters, along with conditions on the roughness and other parameters for the validity of the predictions. The process of sheet formation provides a semi-quantitative framework for studying the subsequent events and the influence of liquid viscosity, gas pressure and surface roughness. The conclusions derived from this framework are in quantitative agreement with previous measurements of the splash threshold as a function of impact parameters (the size and velocity of the droplet) and in qualitative agreement with the dependence on physical properties (liquid viscosity, surface tension, ambient gas pressure, etc.) Our analysis predicts an as yet unobserved series of events within micrometres of the impact point and microseconds of the splash.

Freeform Fabrication of Ceramics by Hot-Melt Ink-Jet Printing

2000 ◽  
Vol 625 ◽  
Author(s):  
B. Derby ◽  
N. Reis ◽  
K.A.M. Seerden ◽  
P.S. Grant ◽  
J.R.G. Evans
Keyword(s):  
Melting Point ◽  
Deposition Process ◽  
Layer Growth ◽  
Ink Jet Printing ◽  
Freeform Fabrication ◽  
Ink Jet ◽  
Ceramic Components ◽  
Fluid Properties ◽  
Jet Printing ◽  
Hot Melt

AbstractInk-jet printing is a versatile freeform fabrication technique with a high spatial resolution. By suspending ceramic particles in low melting point organic materials and printing above the melting point, rapid cooling on impact after printing results in rapid layer growth. Current results from a collaborative programme studying the hot wax ink-jet printing of structural ceramic components will be reported. The influence of key fluid properties on the ink-jet deposition process are discussed.

scholarly journals Experimental study on two consecutive droplets impacting onto an inclined solid surface

2021 ◽  
Vol 37 ◽  
pp. 432-445
Author(s):  
Chun-Kuei Chen ◽  
Sheng-Qi Chen ◽  
Wei-Mon Yan ◽  
Wen-Ken Li ◽  
Ta-Hui Lin
Keyword(s):  
Solid Surface ◽  
Contact Angles ◽  
Maximum Height ◽  
Droplet Spreading ◽  
Droplet Impingement ◽  
Impact Phenomena ◽  
The Moment ◽  
The Impact ◽  
Inclined Surface ◽  
Surface Angle

Abstract The present study is concerned with the experimental impingement of two consecutive droplets on an inclined solid surface. Attention is mainly paid to the effects of impingement timing with various oblique angles (Φ) of the surface on the impact phenomena, which mainly affect the maximum droplet spreading diameter. The investigation considers four impingement scenarios differentiated by impingement timing, namely Case 1: single-droplet impingement; Case 2 of Δt1: the moment when the leading droplet starts spreading along the oblique surface; Case 3 of Δt2: the moment when the leading droplet reaches its maximum spreading; and Case 4 of Δt3: the moment when the leading droplet starts retracting. It is observed that deformation behavior of two successive droplets impacting on the inclined surface experiences a complex asymmetric morphology evolution due to the enhancement of gravity effect and various conditions of the impingement timing. The merged droplet becomes slender with increasing oblique surface angle in the final steady shape, causing the decrease in the value of front and back contact angles. The impingement timing has a significant influence on the change of the maximum height of the merged droplet. The coalesced droplet spreads to the maximum dimensionless width diameter at Δt = Δt2 and the oblique angle of Φ = 45°, but reaches the maximum dimensionless height for Δt = Δt2 at Φ = 30°. The front contact angles converge to a fixed value eventually for all conditions of impingement timing, and the values become lower with the increasing surface inclination.

Dynamic Model for Flow and Droplet Deposition in Direct Ceramic Ink-jet Printing

2004 ◽  
Vol 54 (1) ◽  
pp. 85-93 ◽  
Author(s):  
Vijay Soundararajan Mythili ◽  
K. Prakasan
Keyword(s):  
Dynamic Model ◽  
Droplet Deposition ◽  
Ink Jet Printing ◽  
Ink Jet ◽  
Jet Printing

Contact time of impacting droplets on a superhydrophobic surface with tunable curvature and groove orientation

2021 ◽  
Author(s):  
Chunfang Guo ◽  
Lei Liu ◽  
Changwan Liu
Keyword(s):  
Weber Number ◽  
Contact Time ◽  
Superhydrophobic Surface ◽  
The Other ◽  
Impact Dynamics ◽  
Azimuthal Direction ◽  
Droplet Spreading ◽  
Droplet Impingement ◽  
Practical Applications ◽  
The Impact

Abstract Regulating the impact dynamics of water droplets on a solid surface is of great significance for some practical applications. In this study, the droplet impingement on a flexible superhydrophobic surface arrayed with micro-scale grooves is investigated experimentally. The surface was curved into cylindrical shapes with certain curvatures from two orthogonal directions, where axial and circumferential grooves were formed, respectively. The effects of curvature diameter and Weber number, as well as the orientation of grooves on droplet spreading and retracting dynamics were discussed and explained. Results show that the circumferential grooves promote the spreading of droplet in the azimuthal direction, where the droplet rebounds from the surface with a stretched shape. This mechanism further reduces the contact time of impacting droplets on the superhydrophobic surface compared to the other curving mode.

Relationship between silk fabric pretreatment, droplet spreading, and ink-jet printing accuracy of reactive dye inks

2018 ◽  
Vol 135 (45) ◽  
pp. 46703 ◽  
Author(s):  
Min Li ◽  
Liping Zhang ◽  
Yajie An ◽  
Wujun Ma ◽  
Shaohai Fu
Keyword(s):  
Reactive Dye ◽  
Silk Fabric ◽  
Droplet Spreading ◽  
Ink Jet Printing ◽  
Ink Jet ◽  
Jet Printing

Shape evolution of multiple interacting droplets in inkjet deposition

2015 ◽  
Vol 21 (4) ◽  
pp. 373-385 ◽  
Author(s):  
Wenchao Zhou ◽  
Drew Loney ◽  
Andrei G. Fedorov ◽  
F. Levent Degertekin ◽  
David W. Rosen
Keyword(s):  
Deposition Process ◽  
Simulation Tool ◽  
Droplet Deposition ◽  
Interface Dynamics ◽  
Interface Evolution ◽  
Content Type ◽  
Ink Jet ◽  
Numerical Solver ◽  
And Control ◽  
Manufacturing Time

Purpose – The aim of this paper is to advance the understanding of the droplet deposition process to better predict and control the manufacturing results for ink-jet deposition. Design/methodology/approach – As material interface has both geometric and physical significance to manufacturing, the approach the authors take is to study the interface evolution during the material joining process in ink-jet deposition using a novel shape metric and a previously developed powerful simulation tool. This tool is an experimentally validated numerical solver based on the combination of the lattice Boltzmann method and the phase-field model that enabled efficient simulation of multiple-droplet interactions in three dimensions. Findings – The underlying physics of two-droplet interaction is carefully examined, which provides deep insights into the effects of the printing conditions on the interface evolution of multiple-droplet interaction. By studying line printing, it is found that increasing impact velocity or decreasing fluid viscosity can reduce manufacturing time. For array printing, the authors have found the issue of air bubble entrapment that can lead to voids in the manufactured parts. Research limitations/implications – The array of droplets impinges simultaneously, in contrast to most ink-jet printers. Sequential impingement of lines of droplet needs to be studied. Also, impingement on non-planar surfaces has not been investigated yet, but is important for additive manufacturing. Finally, it is recognized that the droplet hardening mechanisms need to be incorporated in the simulation tool to predict and control the final shape and size of the arbitrary features and manufacturing time for ink-jet deposition. Practical implications – The research findings in this paper imply opportunities for optimization of printing conditions and print head design. Furthermore, if precise droplet control can be achieved, it may be possible to eliminate the need for leveling roller in the current commercial printers to save machine and manufacturing cost. Originality/value – This work represents one of the first attempts for a systematic study of the interface dynamics of multiple-droplet interaction in ink-jet deposition enabled by the novel shape metric proposed in the paper and a previously developed numerical solver. The findings in this paper advanced the understanding of the droplet deposition process. The physics-based approach of analyzing the simulation results of the interface dynamics provides deep insights into how to predict and control the manufacturing relevant outcomes, and optimization of the deposition parameters is made possible under the same framework.

Preliminary Study of Printing Optical-Based Materials using Aerosol Jet Deposition Process

2018 ◽  
Vol 8 (3) ◽  
Author(s):  
Aleksandra Fortier ◽  
Max Tsao ◽  
Nick D. Williard ◽  
Yinjiao Xing ◽  
Michael G Pecht
Keyword(s):  
Fiber Optic ◽  
Deposition Process ◽  
Processing Parameters ◽  
Bragg Grating ◽  
Sem Images ◽  
Jet Printing ◽  
Aerosol Jet Deposition ◽  
Printing Ink ◽  
The Impact ◽  
Aerosol Jet Printing

This work examines the printing of optical-based materials using aerosol jet printing (AJP), an additive manufacturing process. Deposition of optical-based materials using the AJP process has potential to be applied in the fabrication of embedded fiber optic Bragg grating sensors. Made from silica (SiO2), fiber optic Bragg grating sensors are small, lightweight, and chemically inert, making them suitable for a variety of applications. This study examines the preparation and deposition of a newly developed silica-based printing ink. The results of the printing method, the impact of various printing and processing parameters on the deposition quality and microstructure, light reflectivity, scanning electron microscope (SEM) images, and content analyses of the deposited layers are presented. The results show uniform printed layers and demonstrate the capability of the AJP method as well as the newly developed silicabased ink to print high-quality commercial optical-based materials. The focus of this study is on the process/ optical material property interaction only; the printing of actual functional sensors on components and testing them will be discussed in later studies and is beyond the scope of this paper.

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