scholarly journals Simulation study of droplet formation in inkjet printing using ANSYS FLUENT

2022 ◽  
Vol 2161 (1) ◽  
pp. 012026
Author(s):  
Neha Thakur ◽  
Hari Murthy

Abstract Flow simulations of jetting of inkjet drops are presented for water and ethylene glycol. In the inkjet printing process, droplet jetting behaviour is the deciding parameter for print quality. The multiphase volume of fluid (VOF) method is used because the interaction between two phases (air and liquid) is involved in the drop formation process. The commercial inkjet printer has a nozzle diameter of ∼73.2μm. In this work, a simulation model of inkjet printer nozzles with different diameters 40μm, 60μm, and 80μm are developed using ANSYS FLUENT software. It is observed that when water is taken as solvent then the stable droplets are generated at 60μm nozzle diameter till 9μs because of its low viscosity. For higher diameter, the stamen formation is observed. Ethylene glycol stable droplets are achieved at 80μm nozzle diameter till 9μs because of their high viscosity (∼10 times that of water). Along with the droplet formation, the sustainability of the droplet in the air before reaching the substrate is also important. The simulation model is an inexpensive, fast, and flexible alternative to study the ink characteristics of the real-world system without wasting resources.

2020 ◽  
Vol 2020 (15) ◽  
pp. 349-1-349-9
Author(s):  
Daulet Kenzhebalin ◽  
Baekdu Choi ◽  
Sige Hu ◽  
Yin Wang ◽  
Davi He ◽  
...  

Inkjet printer motor control consists of moving the printhead in the scan direction and in the process direction. Both movements have different objectives. Scan direction movement needs to have constant velocity and process direction movement needs to have accurate movement. In this paper, we discuss a method for controlling the velocity of the printhead and how to tune the motor control parameters. We also design six test pages for testing accuracy of the printhead movement and cartridge properties. For each test page, we discuss expected prints, common printer control problems that could alter the print quality, and how to identify them.


2020 ◽  
pp. 152808372097134
Author(s):  
Sherif M Youssef ◽  
M Megahed ◽  
Soliman S Ali-Eldin ◽  
MA Agwa

Vacuum resin infusion (VRI) is a promising technique for manufacturing complicated structural laminates. This high viscosity of nanofilled resin increases the filling time and leads to an incomplete mold filling. The mold filling time can be reduced either by making the fiber dimensions smaller than the mold (gaps around the fibers) or by adding ethanol to nanofilled epoxy. However, ethanol addition influences the mechanical properties of composite laminates. In this study, different amounts of ethanol (0.5 wt. % and 1 wt. %) were used as a diluent to both neat epoxy and epoxy filled with (0.25 wt. %) of titanium dioxide (TiO2) nanoparticles. From results, it was found that ethanol addition saves the time for neat and nanofilled epoxy by 47.1% and 24.1%, respectively. It was found that adding 0.5 wt. % of ethanol to 0.25wt. % of TiO2 nanoparticles (GT0.25E0.5) enhances the tensile and flexural strength by 30.8% and 55.9%, respectively compared with neat specimens. Furthermore, the tensile and flexural moduli increased by 62% and 72.3%, respectively. Furthermore, the mold filling time was investigated experimentally and validated numerically using ANSYS FLUENT software. The mold filling time prediction using ANSYS FLUENT can be used to avoid resin gelation before the incomplete mold filling and thus can be considered a cost-effective methodology. The results showed that the gaps around the fibers reduce the time by 178% without affecting the mechanical properties.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 338
Author(s):  
Ali Alrahlah ◽  
Abdel-Basit Al-Odayni ◽  
Haifa Fahad Al-Mutairi ◽  
Bashaer Mousa Almousa ◽  
Faisal S. Alsubaie ◽  
...  

This study aimed to synthesize new bisphenol A-glycidyl methacrylate (BisGMA) derivatives, targeting a reduction in its viscosity by substituting one of its OH groups, the leading cause of its high viscosity, with a chlorine atom. Hence, this monochloro-BisGMA (mCl-BisGMA) monomer was synthesized by Appel reaction procedure, and its structure was confirmed using Fourier transform infrared spectroscopy, 1H and 13C-nuclear magnetic resonance spectroscopy, and mass spectroscopy. The viscosity of mCl-BisGMA (8.3 Pa·s) was measured under rheometry conditions, and it was found to be more than 65-fold lower than that of BisGMA (566.1 Pa·s) at 25 °C. For the assessment of the viscosity changes of model resins in the presence of mCl-BisGMA, a series of resin matrices, in which, besides BisGMA, 50 wt % was triethylene glycol dimethacrylate, were prepared and evaluated at 20, 25, and 35 °C. Thus, BisGMA was incrementally replaced by 25% mCl-BisGMA to obtain TBC0, TBC25, TBC50, TBC75, and TBC100 blends. The viscosity decreased with temperature, and the mCl-BisGMA content in the resin mixture increased. The substantial reduction in the viscosity value of mCl-BisGMA compared with that of BisGMA may imply its potential use as a dental resin matrix, either alone or in combination with traditional monomers. However, the various properties of mCl-BisGMA-containing matrices should be evaluated.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 586
Author(s):  
Ana-Gianina Gereanu ◽  
Camillo Sartorio ◽  
Aurelio Bonasera ◽  
Giuliana Giuliano ◽  
Sebastiano Cataldo ◽  
...  

This work deals with the interfacial mixing mechanism of picoliter (pL)-scale droplets produced by sequential inkjet printing of organic-based inks onto ITO/PET surfaces at a moderately high Weber number (~101). Differently from solution dispensing processes at a high Bond number such as spin coating, the deposition by inkjet printing is strictly controlled by droplet velocity, ink viscosity, and surface tension. In particular, this study considers the interfacial mixing of droplets containing the most investigated donor/acceptor couple for organic solar cells, i.e., poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM), showing how low-viscosity and low-surface energy inks can be leveraged for the fabrication of an interface suitable for a pseudo-planar heterojunction (pseudo-PHJ) organic solar cell (OSC) that is a convenient alternative to a bulk heterojunction (BHJ) OSC. The resulting thin-film morphology and molecular organization at the P3HT/PCBM interface are investigated, highlighting the roles of dissolution-driven molecular recirculation. This report represents a first step toward the sequential inkjet printing fabrication of pseudo-PHJ OSCs at low consumption of solvents/chemicals.


Aerospace ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Sicong Yu ◽  
Xufeng Zhang ◽  
Xiaoling Liu ◽  
Chris Rudd ◽  
Xiaosu Yi

In this concept-proof study, a preform-based RTM (Resin Transfer Molding) process is presented that is characterized by first pre-loading the solid curing agent onto the preform, and then injecting the liquid nonreactive resin with an intrinsically low viscosity into the mold to infiltrate and wet the pre-loaded preform. The separation of resin and hardener helped to process inherently high viscosity resins in a convenient way. Rosin-sourced, anhydrite-cured epoxies that would normally be regarded as unsuited to liquid composite molding, were thus processed. Rheological tests revealed that by separating the anhydrite curing agent from a formulated RTM resin system, the remaining epoxy liquid had its flowtime extended. C-scan and glass transition temperature tests showed that the preform pre-loaded with anhydrite was fully infiltrated and wetted by the liquid epoxy, and the two components were diffused and dissolved with each other, and finally, well reacted and cured. Composite laminates made via this approach exhibited roughly comparable quality and mechanical properties with prepreg controls via autoclave or compression molding, respectively. These findings were verified for both carbon and ramie fiber composites.


2014 ◽  
Vol 783-786 ◽  
pp. 2537-2540 ◽  
Author(s):  
Satoshi Sunada ◽  
Norio Nunomura ◽  
Sayaka Hirata ◽  
Naoki Nagase

Since Fe-Cu-C sintered steels are easily rusted, they are coated with rust preventive oils. High viscosity of those rust preventive oils decrease workability, and low viscosity deteriorates rust preventive performance. Therefore, it is necessary to develop new rust preventive oils with contradictory properties of low viscosity and superior rust prevention. However, precise methodology to evaluate rust prevention ability has not been established. In this study, we developed new technique to quantitatively evaluate rust prevention ability by measuring the open circuit potential through thin corrosive solution on Fe-Cu-C sintered steels coated with a rust preventive oils. As a result, the ability for rust prevention can be measured quantitatively, and it decreases slowly over time, with repeating destruction and restoration. Furthermore, it was found that the deteriorating processes of rust prevention ability for rust prevention oils are composed of three characteristics steps respectively. That is, in the first step the great open circuit potential changes from 0V to-0.3V with repetition were observed where the excellent rust prevention ability was kept, in the second step it decreases slowly from-0.1V to-0.4V with oscillation of the small potential changes where the gradual decrease of rust prevention ability was recognized and in the third step it decreases monotonously in the lower potential than-0.4V where the rust was observed because of the remarkable deteriorating of the rust prevention ability.


Author(s):  
K. R. Mrinal ◽  
Md. Hamid Siddique ◽  
Abdus Samad

A progressive cavity pump (PCP) is a positive displacement pump and has been used as an artificial lift method in the oil and gas industry for pumping fluid with solid content and high viscosity. In a PCP, a single-lobe rotor rotates inside a double-lobe stator. Articles on computational works for flows through a PCP are limited because of transient behavior of flow, complex geometry and moving boundaries. In this paper, a 3D CFD model has been developed to predict the flow variables at different operating conditions. The flow is considered as incompressible, single phase, transient, and turbulent. The dynamic mesh model in Ansys-Fluent for the rotor mesh movement is used, and a user defined function (UDF) written in C language defines the rotor’s hypocycloid path. The mesh deformation is done with spring based smoothing and local remeshing technique. The computational results are compared with the experiment results available in the literature. Thepump gives maximum flowrate at zero differential pressure.


2021 ◽  
Vol 1028 ◽  
pp. 346-351
Author(s):  
Soni Setiadji ◽  
Zulfi Mofa Agasa ◽  
Diba G Auliya ◽  
Fitrilawati ◽  
Norman Syakir ◽  
...  

Duration of use and injectability are external factors for Polydimethylsiloxane (PDMS) that needs to be considered when PDMS utilized as a vitreous substituted liquid in vitreoretinal surgery. In general, PDMS which has been used as a substitute for vitreous humour is PDMS with a low viscosity in the value about 1000 cSt and a high viscosity at a value of about 5000 cSt. Various deficiencies have been encountered from low and high viscosity of PDMS, causing research to be continued to obtain PDMS which has suitable properties as a substitute for vitreous humour. One of them is research to obtain medium viscosity of PDMS with a viscosity value of about 2000 cSt. Here, we reported synthesis and characterization of PDMS with medium viscosity in ranges from 1800 to 2600 mPas. PDMS was synthesized through Ring-Opening Polymerization (ROP) pathway using the monomer of Octamethylcyclotetrasiloxane (D4) and the chain terminator of Hexamethyldisiloxane (MM). Various concentrations of potassium hydroxide (KOH) of 3, 4, 6 and 8 %(w/v) were applied as initiator to form gel of PDMS. All synthesized PDMS samples were identified to have viscosity values of 1800-2600 mPas, refractive index values of 1.4042-1.4044 and surface tension values of 22-23 mN/m. Meanwhile, the results of Fourier-Transform Infrared (FTIR) measurement showed that the absorption peaks were similar to that of our previous report.


2021 ◽  
Author(s):  
KR Kantovitz ◽  
LL Cabral ◽  
NR Carlos ◽  
AZ de Freitas ◽  
DC Peruzzo ◽  
...  

SUMMARY The aim of this in vitro study was to quantitatively evaluate the internal gap of resin composites of high-and low-viscosity used in single- and incremental-fill techniques in Class I cavities exposed to thermal cycling (TC) using optical coherence tomography (OCT). Cavities of 4-mm depth and 3-mm diameter were prepared in 36 third molars randomly distributed into four groups, according to viscosity of restorative resin-based composite (high or low viscosity, all from 3M Oral Care) and technique application (bulk or incremental fill) used (n=9): RC, high-viscosity, incremental-fill, resin-based composite (Filtek Z350 XT Universal Restorative); BF, high-viscosity, bulk-fill, resin-based composite (Filtek One Bulk Fill); LRC, low-viscosity, incremental-fill, resin-based composite (Filtek Z350 XT Flowable Universal Restorative); and LBF, low-viscosity, bulk-fill, resin-based composite (Filtek Flowable Restorative). Single Bond Universal Adhesive system (3M Oral Care) was used in all the experimental groups. The incremental-fill technique was used for RC and LRC groups (2-mm increments), and a single-layer technique was used for BF and LBF groups, as recommended by the manufacturer. The internal adaptation of the resin at all dentin walls was evaluated before and after TC (5000 cycles between 5°C and 55°C) using OCT images. Five images of each restored tooth were obtained. Images were analyzed using ImageJ software that measured the entire length of the gaps at the dentin–restoration interface. The length of gaps (μm) was analyzed using two-way repeated measures ANOVA and the Tukey tests (α=0.05). There was a significant interaction between material types and TC (p=0.006), and a significant difference among all material types (p<0.0001), before and after TC (p<0.0001). Increased internal gaps at the dentin–restoration interface were noticed after TC for all groups. RC presented the lowest value of internal gap before and after TC, while LBF showed the highest values of internal gap after TC. In conclusion, TC negatively affected the integrity of internal gap, whereas high-viscosity, incremental-fill, resin-based composite presented better performance in terms of internal adaptation than low-viscosity, bulk-fill materials in Class I cavities.


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