• Korean Journal of Materials Research
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• v.28 no.2
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• pp.95-100
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• 2018

In this study, $ZrO_2$ ceramic ink was formulated for additive manufacturing three dimensional structure using dispenser printing technique. Ceramic ink with various $ZrO_2$ loading (30, 40, 50vol%) was prepared to evaluate their rheological properties and printability. High $ZrO_2$ loading $ZrO_2$ ceramic ink showed higher elastic modulus and improved shape retention, when the ceramic ink was printed and sintered at $1450^{\circ}C$ for 1h. Microstructural analysis of printed $ZrO_2$ objective indicated that high $ZrO_2$ loading objective showed lower porosity and smaller pore size.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.4
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• pp.382-393
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• 2024

The Microplotter system with a fluid dispensing method, sprays fluid based on ultrasonic pumping through piezoelectric devices. This technique can possible for various materials with a wide range of viscosities to be printed in microscale. In this paper, we introduces dispenser printing technology as well as aim to understand and apply various processes using the equipment. In addition, we will explain how to optimize the equipment by adjusting parameters such as spray intensity, tip height during printing, and patterning speed. By utilizing Microplotter's advantage of being compatible with a wide range of fluids, including metal nanoparticles, carbon nanotubes, DNA, and proteins, it is expected to be used in various fields such as printed electronics, biotechnology, and chemical engineering.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.9
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• pp.787-792
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• 2015

Recently, 3D printing technology is a hot issue in various industrial fields. According to the user's application, it allows for the free form fabrication method to be utilized in a wide range. The powder based fusion technique is one of the 3D printing methods. When using this method it is possible to apply the various binder jetting techniques such as piezo, thermal bubble jet, dispenser and so on. In this paper, a multi thermal bubble ink jet was integrated for jetting of powder binding material and developing a power fused 3D printing system. For high quality 3D printing parts, it needs an analysis and evaluation of the behavior of the thermal bubble ink jet head. In the experiment, a correlation between jetting binder quantity and layer thickness of powder was investigated, and a 3D part model was fabricated, which was used by measuring the scale factor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.5
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• pp.365-372
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• 2017

Finger electrodes on a crystalline silicon solar cell are required to be constructed as narrow and thick as possible in order to minimize shading losses and electrical resistance. The most common means to construct high-aspect ratio finger electrodes has been screen-printing, but it has difficulty achieving fine finger electrodes because the as-printed finger width is generally wider by 1.3-2.2 times the screen opening width. Consequently, it requires an extremely small screen opening (below $30{\mu}m$) in order to achieve a finger width below $40{\mu}m$. However, the use of such a small screen opening could result in various problems, such as high printing pressure, defective transport of silver paste, and high electrical resistance due to unfavorable mesh marks left on the finger electrodes. In this study, dispensing printing with a screw pump is introduced as an alternative to conventional screen-printing and its unique traits in the front side metallization of crystalline silicon solar cells is discussed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1529-1535
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• 2010

For the reliable use of inkjet technology as patterning tools, the jetting of the inkjet dispenser needs to be monitored for real-time detection of any malfunction. We present a self-sensing circuit that can be used to detect jetting failure by measuring electrical signals only. In addition, practical problems involved in the monitoring of inkjets in multinozzle printheads are discussed. In the study, software was developed and presented to demonstrate the feasibility of the proposed method for detecting inkjet jetting failure in a printing system.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.913-919
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• 2012

This paper presents results for dispensing and measuring micro-particles using a pneumatic dispensing system. Particle-suspended liquid droplets were dispensed and analyzed quantitatively at various particle concentrations and applied pressures. By using a developed experimental setup, the number of particles and the particle volume ratio in sequentially dispensed droplets were measured. Hydrophilic and hydrophobic surfaces were tested to find a suitable surface for counting the number of particle. It was confirmed that the dispensed particles concentrated into the center of the droplet on the smooth CD surface after evaporation of liquid. As the applied positive pressure increased, the number of particles per droplet increased consistently and the volume fraction of particles remained constant.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.4 s.121
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• pp.333-341
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• 2007

Waveform design method for inkjet printing has been proposed tv pressure wave measurement. The pressure wane inside the inkjet dispenser can be effectively measured by current measurement due to self-sensing capability of PZT. The pressure wave measured from current was verified by commercially availablelaser vibrometer. In order to obtain high speed inkjet droplets, two pulse waveform was designed such that the pressure wane after droplet formation can be minimized.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.431-432
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• 2007

In this study, we used screen printing on the rear glass with silver electrodes, phosphor and a dielectric which is on the silver electrodes, and carried out firing in the temperature of $550^{\circ}C$, $570^{\circ}C$, $450^{\circ}C$ each. To seal the rear and top glass together, we used crystalline frit paste as a sealing material with dispenser and carried out firing up to $450^{\circ}C$. As using this panel, we focused on optimizing the condition which influences characteristics of discharging by the distance between electrodes, electrode structure, type and pressure of gases for FFL.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.300-307
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• 2022

Time-resolved serial femtosecond crystallography (TR-SFX) is a powerful technique for determining temporal variations in the structural properties of biomacromolecules on ultra-short time scales without causing structure damage by employing femtosecond X-ray laser pulses generated by an X-ray free electron laser (XFEL). The mixing rate of reactants and biomolecule samples, as well as the hit rate between crystal samples and x-ray pulses, are critical factors determining TR-SFX performance, such as accurate image acquisition and efficient sample consumption. We here develop two distinct sample delivery systems that enable ultra-fast mixing and on-demand droplet injecting via pneumatic application with a square pulse signal. The first strategy relies on inertial mixing, which is caused by the high-speed collision and subsequent coalescence of droplets ejected through a double nozzle, while the second relies on on-demand pneumatic jetting embedded with a 3D-printed micromixer. First, the colliding behaviors of the droplets ejected through the double nozzle, as well as the inertial mixing within the coalesced droplets, are investigated experimentally and numerically. The mixing performance of the pneumatic jetting system with an integrated micromixer is then evaluated by using similar approaches. The sample delivery system devised in this work is very valuable for three-dimensional biomolecular structure analysis, which is critical for elucidating the mechanisms by which certain proteins cause disease, as well as searching for antibody drugs and new drug candidates.