• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.937-945
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• 2015

In this paper, we study the coating performance according to the slot-die conditions in the coating process. The quality of the slot-die coating depends on factors such as feeding speed of film, the viscosity of liquid, and the pressure applied to the slot-die. In this study, we determine the optimum conditions for a stable coating by performing 2-D and 3-D simulations. We carry out numerical simulations with respect to the feeding velocity of the film, the pressure of the slot-die inlet, and the viscosity of the coating liquid. Based on the results, the coating was the most reliable when the pressure of the inlet was $5kgf/cm^2$, the viscosity was about 100 cps and the velocity was 20 m/min.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.918-925
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• 2021

The perovskite solar cell is a next-generation solar cell that replaces the existing silicon solar cell. It is a solar cell device using an organic-inorganic hybrid material having a perovskite structure as a photoactive layer. It has advantages for the process and has shown rapid efficiency improvement over the past decade. In the process of commercialization of such perovskite solar cells, research and development for a large-area coating method should be carried out. As one of the large-area perovskite solar cell large-area coating methods, the slot-die coating method was studied. By using a meniscus to pass over the substrate and coating the solution, the 3D printer was equipped with a meniscus so that it could be coated. Variables that act during coating include bed temperature, coating speed, N₂ blowing interval, N₂ blowing height, N₂ blowing intensity, etc. By controlling these, the perovskite absorption layer was manufactured and the coating conditions for manufacturing large-area devices were optimized.

• The monthly packaging world
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• s.351
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• pp.60-70
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• 2022

• Elastomers and Composites
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• v.48 no.4
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• pp.282-287
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• 2013

Slot coating has been widely spread in photo resist coating on glass for flat display monitor. High quality of coating is required as high quality of image in display is needed. Coating quality in the slot coating is divided into nozzle direction quality and machine direction quality. Nozzle direction quality is related to flow uniformity inside the die whereas machine direction quality is related to die lip design and operational conditions. In this study coating uniformity in the machine direction of slot coating has been investigated through computer simulation. Die lip angle and die lip length were considered as outside die geometry and coating speed was considered as operational condition. Coating behavior has been analyzed and coating quality has been evaluated through computer simulation. Coating thickness decreased and coating uniformity increased as coating speed increased. However, the stability of meniscus formation was reduced and subsequently coating stability was reduced as coating speed increased. Coating thickness deviation decreased as die lip angle increased in down stream die. Coating thickness decreased and time to reaching steady state increased as increased die lip length in down stream die.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.6
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• pp.491-495
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• 2014

We developed a compact high-precision slot-die coating machine for thin-film deposition on a flexible substrate. For smooth and precise coating, air-bearing and linear motor system were employed to minimize velocity ripple. The gap control mechanism is specially designed to have repeatability of gap between nozzle and substrate under 1 ${\mu}m$. Due to extremely precise gap control, the machine can coat thin-films down to 50 nm with $200mm{\times}100mm$ size. A thin film of Ag nano-particle ink is coated for demonstration.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.23-29
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• 2013

Recent advances in printing technology have increased the productivity of the roll-to-roll (R2R) printing process for printed circuitry. In the R2R printed electronics, characteristics of printed and coated layers are one of the most important issues that determine the functional quality of final products. The slot-die technology can coat a large area with high uniformity using low-viscosity materials; determining the process parameters is important to obtain excellent coating qualities. In this study, a viscocapillary model was used to predict qualities of coated layers and patterns. On the basis of analysis results, a novel meta model was derived using design of experiment methodology to improve accuracy. Sensitivity analysis was performed to define major parameters in R2R slot-die coating process. The coating speed was found to most significantly affect the coated layer thickness and was easily controlled. The performance of the proposed model is verified through experimental studies. Based on the statistical analysis results, R2R slot die process can be optimized to guarantee a desired thickness.

• Broadcasting and Media Magazine
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• v.20 no.2
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• pp.16-26
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• 2015

최근 다양한 유연 소재 기반의 전자 기기들이 개발 혹은 판매되고 있으며 이러한 전자 기기들에게 유연 소자 및 이를 구현하기 위한 공정 시스템은 필수적이라 할 수 있다. 본 논문에서는 인쇄전자 기술을 이용한 다양한 공정 기술과 이를 이용한 공정 시스템에 대해 논의한다. 인쇄전자 기술 중의 대표적인 코팅 기술로 마이크로 그라비어, 슬롯다이, 바 코팅 등의 기술이 있으며, 인쇄 기술로는 그라비어 옵셋, 열형 롤 임프린팅 기술 등이 있다. 최종적으로 이러한 각각의 공정 특성을 통합한 복합 멀티 롤투롤 공정 코팅 기술을 이용하여 다양한 유연 소자에 대응하는 소재의 생산이 가능하다.

• Polymer(Korea)
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• v.38 no.5
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• pp.640-644
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• 2014

As a process of plat panel display production, slot coating is widely used for the coating of photoresist on a wide glass substrate. A uniform coating thickness is important, and the coating uniformity is divided into nozzle and machine directions. The machine and nozzle directions coating uniformities are influenced by the operation condition of coater and flow uniformity inside the die, respectively. Non-uniform coating during steady coating process occurs according to those factors, however, non-uniform coating along the machine and nozzle directions has been observed at the beginning of coating by unsteady flow. In this study, steady and unsteady state flow simulations have been performed and compared with experiment to examine the causes of non-uniform coating. Computational results exhibited that it took a time to get a uniform pressure distribution at whole inside the die, and during this period of time edge regions showed lower exit velocity compared with center region. Subsequently edge regions had thinner coated layers than center region. However edge regions showed higher exit velocity than center region after steady state, and this made edge regions had thicker coated layer than center region.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.2
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• pp.159-166
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• 2015

Slot-die coating is well known technique to guarantee a uniformly coated layer and is compatible with roll-to-roll process. In actual roll-to-roll slot-die coating process, the lateral difference of coated layer thickness is observed. An experimental study was performed to improve the coating quality. Coating speed and coating gap were selected as the experimental factors. A full factorial, statistical method was conducted to optimize the process conditions. Based on the results of repeated experiment, the lowest deviation of lateral thickness (700 nm, <10%) was achieved at 10 m/min coating speed and $300{\mu}m$ coating gap. This result has significance because such optimized process guideline can be utilized with all process improvement in various coating applications.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.8
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• pp.611-616
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• 2016

Computational fluid dynamic simulation based on the ABAQUS software was conducted to observe the inside flow of slot-die nozzle. The slot-die nozzle was modeled as 3-dimensional structure and three significant parameters were determined: inlet velocity of fluid, reservoir angles, number of strips none of which have been mentioned previously in the literature. The design of experiment, full factorial analysis was performed within determined design and process levels. The simulation result shows the inlet fluid velocity is most significant factor for the flows of inside nozzle. As an interaction effect, reservoir angle is closely related with number of strip that should address when the nozzle is designed. Moreover, the optimized values of each determined parameter were obtained as 35 mm/s of inlet velocity, 3 of strip numbers, and $22^{\circ}$ of reservoir angles. Based on these parameters, the outlet velocity was obtained as 0.53% of outlet uniformity which is improved from 8.67% of nominal results.