• Title, Summary, Keyword: Coating speed

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The Local Surface Strength Variation of Coated Papers during Printing (인쇄과정에서 코팅 용지의 국부적인 표면강도 변화에 관한 연구)

  • Youn, Jong-Tae
    • Journal of the Korean Printing Society
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    • v.22 no.2
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    • pp.101-110
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    • 2004
  • The local surface strength variation of coated papers were measured at various speeds on a number of coated paper samples to study the effects of speed and ink tack on coating pick. Coating pick phenomenon is observed in an ink transfer variation curve as a decrease in the slope of the curve. On the other hand, it causes an actual decrease in net ink transfer to paper with an increase in speed. The effect of speed on coating pick depends on ink tack, ink film thickness and surface properties of coating layer formation of paper. A novel device to measure the surface strength can rate the coating paper in a different order. Comparison are made between dry test of coating paper pick and wet coating pick test of printing in IGT printability tester. Coating formulation is the main key to prevent from coating pick. The binder level increases, the coating pick and the slop decrease. The piling on blanket in printing is a problem when the coating pick is occur on a local area rather than average surface strength of coated papers.

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Wear Behavior of TiN Coatings Deposited on High Speed Steel and Alloy Tool Steel (TiN 코팅된 고속도강과 합금공구강의 마멸거동)

  • 김석삼;서창민;박준목
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.3
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    • pp.705-712
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    • 1995
  • The wear characteristics and wear mechanisms in TiN coating deposited on high speed steel and alloy tool steel by ion plating were investigated. Pin on V-block wear tester was used for a wear test method. The specimen was composed of three kinds of high speed steel and alloy tool steel which had different hardness by changing the heat treating condition. Three kinds of coating thickness were also applied to each specimen. Microscopic observation of worn surfaces was made by SEM. The scratch test of coating surface by the ion plating showed that critical load to break the coating interface was greater than 50N. The critical load increased with both substrate hardness and coating thickness. The wear resistance of TiN coated high speed steel became 10 times greater than that of non-coated ones. SEM observation showed that leading edge of contact was compressive and trailing edge was under maximum tensile stress and then surface cracking broke out perpendicular to sliding direction.

Computer Simulation of Coating Behavior Including Air for Various Coater Geometries and Operational Conditions (코팅 공정에서 공기를 고려한 코터형상 및 운전조건에 따른 코팅현상 해석)

  • Kim, H.Y.;Lyu, M.Y.;Choi, J.G.
    • Transactions of Materials Processing
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    • v.18 no.2
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    • pp.156-159
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    • 2009
  • Slot coating has been wide spread in photo-resist coating on the glass for liquid crystal display. Die in slot coater consists of manifold and land. Material comes in inlet of the die and flow into the manifold and then flow out through the land. The coating thickness variations along the die length depend upon inside of die design such as manifold and die land. However the coating thickness variations along the moving direction(coating direction) of the coater depend upon the operational conditions of coater as well as die lip design. The coating behaviors including atmospheric air have been investigated in this study. Die geometries considered in this study were nozzle gap and length of the die lip. Coating gap and coating speed were the variables fur coating operational conditions. When the nozzle gap and length of die lip increased climbing effect of PR on the downstream die lip was reduced. Subsequently uniformity of coating thickness improved. Uniformity of coating thickness also enhanced as coating gap and coater speed increased. The uniformity of coating gap was related to the velocity vector distributions on the coating surface.

Fabrication of Fine PEDOT:PSS Stripes Using Needle Coating (Needle 코팅을 이용한 미세 PEDOT:PSS 스트라이프 제작)

  • Lee, Jinyoung;Park, Jongwoon
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.3
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    • pp.100-104
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    • 2019
  • We have investigated the feasibility of fabricating fine stripes using needle coating for potential applications in solution-processed organic light-emitting diodes (OLEDs). To this end, we have employed an aqueous poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) solution that has been widely used as a hole injection layer (HIL) of OLEDs and performed needle coatings by varying the process parameters such as the coating gap and coating speed. As expected, the stripe width is reduced with increasing coating speed. However, the central thickness of the stripe is rather increased as the coating speed increases, which is different from other coating processes such as slot-die and blade coatings. It is due to the fact that the meniscus formed between the needle tip and the substrate varies depending sensitively on the coating speed. It is also found that the stripe width and thickness are reduced with increasing coating gap. To demonstrate its applicability to OLEDs, we have fabricated a red OLED stripe and obtained light emission with the width of about 90㎛.

EFFECTS OF CONVERGENT ANGLE OF NOZZLE CONTRACTION ON HIGH-SPEED OPTICAL FIBER COATING FLOW (노즐 축소부 수렴각이 고속 광섬유 피복유동에 미치는 영향)

  • Park, S.;Kim, K.;Kwak, H.S.
    • Journal of computational fluids engineering
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    • v.21 no.4
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    • pp.11-18
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    • 2016
  • A numerical study is conducted on the optical fiber coating flow in a primary coating nozzle consisting of three major parts: a resin chamber, a contraction and a coating die of small diameter. The flow is driven by the optical fiber penetrating the center of the nozzle at a high speed. The axisymmetric two-dimensional flow and heat transfer induced by viscous heating are examined based on the laminar flow assumption. Numerical experiments are performed with varying the convergent angle of nozzle contraction and the optical fiber drawing speed. The numerical results show that for high drawing speed greater than 30 m/s, there is a transition in the essential flow features depending on the convergent angle. For a large convergent angle greater than $30^{\circ}$, unfavorable multicellular flow structures are monitored, which could be associated with wall boundary-layer separation. In the regime of small convergent angle, as the angle increases, the highest resin temperature at the exit of die and the coating thickness decrease but the sensitivity of coating thickness on drawing speed and the maximum shear strain of resin on the optical fiber increase. The effects of the convergent angle are discussed in view of compromise searching for an appropriate angle for high-speed optical fiber coating.

Dynamics and Instability of a Polymeric Paint in Roll Coating Process for Automotive Pre-coating Application (자동차 선도장을 위한 롤코팅 공정에서 고분자 도료의 동적 거동 및 불안정성)

  • Kim, Jin-Ho;Lee, In-Jun;Noh, Seung-Man;Kang, Choong-Yeol;Nam, Joon-Hyun;Jung, Hyun-Wook;Park, Jong-Myung
    • Polymer(Korea)
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    • v.35 no.6
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    • pp.574-579
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    • 2011
  • 3-Roll coating process as a key application technology for manufacturing automotive pre-painted metal-sheets has been studied. The 3-Roll coating system for this study consists of pick-up roll for picking up and distributing coating liquid from the reservoir, metering roll to properly meter coating liquid in metering gap regime, and applicator roll for directly transferring liquid into metal-sheet surface. Flow dynamics and operable coating windows of a polymeric paint (primer) with shear-thinning rheological property have been correlated with processing parameters such as speed ratio and metering gap between pick-up and metering rolls. In the uniform coating regime, dry coating thickness increased with increasing metering gap or decreasing speed ratio. Ribbing and cascade instabilities were observed in low speed and high speed ratio conditions, respectively. It is revealed that lower speed ratio makes severity and wavelength of the ribbing increase, aggravating flow instability in coating systems.

Coating Properties of a TPD Organic Hole-transporting Layer Deposited using a Continuous slot-die Coating Method (연속 slot-die 코팅법을 이용한 TPD 유기 정공수송층의 코팅 특성 분석)

  • Chung, Kook Chae;Kim, Young Kuk;Choi, Chul Jin
    • Korean Journal of Metals and Materials
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    • v.48 no.4
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    • pp.363-368
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    • 2010
  • N,N'-diphenyl-N,N'-bis(3-methylphenyl)1-1' biphenyl-4,4'-diamine (TPD) hole-transporting layers were deposited using a continuous slot-die coating method on ITO/PET flexible substrates. It is crucial that the substrates have a very smooth surface with a RMS roughness of less than 2 nm for the deposition of semiconductor nanocrystals or Quantum Dots. The parameters of the slot-die coating, including the solution concentration of the TPD, the gap between the slot-die and the substrates, and the coating speed were controlled in these experiments. To obtain full coverage of the TPD films on the ITO/PET substrates (40 mm wide and several meters long), the injection rates of the TPD solution were increased proportional to the coating speed of the flexible substrates. Additionally, the injection rates must be increased as the gap distance changes from 400 to 600 ${\mu}m$ at the same coating speed. A RMS surface roughness of less than 2 nm was obtained, in contrast to bare ITO/PET substrates, at 13 nm, as the coating speed and gap distance increased.

Tribological Behaviors Against Counterpart Materials of Ti-Si-N Coating Layers Prepared by a Hybrid Coating System (하이브리드 코팅시스템에 의해 제조된 Ti-Si-N 코팅막의 상대재에 대한 마모거동 연구)

  • 박옥남;박종현;윤석영;권식철;김광호
    • Journal of the Korean institute of surface engineering
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    • v.36 no.2
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    • pp.116-121
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    • 2003
  • Ti-Si-N coating layers were deposited onto WC-Co substrates by a hybrid system of arc ion plating (AIP) and sputtering techniques. The tribological behaviors of Ti-Si-N coating layers with various Si contents were investigated by the dry sliding wear experiments, which were conducted at three different sliding speeds, 0.1, 0.3, 0.5 m/s, against the steel and alumina balls. In the case of steel ball, the average friction coefficient slightly decreased with increasing the sliding speed regardless of Si content due to adhesive wear behavior between coating layer and steel ball. At constant sliding speed, the average friction coefficient decreased with increase of Si content. On the contrary, in the case of alumina ball, the average friction coefficient increased with increasing the sliding speed regardless of Si content, indicating that the abrasive wear behavior was more dominant when the coating layers slide against alumina ball. Through these experimental results, it was found that the tribological behaviors of Ti-Si-N coating layers were effected by factors such as Si content, sliding speed, and kinds of counterpart materials rather than the hardness of coating layer.

Effect of Applied Load and Sliding Speed on Wear Behavior of Thermally Sprayed STS316 Coating (STS316 용사코팅의 마모거동에 미치는 작용하중 및 미끄럼속도의 영향)

  • Lee, Jae-Hong;Kim, Yeong-Sik
    • Journal of Power System Engineering
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    • v.18 no.5
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    • pp.74-79
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    • 2014
  • This article aims at investigating the effect of applied load and sliding speed on wear behavior of thermally spraryed STS316 coating. STS316 coatings were fabricated by flame spray process according to optimal parameters on steel substrates. Dry sliding wear tests were performed on STS316 coating using four different applied load as 10, 15, 20 and 25 N and four different sliding speed as 15, 30, 45 and 60 rpm. Wear behavior on worn surface was investigated using scanning electron microscope(SEM) and energy disperive X-ray spectroscopy(EDS). The dominant wear mechanism of STS316 coating under low applied load and sliding speed was oxidation on worn surface. However, under high applied load and sliding speed the principal wear mechanism was abrasion on oxidation film and damage of oxidation film.

Studies on Relations between High Solid Coating and Quality Changes(II) - Effect of high solid coating on coated paper properties - (고농도 도공과 품질변화의 상관성 연구(2보) -도공지의 품질과 고농도 도공의 효과-)

  • Lee, Yong-Kyu;Yoo, Sung-Jong;Cho, Byoung-Uk;Kim, Yong-Sik
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.39 no.3
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    • pp.52-59
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    • 2007
  • This paper confirms that high solid coating can increase coating speed and reduce drying cost. Low solid coating color with the synthetic thickener and high solid coating color with the rheology modifier and with higher ratio of GCC were prepared. Coated paper was then produced with an industrial coater, varying coating speed and dryer temperature in order to keep the moisture content of the coated paper constant. Coating color concentration was able to be increased from 66% to 69% and from 68% to 71% without an adverse effect on coating color rheology. With a help of the rheology modifier, the increased ratio of GCC in high solid coating did not show harmful effects on the coated paper quality.