• Journal of Institute of Control, Robotics and Systems
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• v.9 no.12
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• pp.984-993
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• 2003

In Gravure printing process, there are a lot of printing errors caused by expansion and contraction of printing materials and difficulty of printing of small letters, accordingly we cannot detect those errors with eyes. In this paper, we describe the algorithm which can detect small errors automatically in Gravure printing process and a real-time detection system adopting the algorithm. We present the Perimetric Mask algorithm that can eliminate tiny errors occurring near the contour of printing objects to achieve accurate inspection, and also construct an algorithm utilizing symmetry transform which can emphasize tiny errors to make a robust inspection system. We have made a system running in real-time and verified the efficiency of the algorithm.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.11.1-11.1
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• 2009

Bulk-heterojunction type organic photovoltaic cells have been remarkably improved due to the development of efficient donors and post treatment process. However, most of researchers have studied on the OPVs using spin-coating method during the past decade. To commercialize the OPVs, much cheaper printing process should be developed such as inkjet, screen, gravure, and so on. In this study, we have focused on the development of printing technology using Inkjet and Aerosol-Jet printing, which can offer reliable device performance. Finally, 4.5% power conversion efficiency can be achieved under AM 1.5 1sun light illumination, which is the highest value in printed OPVs. We reveal that substantial improvement can be realized by highly efficient bulk heterojunction after printing. Also, we can confirm these two printing methods are promising fabrication methods for large area OPVs. Also, flexible and large area (18 cm2) printed OPVs have been fabricated and device performance will be discussed in detail.

• Journal of the Korean Graphic Arts Communication Society
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• v.30 no.3
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• pp.45-56
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• 2012

Printing technology is accepted by appropriate technology that smart phones, tablet PC, display(LCD, OLED, etc.) precision recently in the electronics industry, the market grows, this process in the ongoing efforts to improve competitiveness through the development of innovative technologies. So printed electronics appeared by new concept. This technology development is applied on electronic components and circuits for the simplification of the production process and reduce processing costs. Low-temperature process making possible for widening, slimmer, lighter, and more flexible, plastic substrates, such as(flexible) easily by forming a thin film on a substrate has been studied. In the past, the formation of the electrode used a screen printing method. But the screen printing method is formation of fine patterns, high-speed printing, mass production is difficult. The roll-to-roll printing method as an alternative to screen printing to produce electronic devices by printing techniques that were used traditionally in the latest technology and processing techniques applied to precision control are very economical to implement fine-line printing equipment has been evaluated as. In order to function as electronic devices, especially the dozens of existing micro-level of non-dot print fine line printing is required, the line should not break at all, because according to the specifications required to fit the ink transfer conditions should be established. In this study of roll-to-roll printing conductive paste suitable for gravure offset printing by developing Ag paste for forming fine patterns to study the basic physical properties with the aim of this study were to.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.2 s.179
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• pp.181-190
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• 2006

In the industry, three-dimensional coloring has been needed for a realistic prototype. The Z-corporation developed a 3D printer which provides a three-dimensional colored prototype. However, the process cannot be adopted to models fabricated by other rapid prototyping processes. In addition, time and cost for manufacturing colored prototypes still remain to be improved. In this study, a new coloring process using an ink-jet head is proposed for color printing on a three-dimensional surface. Process parameters such as the angle and the distance between the ink-jet nozzle and the three-dimensional surface should be investigated through experiments. In order to minimize the distortion of a 2D image, the correction matrix according to the sloped angle is proposed and obtained by analysis of printing errors. An image on the doubly curved surface is printed so as to verify the proposed method. As a practical example, a helmet is chosen for printing images on the curved surface. The practical applicability of the correction matrix is then demonstrated by printing the character images on the surface of the helmet.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.113-118
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• 2020

The purpose of this study is to evaluate the shrinkage characteristics of the cement-based composite for 3D printing construction, and to evaluate the shrinkage before/after extrusion and after printing during the printing process. As a result of evaluating the compressive strength by curing age of OPC-mix and printing-mix, similar trends were shown until 7 days of age, but the maximum shrinkage of 252 ㎛/m was larger in the case of OPC-mix compared to printing-mix. During the printing process, the compressive strength of the cementitious composite material after extrusion was about 6.5 MPa lower than the material before extrusion until the 7th day of age, but the level of strength on the 28th day of age was similar. As for the shrinkage characteristics, the result of shrinkage after printing showed greater shrinkage in the range of 220-260 ㎛/m compared to the result of shrinkage before extrusion.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.103-109
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• 2010

An ink transfer is modeled and experimentally verified using roll-to-roll electric direct gravure printing process. The ink transfer model based on the physical mechanism for the maximum ink transfer rate is proposed, and experimented by the electric printing machine in FDRC for the relations of the maximum ink transfer rates to the printing pressure, the operating speed, the operating tension, the surface roughness of substrates, and the contact angle between substrate and silver ink. The free ink split coefficient and immobilized ink under the maximum ink transfer rate are calculated by the physical parameter in a printing process and contact angle between substrates and ink. Numerical simulations and experimental studies were carried out to verify performances of the proposed ink transfer model. Results showed that the proposed ink transfer model was effective for the prediction of the amount of transferred ink to the substrate in a direct gravure printing systems.

• Design & Manufacturing
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• v.12 no.3
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• pp.19-24
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• 2018

Fused deposition Modeling (FDM) is one of the most widely used for the prototype of parts at ease. The FDM 3D printing method is a lamination manufacturing method that the resin is melted at a high temperature and piled up one by one. Another term is also referred to as FFF (Fused Filament Fabrication). 3D printing technology is mainly used only in the area of prototype production, not in production of commercial products. Therefore, if FDM 3D printer is applied to the product process of commercial products when considered, the strength and dimensional accuracy of the manufactured product is expected to be important. In this study, the mechanical properties of parts made by 3D printing with FDM method were investigated. The aim of this work is to examine how the mechanical properties of the FDM parts, by changing of processing FDM printing direction and the height of stacking layer is affected. The effect of the lamination direction and the height of the stacking layer, which are set as variables in the lamination process, by using the tensile specimen and impact specimen after the FDM manufacturing process were investigated and analyzed. The PLA (Poly Lactic Acid) was used as the filament materials for the 3D printing.

• Journal of the Semiconductor & Display Technology
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• v.11 no.4
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• pp.43-48
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• 2012

The screen printing method is much used in the flat panel display field including the LCD, PDP, FED, organic EL, and etc. for forming the high precision micro-pattern. Also A number of studies of screen printing method has been conducted as the method for the cost down through the improvement of productivity. Because of being the dot printing method of the cylindrical shape not being the line printing method like the existing PDP barrier rib and phosphor, the pillar arrays using the screen printing method is deposited in the hemispherical type not being cylindrical shape in the existing printing process conditions. In this paper, the parameters were set on the screen printing device in order to deposit the cross-sectional shape with the cone or trapezoid shape of the pillar in depositing the pillars used the screen printing device for vacuum glazing. The cross-sectional shape slope of the pillar according to the parameters was measured. And analysis the effect of the screen printing process conditions on the cross-sectional shape slope of pillars based upon the result of being measured. The processing conditions were drawn to minimize the cross-sectional shape slope of pillar.

• Journal of the Korean Graphic Arts Communication Society
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• v.30 no.2
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• pp.35-45
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• 2012

Need color separation process to appear number of minimum printing plate waterway maximum printing color at printing process. This time, printing plate is separated three primary colors of C(cyan), M(magenta), Y(yellow). Appear all colors of printing such three primary colors. But, three primary color ink appears 100% dark gray that is not clean as chroma is neared color to 0 because is not pure. As well as, the ink area rate that is whole by over print amount increase of three primary is expanded. As a result, influence in secondary printablity set-off growth by inaccurate color reproduction and ink dry badness, trapping efficiency decline etc.. Apply ink saving method that is replaced as K ink in consisted dark color constituent because three primary colors are over print each other adding one more K(black) plate by method to improve these problem. Therefore, can reduce extension of the total ink area rate, and help in correct color appearance control. As well as, eco-friendly printing process attains improving printablity at the same time curtailment of printing expense by reducing requirement of total ink. Usually, there are UCR(under color removal) and GCR(gray component replacement) to ink saving application method. But, the practical use limit is insufficient state to tribe of technological investigation or field application about these method in domestic printing field. Therefore, in this research, ink saving been bringing by one method of eco-friendly printing confirmed that is applicable in usual domestic printing environment. Also, searched result getting in printablity by ink saving application.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.210.1-210.1
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• 2005