• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.56-59
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• 2009

Roll forming process is one of important metal processing technology because the process is simple and economical. These days, roll forming process is tried to be employed in manufacturing the circuit board, barrier ribs and solar cell plate for productivity. However, it is difficult to apply to the forming of micro scale or sub-micro scale pattern. In this study, the roll forming processing for the micro scale is designed and analyzed. In this study, the forming of micro pattern for solar cell plate by incremental roll forming process is analyzed. The solar cell plate may have thousands of patterns, and the analysis of forming considering all the patterns is impossible due to the computational costs. In this study, analyses are carried out for various numbers of patterns and the results are compared. It is shown that the analyses results with four row patterns and twelve row patterns are same. So, it is considered that the analysis can be carried out for only four rows of pattern for the design of incremental roll forming process.

• Applied Science and Convergence Technology
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• v.23 no.1
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• pp.54-59
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• 2014

The roll-to-roll (R2R) fabrication method to make micro-scale pillar arrays for biomimetic functionalization of surfaces is presented. Inspired by the micro-structure of plants in nature, a surface with a synthetic micro-scale pillar array is fabricated via maskless photolithography. After the surface is SAM (self-assembled monolayer) coated with trichlorosilane in a vacuum desiccator, it displays a hydrophobic property even in R2R replicas of original substrate, whose properties are further characterized using various pitches and diameters. In order to perform a comparison between the original micro-pattern and its replicas, surface morphology was analyzed using scanning electron microscopy and wetting characteristics were measured via a contact angle measurement tool with a $10{\mu}L$ water droplet. Efficient roll-to-roll imprinting for a biomimetic functionalized surface has the potential for use in many fields ranging from water repelling and self-cleaning to microfluidic chips.

• Journal of the Korean Society for Heat Treatment
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• v.31 no.2
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• pp.63-67
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• 2018

Recent mold industry uses many roll-to-roll processes that can produce high production speed and precision machining and automation process. In the circular cylinder mold, however, patterns of less than $10{\mu}m$ are difficult to manufacture and maintain. In this study, we fabricated a circular cylindrical mold with a DLC thin film which have high hardness, low coefficient of friction and high releasability by using lithography and lift-off process. The height, line width, and pitch of the fabricated DLC macro pattern are $3.1{\mu}m$, $9.1{\mu}m$ and $20.2{\mu}m$, respectively. The pattern size is finer than the current applied to the aluminum cylinder type, and this shows the possibility of practical use of DLC micro pattern roll mold.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.673-674
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• 2010

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.7-12
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• 2012

In order to cope with the requirements of smaller patterns, larger surfaces and lower costs in the fields of displays, optics and energy, greater attentions are now being paid to the development of micro-pattern machining technology. Compared with flat moulds, large drums with micro patterns (roll moulds) have the advantages of short delivery, ease of manufacturing larger surfaces, and continuous moulding. This paper introduced the machining process technology of the roll moulds for display industry. The environmental effects were discussed and the importance of temperature maintenance was experimentally emphasized. The real time monitoring system for micro machining was introduced. A commercial solution was used to simulate the micro grooving and a deformation model of micro machined pattern was finally introduced.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.461-466
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• 2007

There has been a great interest in printing technology as a low cost and mass production method for the application of printed electronics such as printed TFT, solar cell, RFID Tag, printed battery, and so on. In this study, apparatuses of gravure-offset printing are developed for fine line-width/gap printing and examining pattern distortion occurred in gravure-offset printing process. The fine line-width/gap pattern shows that it is possible to make around 20 micro-meter line-width/gap printing patterns. Pattern distortion is modeled, and the amount and shape of the distortion are calculated by using commercial FEM code. The roll-to-roll printing system under development consists of unwinder/rewinder, two printing units, one coating unit, drying units, guiding unit, vision system, and other auxiliary devices. For multi-layer printing, the system is designed to be capable of printing two different materials.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.4
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• pp.351-356
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• 2017

The resistance of printed patterns for electrodes fabricated using printing technology should be minimized. This parameter depends on the pattern width and thickness; however, from the viewpoint of printability, the printed patterns should be printed at the designed width. The resistance of the printed patterns as well as printability is affected by various printing conditions. In this paper, the printing condition is optimized to minimize the resistance of electrodes printed by the roll-to-roll gravure method. This is done by considering the spread ratio of pattern width as a parameter of printability using design experiments. The drying temperature, dryer fan speed, and printing speed are selected as effective factors for the experiment objective. The optimized conditions are obtained and reproducibility test using these demonstrates that the optimized conditions can produce low-resistance electrodes for printability of the pattern width.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.583-584
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• 2006

Printing technology has begun to get into the spotlight in many ways due to the low cost effectiveness to existent semi-conductor process. It also has very useful application areas, not only paper printing but also patterning for LCD color tilter, Photovoltaic patterning, RFID antenna, OLED, and so on. In this study, an apparatus of gravure offset printing was developed for fine line width printing. The pattern was composed of $20{\mu}m$ size of continuous lines of which pitch size was $40{\mu}m$. The printed pattern shows that it is possible to make around $20{\mu}m$ line-width printing pattern. The roll-to-roll printing system for fine line-width printing based on primary experiment is presented. For testing of multi-layer printing, the system was designed to be capable of printing two different materials from each printing unit using gravure-offset printing method and have a function of alignment of two printed materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.173-178
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• 2012

Currently, active research is being performed on printing of electronic devices such as RFID devices, flexible displays, solar cells, and e-paper. This technique has several advantages over existing technologies such as lithography and etching. In particular, RFID devices, flexible displays, solar cells, and e-paper require flexibility and a mass production system. Thus, attention is being focused on the roll-to-roll process. High quality should be guaranteed in the roll-to-roll printed electronics systems, and good thickness and roughness qualities must be ensured. Experimental design was applied to this problem to analyze the main effects and interaction effects of various factors. Matching technology between the nip roll characteristics and the quality of the print pattern in roll-to-roll printed electronics systems was proposed to improve the printing quality.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.455-456
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• 2012