• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.255-256
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• 2012

• 한국생산제조학회지
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• 제22권4호
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• pp.755-760
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• 2013

The dynamics of the winder roller of a roll-to-roll printing system for printed electronics is a time-varying system because of the variation of the winder roller radius owing to rewinding or unwinding of the web. Therefore, an adaptive control method considering the time-variant characteristics is required for precise tension control. In this study, the variable PID gain method is applied to the actual roll-to-roll system and verified by experiments for unwinder tension control. The required value of the winder roller radius for the application of the variable PID gain is estimated from the measurement of the winder tension and winder motor torque. The simulation results as well as experimental results show that the fixed PID gain control cannot stabilize the tension of the winder roller with varying winder roller radius. On the other hand, the variable PID gain method can control the tension of the winder roller regardless of the winder roller radius.

• 대한기계학회논문집A
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• 제34권3호
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• pp.263-271
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• 2010

e-Printing은 전통 인쇄 기술을 기반으로 하는 전자소자를 생산하기위한 새로운 기술이다. 이러한 인쇄 전자 소자들은 가격을 낮추기 위하여 대면적 인쇄가 요구된다. 이렇듯 원가를 절감하며 전자 소자에 요구되는 정밀도를 충족하기 위하여 롤투롤(Roll to Roll) 방식의 그라비아(Gravure) 인쇄 시스템이 하나의 대안으로 제시된다. 그라비아 인쇄에는 인쇄 전자 소자의 성능에 영향을 미치는 요소들이 매우 많다 : 건조 방식, 건조 온도, 운전 장력, 인쇄 속도, 잉크 점도, 잉크의 전도성, 망점 및 패턴의 정밀도. 이상에서 언급한 요소들은 각각 매우 밀접한 관계를 가지고 있다. 따라서 인쇄 전자소자의 성능을 향상시키기 위해서는 반듯이 인쇄 적합조건을 찾아야만 한다. 본 논문에서는, 전도성 잉크 및 그라이아 인쇄기를 사용하여 다양한 요소의 조건을 변화하여 패턴(선 및 면)을 인쇄하였으며, 각 인쇄 요소의 변화가 인쇄 전자소자의 성능에 미치는 영향에 관하여 분석 및 연구를 수행하였다.

• 한국생산제조학회지
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• 제19권6호
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• pp.867-874
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• 2010

RFID printing technology has emerged recently as an important tool for leading future IT. Therefore, many manufacturers concerning on low cost and mass production of the related products pay close attention to the printing technology. In order to realize printed electronics, the technologies for fine line-width/gap printing and registration are essential work. This study proposes a precise Roll to Roll control system that is capable of tilting two posts. Two controllable tilting posts can adjust film position at traverse direction for the precision registration. A mathematical model for representing the geometric features of each posts in Roll to Roll printing system is established first. Then an operating program is built to implement the system and to control film movement. For experimental test, a hard ware system is fabricated which is consisted of two AC servo motors, two posts tilting mechanisms, several guide rolls, and so on. The test results show the proposed system can control the film position precisely at transverse direction.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.353-354
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• 2009

• 대한기계학회논문집A
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• 제39권9호
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• pp.879-884
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• 2015

인쇄전자는 필름과 같이 유연한 웹 위에 기능성 잉크를 인쇄하여 전자소자 및 회로를 만들어내는 기술로써, 대면적 및 고속 대량 생산에 적합하며 유연소재의 전자소자를 만들어 낼 수 있는 차세대 공정기술이다. 이러한 롤투롤 인쇄전자 공정의 상용화를 위해서는 웹의 정밀 위치 측정이 요구되므로 본 연구의 선행연구를 통해 수 마이크로미터 측정 정밀도를 가진 광학 측정 시스템을 제안하였다. 하지만 선행연구의 횡 방향 측정은 웹 전체가 횡 방향으로 밀림 현상이 발생한 경우 이를 인지 할 수 없는 한계를 가지고 있다. 본 연구에서는 선행연구의 이송방향 웹 위치 측정 정밀도는 유지하며 웹의 횡 방향 위치에 따라 정렬패턴에서 반사되는 광량 차이를 이용한 웹의 횡 방향 위치 측정 시스템을 제안하였고 신뢰성을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.81-82
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• 2010

• 제어로봇시스템학회논문지
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• 제15권9호
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• pp.894-898
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• 2009

In a post printing section of roll to roll printing systems, scratch problem is the major defects. The functional qualities such as conductivity, mobility could deteriorate because of the scratch defect. In general, the scratch of the printed pattern on the flexible substrate was induced from a contact between rolls and printed pattern in the post printing section. In this paper, for non-contacting transfer of a moving web, a mathematical tension model has been developed considering strain due to air floatation and the proposed mode has been validated by numerical simulation. Additionally, the correlation between floatation height and speed compensation to control the tension and register are investigated. On the basis of the proposed model, a guide line of speed control in R2R printing system is presented to guarantee the non-contact between rolls and R2R printed pattern on the flexible substrate.

• 한국정밀공학회지
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• 제31권8호
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• pp.653-658
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• 2014

Roll-to-Roll printing process has become a great issue as a breakthrough for low cost and mass production of electronic devices such as organic thin film transistor, and etc. To print the electronic devices, multi-layer printing is essential, and high precision register control is required for this process. Unlike stop-and-repeat printing process, it is impossible to control the register in a static state since the roll-to-roll process is a continuous system. Therefore, the behavior of web such as polyethylene terephthalate (PET) and polyimide (PI) by the tensile and thermal stress generated in the roll-to-roll process as well as motor control of driven rolls has to be considered for a high precision register control. In this study, the correlation between curing temperature and thermal deformation of PET web is analyzed. Finally, it is verified experimentally that the temperature disturbance generates the more serious register error under the higher curing temperature.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1091-1097
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• 2008

Roll-to-roll based manufacturing plays an important role in producing devices at high speed with lower production cost in printed electronics and publishing industry. Web lateral control is one of the most important factors in improving the quality of product and contributes a considerable point in making devices at micrometer-level accuracy. In recent years, most algorithms proposed for web lateral control base on the Shelton‘s model for designing the feedback control system using the PI controller. Experimental results showed that the existing models do not fully describe the characteristics of the lateral dynamics for some typical operating conditions and so result in poor control algorithms. In this paper, a new lateral control algorithm is proposed for web lateral control system based on back-stepping approach. The outcome of this study proves the reliability throughout simulation results in Matlab/Simulink and comparison with the algorithms based on the existing results.