• Journal of the KSME
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• v.49 no.8
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• pp.37-40
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• 2009

인쇄전자 소자를 생산하는 기법으로 R2R 방식의 연속 공정 기술이 부각되고 있다. R2R 공정에서 결과물에 중요한 영향을 미치는 요소들 중의 하나로 그라비어 인쇄 롤올 들 수 있다. 현재까지 그라비어 인쇄 롤 가공 기술은 획기적인 발전을 이루어 왔다. 이 글을 통하여 가공 기술과 인쇄 롤의 중요성에 대하여 소개하려 한다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.09a
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• pp.387-395
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• 1995

롤(Roll)의 주물 가공 시스템의 성능(Performance)분석의 문제는 일반적으로 관련된 많은 요인들 때문에 매우 복잡하다. 롤 제조 시스템의 성능과 관련된 주요 요인으로서 주형(Moulding) 제작, 원재료의 용해, 후처리 및 가공 공정 의 요인들을 들 수 있다. 본 연구에서는 이러한 복잡한 롤의 주물 및 가공공 정상의 요인들로부터 롤 제조 시스템의 불량률을 평가하기 위하여 발견적인 방법인 GMDH(Group Method Data Handling)-Type 모델링 방법을 이용하 였다. 롤 주물 가공 시스템의 성능을 불량률로 두고 이에 주요 영향 요인들 의 입력 Data를 위하여 현장 자료로부터 상하한 값을 구하여, Hyper-Cube 프로그램을 이용하여 필요한 수의 Data를 보완하여 사용하였다. 시스템 성능 과 관련된 인자들을 2개식 가능한 조합을 하고 이들 각각의 조합들에 대하 여 6개항으로 된 예측식으로 회귀분석하고 일정 수준 이상의 결과들만을 다 음 단계의 자료로 사용하였다. GMDH 방법은 매 단계마다 영향이 적은 변 수조합을 제외시키므로 최종 해는 그 정확성이 매우 높다. 본 연구를 위하여 GMDH 알고리즘에 따라 계산할수 있는 전산 프로그램을 개발하여 사용하였 으며, 적용예를 롤 주물제조공정에 응용하여 보였다.. 분석된 자료에 의하면 예측 오차가 매우 적음을 보였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1155-1165
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• 1990

A new method of predicting effect of rolling parameters on roll pressure, roll force, and power and energy consumptions in hot strip rolling is presented. The method is based on approximate solutions for velocity, strain rate, and stress distributions in the roll gap. The degree of approximation was examined by the finite element solutions. The theoretical predictions were compared with experimental data from hot rolling of steel strip and steel plate.

• The Korean Journal of Rheology
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• v.4 no.1
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• pp.35-45
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• 1992

어미현상의 예측을 위하여 사각단면이 링을 환상압연하는 공정을 3차원 강소성 유 한요소법으로 해석하였다. 환상압연공정의 점진적이고 변형영역이 두롤 사이 근처로 국한되 므로 계산시간을 줄이기 위하여 두롤사이를 통과하는 부분만을 해석하였다. 변형도율의 분 포, 압연력, 구동롤의 토오크, 링과 롤 사이의 접촉면에서의 압력분포 및 변형된 링의 단면 모양을 계산하였다. 압연력, 구동롤의 토오크, 특히 변형된 링의 단면모양, 즉 어미현상은 계 산결과와 실험이 잘 일치하였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.66.2-66.2
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• 2012

프린팅공정을 이용한 패터닝 기술은 디스플레이, 태양전지, RFID 등 다양한 분야에서 각광을 받고 있다. 프린팅공정은 대면적 패터닝 공정이 가능하며, 다단계 공정인 Litho보다 공정이 단순하다는 장점이 있지만, 현재까지 원하는 크기와 두께의 패턴구현이 쉽지 않다는 단점이 있다. 프린팅 공정을 전자소자의 패터닝 기술로 사용하기 위해서는, 다양한 선폭과 선 두께를 자유자재로 구현하는 것이 가능해야 한다. 또한 미세한 선폭을 인쇄할 수 있을 수록 더 미세한 전자소자 또는 디스플레이 소자를 만들어 낼 수 있으며, 박막을 구현하는 것은 유기소자를 인쇄방식으로 하기 위해서는 필수적이다. 본 논문은 이러한 정밀한 패터닝이 가능한 롤 인쇄 공정의 기본 메커니즘을 설명하고 이를 이용한 미세 박막 인쇄 공정을 실험을 통해 검증하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.829-837
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• 1992

This paper presents a new approach for the analysis of hot strip rolling processes. The approach is based on the finite element method and capable of predicting velocity field in the strip, temperature field in the strip, temperature field in the roll, and roll pressure. Basic finite element formulations for heat transfer analysis are described with emphasis on the treatment of numerical instability resulting from a standard Galerkin formulation. Comparison with the theoretical solutions found in the literature is made for the evaluation of the accuracy of the temperature solutions. An iterative scheme is developed for dealing with strong correlations between the metal flow characteristics and the thermal behavior of the roll-strip system. A series of process simulations are carried out to investigate the effect of various process parameters including interface friction, interface heat transfer coefficient, roll speed, reduction in thickness, and spray zone. The results are shown and discussed.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.31-38
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• 2008

This Study discussed the roll forming process analysis of levitation rail for urban Maglev vehicle. To verify validity of roll forming process, we analyzed roll forming process for track shoe which is similar to levitation rail. The analysis process was composed of 12 passes and was performed for only 8 passes except overlapping passes. In the variation of temperature with each pass, surface temperature of the structure was cooled from initial $1200^{\circ}C$ to $1010^{\circ}C$ during 30 second before first pass, and central temperature and surface temperature was cooled to $980^{\circ}C$ and $900^{\circ}C$ in final pass, respectively. A length of structure after final pass is about 5 times longer than that before roll forming process. A strain of structure had a higher value in the inner part of the track shoe and show from minimum 2.5 to maximum 6.5. A torque applying on roll appear high in 2, 3 and 4 passes and a maximum value was $27,000ton{\cdot}mm$. Also it was analyzed that a load to the normal direction needs maximum 300ton.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.3
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• pp.295-302
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• 2013

The two cross-roll straightening process at room temperature is a manufacturing method for improving the straightness of a drawn wire. The distribution and magnitude of the internal and surface residual stresses of the drawn wire are changed after the wire-drawing process through the two cross-rolls; this also results in a change in the diameter of the drawn wire. The remaining residual stresses of the drawn wire after the wire-drawing dimensional changes were analyzed according to the distance between the rolls, oblique angle between the axes of the roll and the wire, predicted residual stresses, and dimensional change in the final product. The oblique angle between the concave and convex rolls did not affect the residual stresses or dimensional change, but the distance between rolls did.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6977-6984
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• 2015

It is faced with the necessity of multi roll forming process of the ball slide rail which is made by adding the separate manufacturing processes, piercing, bending, trimming, to the roll forming process of a continuous plastic deformation, to improve the quality. However, the vibration and noise of the press machine in this process leads to the quality degradation of slide rail manufactured in this process. In this study, the roll was designed considering the optimal strain rates by the roll forming program with finite element method. And to estimate the static stability of the multi process the Von-Mises stress and deformation on the press was calculated with a structural analysis program. Also, to avoid driving systems in the resonance region their natural frequencies in the 1st and 2nd mode were calculated through the modal analysis. To verify its dynamic stability improvement the magnitudes of noise and vibration in the existing and studied system were compared using a microphone and accelerometers. And the widths and surface roughnesses of the rails which had been produced in the existing and studied process were measured. Therefore, it is known that multi roll forming process is stable in the analytical and experimental study.

• 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.