• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.229-232
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• 2003

In the roll forming process, a sheet or strip of metal is continuously and progressively formed into a desired cross-sectional profile by feeding it through a series of forming roll. Accordingly, it is important to maintain the material properties of the initial sheet and deform uniformly during the roll forming. The roll forming process was estimated in consideration of some factors such as material properties, strip thickness, roll diameter, roll velocity, and the deformation of the material that influence the forming length. The hydroforming technology has been recognized as a new technique in manufacturing industry, especially in automotive industry. The formed pipe in used in hydroforming process is manufactured by the roll forming. The formability during hydroforming is very sensitive to the state of pipes which are made by roll forming. Particularly the amount of hardening during roll forming affects the formability. Therefore, it is necessary to design the optimum roll flower to reduce the local hardening. In this paper, optimum roll flower which has uniform strain distribution through sheet width was obtained by comparing strain distribution in various roll flower. Finite element analysis(FEA) is performed to estimate the strain distribution related to hardening by roll forming. A numerical analysis is carried out by SHAPE-RF.

• 소성∙가공
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• 제5권3호
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• pp.232-238
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• 1996

A dynamic mill set-up technique was developed to achieva a more precise roll gap set-up of the finishing mill stands for steel strip rolling. In the conventional mill set-up model the set-up values such as roll gap and roll speed are determined before the sheet bar reached the entry side of the finishing mill train and maintained constant until the strip top end passes through the last stand. In the way however a dynamic set-up logic that gives a way to adjust the roll gap value of the final mill stand for the strip ingoing from the ahead of the front stand was developed and attached to the existing set-up model. The roll gap modification is based on the analysis of the observation in the third stand of the finishing mill train. The dynamic set-up model was proved very effective for the more precise mill set-up and for operational stability in the hot strip finishing mill train.

• 대한기계학회논문집A
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• 제26권2호
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• pp.329-339
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• 2002

In ship operation the consequency of roll motions can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization control system design have been performed and very good results have been achieved. In many studies, the stabilizing fins are used. Recently rudders, which have been extensively modified, have been used to exclusively to stabilize the roll. This paper examines the two-degree-of-freedom servosystem design technique to synthesize the yaw control system which achieves the course keeping object of the ship and the H$_{\infty}$ control approach to suppress the roll motion, respectively.

• 대한기계학회논문집A
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• 제30권10호
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• pp.1328-1334
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• 2006

In the rolling mills for sheet metal rolling, paper rolling and etc., the impurities of roller surface have crucial effects on the surface quality of the products obtained by rolling. The Roll Cleaner is a device to remove impurities on roller surface during a rolling operation. Nip Pressure means the line pressure interacted between the roll cleaner blade and the roller surface. The nip pressure is the most important parameter which decides the performance of roll cleaner, and it depends upon several factors including the cleaner design and its blade stiffness. This study, first, analyzes the mechanism of the nip pressure generation for a roll cleaner designed commercially, which is an crucial process for effective design of roll cleaners. Second, the technique for the measurement of nip pressure is developed, which is useful to verify the performance of roll cleaners and to setup them properly at factory floor.

• 지구물리
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• 제6권3호
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• pp.155-164
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• 2003

차원 전기비저항 탐사자료의 획득에 널리 사용되는 roll-along 기법의 타당성과 효율성을 현재 통용되고 있는 쌍극자-쌍극자 배열법(dipole-dipole array) 과 베너 슐럼버저 (Wenner-Schlumberger array)배열법 의 경우에 대하여 수치 모델링을 통해 분석하였다 천부 정보를 상대적으로 많이 포함하고 있는 가단면도 상부에 위치한 자료들은 기법에 의한 자료의 누락이 없으므로 천부의 전기비저항 이상대는 두 배열법에서 모두 성공적으로 영상화되었다 그러나 비교적 심부에 위치한 이상대는 roll-along기법으로 야기되는 자료의 누락으로 인해 왜곡된 형태로 나타날 수 있으며 이 현상은 자료획득의 수평 범위가 상대적으로 빈약한 베너 슐럼버저 배열법에서 더 크게 나타나는 것으로 확인되었다 또한 실제 탐사에서 쌍극자 쌍극자 배열법은 S/N비가 낮아 유한한 전극 개수로 구현할 수 있는 최대전극전개계수($n_max$) 까지 전극을 전개할 수 없는 경우가 많은 이유로 roll-along기법으로 인한 자료의 누락이 적게 나타나지만 베너 슐럼버저 배열법의 경우에는 S/N비가 높아 ($n_max$)까지 전극을 전개하게 되어 자 료의 누락이 커지므로 역산 단면의 왜곡이 야기될 수 있는 것으로 분석되었다 따라서 동일한 기본전극간격 ($a$)과($n$)을 사용하였을 때 쌍극자 쌍극자 배열법보다 깊은 median depth(Edwards, 1977)를 제공하는 베너 슐럼버저 배열 법의 경우 roll-along기법에 의한 자료의 왜곡을 줄이고 효율적인 현장 작업을 위하여 ($n_max$)보다는 자료의 누락이 무시될 수 있는 ($n_prob$)을 기준으로 가탐심도에 적합한 를 결정한 후 측선 중첩구간이 전체 측선 길이의 3/4이 되도록 전극을 전진 배치하는 전극배열 방식이 추천되며 이는 수치 모델링을 통해 확인되었다.

• International Journal of Precision Engineering and Manufacturing
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• 제4권1호
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• pp.56-62
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• 2003

The objective of this study is to adjust the roll gap for the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes for round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.1036-1041
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• 1997

The objective of this study is to adjust the roll gap for the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes for round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental form and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.

• 대한조선학회논문집
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• 제41권4호
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• pp.53-58
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• 2004

When a fast container ship or a naval vessel is turning, comparable roll motions occur. Therefore, roll effect has to be considered in the horizontal equations of motion of the ship to predict the maneuverability well. In this thesis, a new method to determine a roll model structure and estimate its coefficients by applying the system identification technique to the data of sea trial tests was proposed. The simulation results from the estimated roll model were well consistent with the true one in spite of the difference between the estimated and the true model structures of roll hydrodynamic moment.

• 마이크로전자및패키징학회지
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• 제22권4호
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• pp.25-29
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• 2015

저가격, 높은 생산성, 고해상도를 가지는 소자의 패턴 제작 방법에 대한 요구가 계속적으로 증가하고 있다. 롤투롤 연속생산 공정은 저비용, 대량생산이 가능한 차세대 공정으로 각광받고 있다. 본 논문에서는 PLC (planar lightwave circuit) 소자의 제작을 위해서 롤투롤 공정을 이용하여 제조하는 방법을 연구하였다. 제안한 기술은 polydimethylsiloxane (PDMS) 고분자를 이용하여 롤투롤 공정을 통해 PLC소자를 제작하는 공정을 연구하였다. 실리콘 웨이퍼에 형성된 마이크로 패턴을 복제 공정을 수행하였으며 이를 원통금형에 적용하여 롤투롤 공정의 롤 몰드(roll mold)로 사용하였다. 웹 텐션과 웹 속도의 공정 조건 최적화로 롤투롤 공정을 이용하여 PLC소자를 제작하였다. 제작된 PLC소자는 약4.0dB의 삽입손실을 가지는 $1{\times}2$ 광분배기이며, 제안한 롤투롤 공정 기술을 이용한 PLC소자의 제작 공정이 대량연속생산에 유효함을 확인하였다.

• 한국정밀공학회지
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• 제19권6호
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• pp.96-103
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• 2002

The objective of this study is to adjust the roll gap fur the dimension accuracy of bar in hot bar rolling process considering roll wear. In this study hot bar rolling processes fur round and oval passes have been investigated. In order to predict the roll wear, the wear model is reformulated as an incremental from and then wear depth of roll is calculated at each deformation step on contact area using the results of finite element analysis, such as relative sliding velocity and normal pressure at contact area. Archard's wear model was applied to predict the roll wear. To know the effects of thermal softening of DCI (Ductile Cast Iron) roll material according to operating conditions, high temperature micro hardness test is executed and a new wear model has been proposed by considering the thermal softening of DCI roll expressed in terms of the main tempering curve. The new technique developed in this study for adjusting roll gap can give more systematically and economically feasible means to improve the dimension accuracy of bar with full usefulness and generality.