• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.614-618
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• 2002

In hot strip mills, Portable Roll Scanner (the portable roll surface temperature and profile measuring device) can be used to calibrate on-line Process models for strip crown and flatness by measuring the thermal expansion and wear profile of the rolls. And the surface temperature measurement can be used to optimize the roll cooling system. Portable Roll Scanner consists of the measuring device, which has two contact inductive distance transducers for roll profile measurement and one infrared Pyrometer for surface temperature measurement, and computer-based controller that is equipped with the measuring device. By the wireless data communication, the data is transferred to the memory of notebook for further analysis. After roll extraction from mills, Portable Roll Scanner measure the roll profile and surface temperature simultaneously along the work roll face and display the results in the TFT color monitor of notebook. Portable Roll Scanner is useful at mill-side and roll grinding shop.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.308-312
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• 1999

Developed the model equations which calculate roll force, roll power during hot rolling in real time. The variables which mainly effect on the roll force, roll power are shape factor, reduction, roll diameter, roll velocity, strip inlet temperature, carbon content of strip and strip-roll contact friction coefficient. Among these variables roll diameter, roll velocity, inlet temperature, carbon content and friction coefficient can be excluded in interpolated model equation by introducing equation of die force(F'), power(p') of the frictionless uniform plane strain compression which can be calculated without iteration. At the case of coulomb friction coefficient of 0.3, we evaluated coefficient of polynomial equations of {{{{ { F} over {F' } }}}}, {{{{ { Pf} over {Pd }, { Pd} over {P' } }}}} from the result of finite element analysis using interpolation. It was found that the change of values of {{{{ { F} over {F' }, { P} over {P' } }}}} with the friction coefficient tend to straight line which slope depend only on shape factor. With these properties, developed model equations could be extended to other values of coulomb friction coefficient. To verify developed roll force, roll power model equation we compared the results from these model equation with the results from these model equation with the results from finite element analysis in factory process condition.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.81-89
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• 2009

Dancer systems are typical equipment for attenuation of tension disturbances. Lately, demands for high speed roll-to-roll machines are rising but it is prior to attenuate the tension variation on the web entering into the printing zone to achieve the speed increment. Maintaining a constant tension before the first printing cylinder is the key of high speed, high quality printing. Dancer has been researched in two ways, whether it is controlled or not. The first one is active dancer and the other one is passive dancer. In the active dancer, a position of idle roll of dancer is measured and the roll is moved by external hydraulic cylinder to control tension disturbances. While the passive one composed with spring, damper and idle roll has no external actuator to position the idle roll. The tension disturbance causes movement of dancer roll and the displacement of the roll regulates the tension variation. On the other hand a composite type of dancer is applied for roll-to-roll printing machines. It has same apparatus as passive dancer. The displacement of roll is measured and front(or rear) driven roller is controlled to position the roll. In this paper, it is presented an analysis of pendulum dancer including position feedback PI control and logic for PI gain tuning in roll-to-roll machines. Pole-zero map and root locus with varying system parameters gives a design method for control of the dancer.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.39-45
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• 2022

In this study, we investigated whether the interference occurring in forming roll surfaces could be eliminated by increasing the radius of the variable section forming rolls. The surfaces of the rolls capable of forming products with different flange heights and bend angles with the bend line tilted at an angle of 1° from the longitudinal axis were created using the general CAD software CATIA. Roll interferences were determined for the change in the forming roll radius. The minimum gaps between the upper and lower roll surfaces were measured for the change in the forming roll radius, and the roll interferences were calculated from the difference between the measured value and the thickness of the product. It was observed that the thickness of the product had a slight effect on the roll interference when the thickness was between 0.8 and 1.2 mm. It was also observed that the roll interference could be eliminated by increasing the roll radius.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.499-504
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• 1993

To find a way for establishing work roll initial crown according to roll conditions, computer simulation for predicting plate crown in plate mill is done and effects of roll conditions on plate crown is analysed. Roll gap profile and plate crown are measured to be compared to the calculated values. As a result,a regression equation to establish work roll initial crown according to roll cooditions such as backup roll diameter, backup roll crown and work roll crown is obtained.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.248-251
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• 2009

AB100 & CB100 are general products in the steel beam of the section shape. They are applied for construction, welding and shipbuilding structures. But currently roll damages are generated in the intermediate & finish mills during producing AB 100, CB100. The goal of this project is to conduct rolling & roll stress analysis using the 3D FEM program and to research the things which roll diameter affects roll stress. By the analysis results, it is determined that the recording roll stress where the roll diameter will be big comes to be small, and it is recognized that roll damage occurrences of finish rolling mills can be high by roll stress analysis results.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.2
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• pp.125-131
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• 2014

Winding is an integral operation in almost every roll-to-roll continuous process and center-winding is suitable and general scheme in the winding system. However, the internal stresses within center-wound rolls can cause damage such as buckling, spoking, cinching, etc. It is therefore necessary to analyze the relationship between taper tension in winding section and internal stress distribution within center-wound roll to prevent the winding failure. In this study, an optimal taper tension control method with parabolic taper tension profile for producing high quality wound roll was developed. The new logic was designed from analyzing the winding mechanism by using the stress model in center-wound rolls. The performance of the proposed taper tension profile was verified experimentally.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.748-753
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• 1996

The contact roll is often used to regulate the winding tension as well as the entrained air in a wound roli by adjusting the contact force to the winding roll. But the contact force generated by other rolls, like assistant nip rolls, in a winding(or roll changing) process may act as disturbance to the control of the winding tension. In this paper, the mechanism of a roll change process is analyzed. And, the behavior of the contact and the assistant nip rolls are mathematically modeled. A nonlinear PID(NPID) controller is designed to control the winding tension and to reject the effect of disturbance generated by the assistant nip roll on the winding tension variation. Computer simulation study showed that the performance of the suggested NPID controller is improved compared with that of the PID controller in con trolling the winding tension and in rejecting the effect of the disturbance.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.73-85
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• 1997

The rolling force and roll deformation behavior in the twin roll type strip continuous casting process has been computed to estimate the thermal charcteristics of a caster roll. To calculation of rolling force, the relationship between flow stress and strain for a roll material and casting alloy are assumed as a function of strain-rate and temperature because mechanical properties of a casting materials depends on tempera- ture. The three dimensional thermal dlastic-plastic analysis of a cooling roll has also been carried out to obtain a roll stress and plastic strain distributions with the commercial finite element analysis package of ANSYS. Temperature fields data of caster roll which are provided by authors were used to estimated of roll deformation. Roll life considering thermal cycle is calculated by using thermal elastic-plastic analysis results. Roll life is proposed as a terms of a roll revolution in the caster roll with and without fine failure model on the roll surface. To obtain of plastic strain distributions of caster roll, thermomechan- ical properties of roll sleeve with a copper alloy is obtained by uniaxial tensile test for variation of temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1742-1748
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• 2014

This study investigated the quality characteristics of commercial rice flour (CRF) and rice flours prepared by different milling methods for sulgidduk. For particle distribution, dried rice flour after the 1st roll mill using a pin mill showed a particle size of greater than $710{\mu}m$, whereas a particle size less than $250{\mu}m$ accounted for 48% of whole rice flour. This proportion was higher than CRF after the 2nd step roll mill. Crude protein, lipid, and ash contents were significantly highest in 1st roll mill samples. For color, roll & pin made up of many small particles showed a high L value. CRF and roll & pin showed significantly higher starch damage and water-holding capacity, whereas pasting temperature, peak viscosity, and setback of RVA pasting characteristics were lower than 1st roll mill. When rice cakes were made from three kinds of rice flour, roll & pin was not significantly different compared to the CRF. However, rice cakes made with 1st roll milled rice flour showed rough crumb and crust. Rice cake made with roll & pin or CRF showed similar characteristics for texture. In the quantitative descriptive analysis, rice cake made with roll & pin showed better appearance, flavor, taste, texture, and overall acceptability than CRF and 1st roll mill. Therefore, rice flour prepared by roll & pin could be applied to sulgidduk with high quality.