• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.470-472
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• 1996

POSCO has a plan for facility expansion in plate mill by building No.3 Plate Mill. By No.3 Plate Mill's coming on line, POSCO' current plate production of 2.3 million tons will increase by over 1 million tons to 3.36 million tons (Currently, annual domestic demand for plates is 4.42 million tons). With the plan of facility expansion, POSCO also has the plan of integrating the Plate Warehouse. But, we came to have a question whether the roller table from the mill to the warehouse could carry extended products. Engineers working in the mill wanted to install transfer facility to reduce the load of the roller table, but the engineers in facility purchasing team didn't want to buy the new facility. So, We needed to analyzed the material flow by simulation. The simulation was done on the VAX system by SLAM II. And this project was done by two engineers for 2 months. In the end, we concluded that two transfer facilities are needed for material flow with no bottle neck point.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.220-223
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• 2000

In this study for the development of a 3D pattern mill, we designed its layout which has high stiffness and low-weight structure. We calculated the load of each axis component when 3D pattern mill is under the worst cutting conditions. On base of the calculations, we determined the size of its structure and selected main components of the machine. Also, using FEM we analyzed the layout design of 3D pattern mill to reduce the wcight of structure and increase stiffness of it. According to the load position and direction, shapes and values of the deformation and the stress distributions are calculated, also we calculated the natural frequencies and mode shapes in order ta modify and redesign the weak parts

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.08a
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• pp.142-149
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• 1999

Strip profile and shape control is one of the most important technologies in cold mill, especially for ultra-thin and wide cold strip. The 6-high mills, both of HCMW and UCMW mill, are known to be very effective for the shape controllability. The optimized values of these factors for set-up scheduling were analyzed and found that excellent strip control would be possible by controlling the combination of the influencing factors according to hot coil profile. The important considerations for operation were discussed for individual stand.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.349-358
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• 2004

The strip temperature history of finishing mill process is one of the most important factors to stabilize the facilities and to achieve the better product quality including a better prediction of roll force etc. The ultimate goal of this study is to improve scientific understanding of the finishing mill process in the view of heat transfer science. Finishing mill cooling facilities of KwangYang $\#3$ hot rolling are introduced and heat transfer analyses from FET to FDT are particularly focused in this study Three major tasks are successfully achieved as follows: 1) The temperature Prediction Models are developed. 2) The average absolute error is found to be less then 10 Celsius degree (about $8.5^{\circ}C$). 3) Prediction rate (less then $\bar{+}20$) are $10.2\%$ improved $(80.1\;\rightarrow\;90.3\%)$.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.991-997
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• 2013

In this paper, we propose a CFWC (CCD and fuzzy PID based width control) scheme to obtain the desired delivery width margin of a vertical rolling mill in hot strip process. A WMS(width measurement system) is composed of two line scan cameras, an edge detection algorithm, a glitch filter, and so on. A dynamic model of the mill is derived from a gauge meter equation in order to design the fuzzy PID controller. The controller is a self-learning structure to select the PID gains from the error and error rate of the width margin. The effectiveness of the proposed CFWC is verified from simulation results under a width disturbance of the entry in the mill. Using a field test, we show that the performance of the width control is improved by the proposed control scheme.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.7
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• pp.1597-1603
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• 1995

A prediction model on forward slip has been developed for presetting rolling speed of each finish mill stand in the continuous hot strip roduction. Those factors such as neutral point, friction coefficient, volume fractions undergoing width spread, shape of deformation zone at each side of entry and delivery of the rolls were taken into account. To reduce the speed unbalance between adjacent stands a refining method of adjusting friction coefficient has also been developed. On-line application of the model showed a good agreement in rolling speeds between the predictions and the actual measurements, and gave an outstanding improvement in the travelling stability of strip passing through the finishing mill train.

• Korean Journal of Materials Research
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• v.17 no.11
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• pp.606-611
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• 2007

This study was conducted to beneficiation of magnesite by dry grinding and air classification. The raw ore was ground in a ball mill and pin mill controlled with grinding time and linear velocity of grinding media and fractionated in an air classifier. Pin mill is more efficient than the ball mill for liberation. As a result, the MgO grade of concentrate was 47.1% with recovery of 51.51% for classified with 3,000rpm of air classifier for ground at 13,000rpm in pin mill.

• Electrical & Electronic Materials
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• v.10 no.9
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• pp.889-894
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• 1997

A miniaturized wind-mill type ultrasonic motor which has diameter in 12.7 mm and thickness in 2.0mm using PMN-PZT piezoelectric ceramics was fabricated. The wind-mill type ultrasonic motors has only three plate and of two wind-mill shape slotted metal endcaps a rotor whose end is hollowed out so that its periphery fits with the shape of the stator and a bearing to guide the rotor. A Finite Element Analysis was carried out to obtain the endcaps behavior under a radial displacement change of piezoelectric disk and to optimize the structure of the number of slots. Increasing the applied voltage the revolution speed of ultrasonic motors was increased. The maximum speed of 700 rpm and the maximum torque of 0.22 nN·m of the wind-mill type ultrasonic motors were obtained.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.176-181
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• 1994

As tools for machining precesion componants, end mills and ball end mill are widely used. For the end mill have longer cylindrical shape comparing diameter, they are liable to deflect when machining and induce geometrical error and deterioration of surface roughness. To improve the stiffness and the sharpness of the cutting edge of end mill, a software for manufaturing end mills are developed. The progeam predicts the result of helical flute grinding and the configuration of cutting edge which is located in cylindrical surface. Furthermore to facilitate the manufacturing end mill using CNC grinding machine, the setting conditions which satisfy the geometrical requirments like tool rake angle and stiffness are obtained.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.223-229
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• 2003

Tool wear monitoring is an important technique in the flexible manufacturing system. This paper studies the end mill wear detection using CCD camera and pattern recognition method. When the end mill working in the machining center, the bottom edge of the end mill geometry change, this information is used. The CCD camera grab the new and worn tool geometry and the area of the tool geometry was compared. In this result, when the values of the subtract worn tool from new tool end in 200 pixels, it decides the tool life. This paper proposed the new method of the end mill wear detection.