• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.364-367
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• 2007

Typical seamless tube production methods are an extrusion and a rotary tube piercing. The rotary piercing process is more competitive than the extrusion process form view point of productivity, quality, and flexibility. It consists of twin rolling mills, a pair of disc or flat guides, and a plug. Twin rolling mills are skewed with proper angles in two directions. A round billet is progressively fed forward and rotated due to the rotation of twin rolling mills. Internal crack initiation and growth at central area of the billet are gradually progress because of the repeating actions of tension and rotation. Design variables in the rotary piercing rolling process are the feed angle, the cross angle, the reduction ratio, and the position of plug. In this work, a rotary tube piercing machine was developed and parametric studies on design variables were carried out using finite element analysis. The Brozzo ductile fracture criterion was utilized to determine an internal crack initiation.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.222-223
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• 2007

In 6.6kV Rotary Machine Stator Windings, Corona Discharge, Discharge at Conductor Surface, Slot Discharge and Endwinding Discharge is happended by electronic degradation. Also, if Partial Discharge cause in inner-part of Rotary Machine Stator Windings, it will be happended voltage and current pulse. In case of discharge spark, RF electromagnetic wave, which tranmits at discharge position, can happen. To detect this kind of RF electromagnetic wave efficiently, we have designed Planar Antenna Sensor with the CST MWS simulation program. Also we have confined the application possibility, which can analize the partial discharge in Rotary Machine Stator Windings. In the Future, sample of planar antenna sensor will be able to compare with the data of simulation by CST MWS program.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.51-54
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• 2012

This paper aims to design and analyze the stationary fixture type automatic rotary drilling machine and estimate the safety of the machine through simulations. Working conditions of typical rock excavating machines are mostly affected by geographical conditions on the sea, such as by the ebb and flow of the tide or high waves. Due to the size of machines, it is difficult to move and install machines. So it is necessary to develop a machine that not only can be moved and installed more easily also be operated more quickly and automatically. To validate the safety of the designed structure of the machine, static analysis has been carried out. The results of stress and deformation analysises show that the designed machine is stable and safe in hard working condition.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.2
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• pp.209-214
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• 2006

The eccentricity of the rotor causes a rotary machine to unbalance and the balancing to correct or compensate this is very important not only for dust-proof and anti -noise design but also for stabilization and durability of the rotary machine. In this paper, for developing the balancing machine to find and compensate such eccentricity, we will propose new way of measuring eccentricity using hall effect sensor that is different from the way in a conventional balancing machine. And we will show that it is possible to make balancing machine more compactly and cheaply by experiment results using hall effect sensor to measure eccentricity. Moreover we try to control and monitor the balancing machine by personal computer through serial communication.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.06a
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• pp.47-54
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• 1995

Rotary forging process has many advantages such as compacting of machine, low price of facilities and good quality of products. The last presented was a technical report about rotary forging press in the 100-ton class, which has the only orbital motion limited to the forming of axisymmetric parts. In this paper, the newly developed rotary forging press is introduced. The maximum capacity of forming load is 280 ton and five locking motion, this is, orbital, straight pivot, spiral and two kinds of clover can be available. This machine consists of transmission, double eccentric bush, rocking shaft, die set and hydraulic unit. Especially, the supports of rocking shaft and double eccentric bush are so crucial that hydrostatic bearings are adopted. Finally, it is expected that the technical know-how obtained in this research can be applied to the manufacturing of the another machine with large capacity.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.2
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• pp.195-202
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• 2015

Rotating equipment seldom fails without notice, so breakdowns can usually be predicted and avoided by watching for signs of failure. In this paper, We study case for rotary machine with a breakdown analysis. Also We analyze the solution of the safety and the future breakdown of the each rotary machine through vibration analysis using measurement data. The implementation of the measurement and the test results are discussed. The result with suggested method showed netter stable Condition Monitoring & Diagnostics.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.329-330
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• 2010

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.454-461
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• 1999

A concrete floor trowel machine, developed in the U.S in 1990's, consists of only two rotary trowels, and doesn't need any other mechanism for motion such as wheels. When the machine flattens a concrete floor with its rotary trowels, the machine can move in any direction by utilizing the unbalanced friction forces occurring between the rotary wheels and the floor when the trowels are tilted in appropriate directions. In order to automate the trowels machine, this paper proposed the self-propulsive concrete finishing trowel robot which has twin trowels. For the control of the robot, this paper discussed the following. Firstly, the dynamics model of the driving frictional force applied on each trowel from the floor is derived. Secondly, the relationship between the driving force for the robot and the control variable of the robot is derived. Finally, the basic motion of the robot are realized by using the obtained relationship. This paper figures out how the concrete floor finishing robot with tow trowels moves and will contribute to realizing it.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.438-443
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• 2005

Handy paint rollers with simple or no patterns are generally used to transcribe its design to a wall just after painting. However, the types of the patterns are limited to several conventional ones, so that interior planners' or decorators' demands are gradually tending to getting attractive roller designs. In order to obtain abundant kinds of the roller designs, a new advanced 3D machining method should be established for cylindrical models. In this paper, a post-processor that can generate suitable NC data is proposed for multi-axis NC machine tools with a rotary unit. The 3D machining system with the post-processor is also presented for an attractive interior decorating. The machining system allows us to easily transcribe the relief designs from on a flat model to on a cylindrical model. The effectiveness of the proposed 3D machining system using the post-processor is demonstrated through some machining experiments.

• Proceedings of the KIEE Conference
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• 2008.10a
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• pp.97-98
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• 2008

In 6.6kV Rotary Machine Stator Windings, Corona Discharge, Discharge at Conductor Surface, Slot Discharge and Endwinding Discharge is happended by electronic degradation. Also, if Partial Discharge cause in inner-part of Rotary Machine Stator Windings, it will be happended voltage and current pulse. In case of discharge spark, RF electromagnetic wave, which transmits at discharge position, can happen. To detect this kind of RF electromagnetic wave efficiently, we have designed Planar Antenna Sensor with the CST MWS simulation program. Also we have confined the application possibility, which can analyzes the partial discharge in Rotary Machine Stator Windings. In the Future, sample of planar antenna sensor will be able to compare with the data of simulation by CST MWS program.