• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.553-559
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• 2004

The servo motor is used for the driving power source of the conventional linear conveyor system. The mechanical power transfer system is needed for converting the circular to the linear operation. But this system causes some problems of position error, the necessity of the periodical maintenance. In this paper the study on application of transverse flux linear motor(TFLM) is carried out for the indexer system of LCD processing because TFLM has much thrust per a volume than the conventional motor. TFLM is suitable system for the indexer system because of capacity of acceleration, maximum speed and precision of the position, etc.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1885-1888
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• 2003

As high technology industries such as IT and display have developed, demand for application parts of micro lens and lens array has been extremely increasing. According to these trends, many researchers are studying on the fabrication technology for parts of the micro lens by a variety of methods such as MEMS, Lithography, LIGA and so on. In this paper, we have performed researches related to ultra precision micro lens, lens array mold and fabrication of Lenticular lens mold for three-dimensional display by using mechanical micro end-milling and fly-cutting fabrication method. Tools used in this research were a diamond tool of R 150$\mu\textrm{m}$. Cutting conditions set up feed rate, spindle revolution. depth of cut and dwell time as variables. And we analyzed surface quality variation of the processed products according to the cutting conditions, and then carried out experiments to search the optimum conditions. Through this research, we have confirmed that we can fabricate the ultra precision micro lens mold with surface roughness Ra=20nm and the holographic lens mold by using micro end-milling and fly-cutting fabrication method. Furthermore, we demonstrated problems happened in the fabrication of the micro lens and established the foundation of experimental study for formulating its improvement plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.3
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• pp.521-528
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• 2009

This study verify the conveying characteristic and adaptability of Straight Type Seeping Auger(STSA) which is built in Combined Grain Drying and Storage System(CGDSS). It is very important to design sweeping auger which makes Combined Grain Drying and Storage System having First-In-First-Out. In order to suggest desirable idea for sweeping auger of Combined Grain Drying and Storage System, an experiment that behavior of grain on the boundary surface which is made by rotation of STSA is executed and causalities to be given problem of STSA are pointed out.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1238-1244
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• 2011

This paper presents the matching method of reflectors for localization of laser navigation. The laser navigation is a device that measures distance and angle of reflector. The conventional major matching using the laser navigation is method that moves position of measured reflectors to position of installed reflectors and than rotate moved reflectors. However, it is difficult to use the industry because it has high computational complexity and high errors. To solve those problem, The proposed matching is method that create position of measured reflectors to assume that the position of installed reflectors is position of AGV and than rotate the position of installed reflectors. For experiment, we used AGV which was designed by ourselves, and compared positioning accuracy when AGV moves according to varying steering angle and driving speed.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.1
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• pp.75-81
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• 2011

Dissimilar joining of aluminum 6061-T6 alloy to aluminum 5083-O alloy was performed using friction-stir welding technique. The mechanical properties, hardness, macro- and micro-structure on dissimilar friction-stir-weld aluminium alloy were investigated. Mechanical properties of the weld mainly depend on which Al alloy is placed at the retreating sides of the rotating tool respectively during dissimilar friction-stir weld because the microstructure of stir zone was mainly composed of welded Al alloys of the retreating side. Onion ring pattern was observed like lamella structure stacked by each Al alloy in turn. It apparently results in defect-free weld zone that traverse speed was changed to 124 mm/min under conditions of tool rotation speed like 1250 rpm with 5 mm of tool's prove diameter, 4.5 mm of prove length, 20 mm of shoulder diameter, and $2^{\circ}$ of tilting angle. The 231 MPa of ultimate stress and the 121 MPa of yield point are obtained about the friction-stir-welded Al 6061-T6(AS) to Al 5083-O(RS).

• Composites Research
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• v.30 no.1
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• pp.35-40
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• 2017

In this study, natural fiber composites including flax fiber reinforcement was manufactured. It was tried to find optimum design of drill and machining factor for minimizing the damage during hole machining in natural fiber composites. Taguchi optimization was used for minimizing the number of experiments and evaluation of the effect of machining factor during hole machining in natural fiber composites. The experimental results indicate that the newly designed drill distributes cutting resistance well and minimizes surface roughness and produces fine surfaces. Developed new drill has been dispersed in the cutting resistance during processing, it was possible to obtain the smooth hole surface. Also, it was found that optimal rotational speed and feed rate of drill for hole machining.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.425-431
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• 2016

The usage of Friction Stir Welding(FSW) technology has been increasing in order to reduce the weight in automobile industries. Previous studies that investigated on the FSW have focused on the aluminum alloy. In this study, Al6061-T6 alloy plates having 5 mm of thickness were welded under nine different conditions from three tool rotation speeds: 900, 1000 and 1100 rpm, and three feed rates: 270, 300 and 330 mm/min. Specimen size of Micro Shear Punch(MSP) test was $10{\times}10{\times}0.5mm$. The mechanical properties were evaluated by MSP test and Analysis of Variance (ANOVA). The specimens were classified by advancing side(AS), retreating side(RS), and center(C) of width of tool shoulder. The optimal welding condition of FSW based on micro strengh was obtained when the tool rotation speed was 1100 rpm and the feed rate was 300 mm/min. The maximum load measured AS, RS, and C in the weldment was measured 554.7 N, 642.9 N, and 579.2 N, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.1
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• pp.41-51
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• 2016

Friction generated from balls and grooves incurs temperature rise in the ballscrew system. Thermal deformation due to the heat degrades positioning accuracy of the feed drive system. To compensate for the thermal error, accurate prediction of the temperature distribution is required first. In this paper, to predict the temperature distribution according to the rotational speed, solid and hollow cylinders are applied for analysis of the ballscrew shaft and nut, respectively. Boundary conditions such as the convective heat transfer coefficient, friction torque, and thermal contact conductance (TCC) between balls and grooves are formulated according to operating and fabrication conditions of the ballscrew. Explicit FDM (finite difference method) is studied for development of a temperature prediction simulator. Its effectiveness is verified through numerical analysis.

• Journal of the Korean Society of Propulsion Engineers
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• v.3 no.2
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• pp.25-36
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• 1999

The main objectives of this research are to experimently explain the drilling mechanism for the production of bad holes and good holes during the drilling operation, to investigate how a wide range of drilling parameter affect composite laminate strength reduction, and to find which type of test provides the greatest interrogation of notched composite laminates. To achieve these objectives, a bulk of test specimens have been drilled with 5 different drilling parameters and tested with compressive, tensile, and flexural loads. It was found that the drilling parameters had a measurable effect on specimen hole quality as measured by static strength. The specimens, which were well supported, which had the higher spindle speed and lower feed rate, and which were well clamped gave the best hole qualities. The flexural test results presented the most clear and consistent failure strengths relating to the drilling parameters and associated hole quality.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.4
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• pp.547-554
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• 2013

The fuel storage vessel installed in CNG vehicles can be largely divided into 3 parts: head, cylinder, and dome. Studies of the cylinder and dome parts have already been performed, but sufficient design data is not available about the head part. Therefore, expert field engineers heavily depend upon trial-and-error methods. Therefore, FE analysis is performed to review the hot spinning process for forming the head part of the CNG vessel using the Arbitrary Lagrangian-Eulerian (ALE) method. The effects of forming factors on the load were analyzed. The values of the factors were chosen to avoid defects in the head part and buckling, and the forming feasibility of the head part was investigated. Furthermore, a bursting test was performed to evaluate the safety of the storage vessel.