• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.369-375
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• 2002

The results of source location in terms of AE signal occurred by the spot exciting as suggested in this research, it has been confirmed that AE technique is quite fruitful in figuring out the location of the occurrence, form, size and direction of the defects. Thus, it is expected that the application of the experimental method suggested in this study would make it possible to identify, in the nondestructive way, the location of the defect in the material.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.55
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• pp.13-24
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• 2000

6 sigma movement is the most prominent quality improvement methodology in practice. Measurement plays an important role in helping any organization improve quality. Therefore, the measurement systems analysis is the first step for the quality improvement of manufacturing process in 6 sigma movement. In this study, we investigate the effect of Gage Repeatability and Reproducibility(Gage R&R) in view of defect rate and process capability indices, and provide guidelines for acceptance of gage repeatability and reproducibility(%R&R) for six sigma quality.

• Journal of the Semiconductor & Display Technology
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• v.13 no.3
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• pp.1-6
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• 2014

Visual defect inspection for electronics parts manufacturing processes is comprised of 2 steps - automatic visual inspection by machine and inspection by human inspectors. It is necessary that spatial points which were detected by the machine should be adequately clustered for subsequent human inspection. This research deals with the spatial clustering algorithm for the purpose of process productivity improvement. Distribution based clustering is newly developed and experimentally confirmed to show better clustering efficiency than existing algorithm - area based clustering.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.4
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• pp.1-6
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• 2005

In this study, on automatic ultrasonic testing system is used to detect defects of flawtest specimen. We study the effects of the difference of ultrasonic damped rate of the different materials on the judgment of defects. The results indicate that the difference of sensitivity compensating quantity is 2dB, and the judgment is correct over $90\%$ when a specimen is judged as a defect when it exceeds third grade.

• Journal of the Korean Data and Information Science Society
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• v.18 no.3
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• pp.773-782
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• 2007

The statistical process control charts are very extensively used for monitoring of process mean, deviation, defect rate or reject rate. In this paper we consider a control chart to monitor the process reject rate in the high yield process, which is based on the observed cumulative probability of the number of items inspected until r defective items are observed. We first propose selection of the optimal value of r in the CPC-r charts, and also consider the usefulness of the chart in high yield process such as semiconductor or TFT-LCD manufacturing process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.47-53
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• 2011

From recent research, it has revealed that Electroacitve polymer(EAP) has a physical limitation. Carbon nanotube(CNT) is known as the promising material which has excellent electro-mechanical characteristics and is mostly defect-free. It is expected that a successful synthesis of CNT and Nafion known as a primary material for IPMC would make a great improvement on its electro-mechanic feature. In this paper, we suggest the method of synthesis of CNT with Nafion which improves electro-mechanical characteristic. Using mechanical dispersion with Nafion and Isopropyl Alcohol(IPA), we disperse Single-walled carbon nanotubes(SWCNT). For a uniformly layer of CNT, we used a spray gun on a hot plate by a simplified method. In the result, we fabricated a disperse SWCNT/Nafion composite uniformly.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.6
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• pp.7-15
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• 2010

Recently, with the high performance and efficiency of machine, there have been required the multi-functions in various machine parts, such as the heat resistance, the abrasion resistance and the stress resistance as well as the strength. Fatigue crack growth tests were carried out to investigate the fatigue characteristics of high carbon steel (SM53C) experienced by high-frequency induction treatment. The Cam nose part of the Automobile's Cam shaft is strongly bumped with rocker arm or valve-lift. Therefore abnormal wear such as unfair wear and early wear occur in the surface. This abnormal wear causes a defect that bad timing open and close actions of the engine valve happen in the combustion chamber so the fuel gas will be combustion imperfect. Therefore, the cam shaft demands high hardness and wear resistance. In this study, high frequency heat treatment has been accomplished while wear test for material SM53C.

• Smart Structures and Systems
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• v.17 no.5
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• pp.795-817
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• 2016

A non-contact, in-situ and non-invasive technique for health monitoring of submerged fiber reinforced polymers (FRP) laminates has been developed using ultrasonic guided waves. A pair of mobile transducers at specific angles of incidence to the submerged FRP specimen was used to excite Lamb wave modes. Lamb wave modes were used for comprehensive inspection of various types of manufacturing defects like air gaps and missing epoxy, introduced during manufacturing of FRP using Vacuum Assisted Resin Infusion Molding (VARIM). Further service induced damages like notches and surface defects were also studied and evaluated using guided waves. Quantitative evaluation of transmitted ultrasonic signal in defect ridden FRPs $vis-{\grave{a}}-vis$ healthy signal has been used to relate the extent of damage in FRPs. The developed technique has the potential to develop into a quick, real time health monitoring tool for judging the service worthiness of FRPs.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.626-629
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• 2003

In order to achieve high-resolution and large-size displays, inspection technology is necessary and important. It is a powerful utility for process and yield improvement for the high valued panel realization. We indicated the challenge of advanced panel manufacturing on inspection ability and throughput. We also investigated the method to judge laser-crystallizing energy by inspection technology. Finally, the total defect number and critical killer defects were classified and discussed in this work.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.1
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• pp.59-65
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• 2004

Hollow flange-shaped parts rue widely used in transportation systems. For good quality products, in general, design of preforms and die shapes for a progressive forging process is an important issue. For the design of die shapes for the forging process of a hollow flange, computer simulations Were earned out using the rigid-plastic finite element method. Forging defects like folding were seen in the vicinity of die corners at the typical shape ratios of upper and lower dies Die shape ratios at which the forging defect could occur during the extrusion-forging process of the hollow flange were investigated. The results might be efficiently used for the proper design of perform shapes, die shapes, and forging processes.