• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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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.

• 한국기계가공학회지
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• 제3권1호
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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.

• 한국기계가공학회지
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• 제11권5호
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• pp.129-136
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• 2012

On this study, $CO_2$ gas, net of Ar gas, and mixed gas in solid wire(AWS ER 70S-6) and flux cored wire(AWS E71T-1) were used to weld on Mild steel(SS400). After the progress, the status changes of the welds in Mild steel(SS400) were investigated with compositional changes. For stable experiments, welding was conducted using the automatic feeder. Radiation testing, hardness testing, chemical composition analysis and penetrated cross-section were measured. Through these experiments, shapes of penetrated cross-section, chemical composition changes, and weld defects according to the variation of welding gas were known. Weld defects and weld cross-sectional shapes by the variation of the welding voltage were also detected.

• 한국기계가공학회지
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• 제15권5호
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• pp.31-38
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• 2016

This study proposes an optimal design for a robotic welding system for a high-strength steel armor plate. In order to identify the welding defect parameters, we analyzed the 4M (man, machine, materials, method) characteristics diagram, as well as a cause and effect matrix, to improve the productivity and quality of welding defects. From these analyses, we designed optimal welding conditions and carried out welding tests -- such as mechanical testing and macro structure tests - with positive results. We determined that it was possible to obtain a quality similar to manual welding with our robotic welding system. In the future, we expect that the system will be used as inspiration for future welding system designs.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.55-62
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• 2007

With the developments in knitting, manufacturing, and polymers, coated gloves have been evolved in a way to maximize occupational safety and functionality. In this paper, we have considered the PU-coating process for the glove knitted by Dyneema to reduce the occurrence of the defects due to air bubble. This paper classifies the types of defect due to air bubble and traces their forming mechanisms. The air between coating layer of glove and mold's surface forms the defects if it is not evacuated fully in the process of submerging into water. The defects can be suppressed or avoided by forming air-evacuating path on the surface of the molds.

• 산업경영시스템학회지
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• 제35권2호
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• pp.196-203
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• 2012

When manufacturing die casting mold, generally, the casting layout design should be considered based on the relation between injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects were differentiated according to the various relations of the above conditions. High-qualified products can be manufactured as those defects are controled by the proper modifications or the changes of die casting mold with the conditions. In this research, the proper manufacturing method was derived intensively for reducing the defect of the internal porosity of steering wheel housing which is very complicated to achieve a good mold design. The method was also derived for minimizing and for guaranteeing the product quality through the analysis of the casting problem and the deduction of alternative plans.

• 한국기계가공학회지
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• 제3권3호
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• pp.11-16
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• 2004

In this study, the characteristics of signals such as acoustic emission, vibration amplitude and noise level which are derived from the abnormal condition of compressor are investigated. The normal condition, vane stick sound and roller defect condition are chosen to analyze the signal in each cases. From the feature extraction of each signals, the dominant parameters of each signals which can identify the abnormal condition are suggested.

• 한국기계가공학회지
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• 제16권1호
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• pp.1-8
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• 2017

Warpage is a major defect frequently found in the injection molding process, and the reduction of warpage is a very challenging problem because of the uncontrollable factors, such as variations in the process parameters. Without any countermeasure against these noises, attempts to reduce the defects often lead to failure. In this research, a new robust design methodology, based on the Mahalanobis Taguchi System (MTS) to reduce warpage, is presented. The MTS performs the orthogonal array experiments and uses the signal-to-noise (SN) ratio of the Mahalanobis distance as a performance metric. The validity of the proposed method is illustrated through an optimal design of the injection molding process of a CPU base plate.

• 한국기계가공학회지
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• 제17권4호
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• pp.83-90
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• 2018

In this research, we developed a process design hot-forging technology that precisely forms an inner race. The inner race transmits power to a one-way clutch of an automatic transmission and minimizes the CNC machining allowance. For a multi-stage hollow shape (inner race), we proposed several shapes of blocker and finisher for the precision hot-forging process and analyzed the forging process using DEFORM. The hot-forging process was optimized for several parameters, such as metal flow pattern, forging defect, and forming load. Blockers and finisher dies in the hot-forging process were designed to select optimal shapes from finite element analysis, and experiments were conducted to optimize the hot-forging process.

• 한국생산제조학회지
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• 제4권4호
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• pp.42-49
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• 1995

It is not clearly known how defects or inclusions of a low carbon steel affect a fatigue strength. We study this issue using SM15C materials. The investigation is carried out by a quantitative evaluation, and experimental findings are: (1) a fatigue limit of A series smooth specimen is 205MPa, and that of B, C, D series is 245MPa, 304MPa and 245MPa, respectively. (2) the fatigue limit varies with respects to the stress distribution I the vicinity of a defects and crack. (3) the micro hole creates a half-circular shape crack, while the hole depth is not critical to the fatigue strength, (4) considering the fatigue strength, the hole diameter is more significant than the hole depth, and (5) Fatigue limit of artificially defected specimen is lower than that of a flawless one (5-10%), however, there exist allowance size and depth of defect which don't get to influence at fatigue limit.