• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.245-248
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• 2008

This paper deals with the parameter study of roller leveling process of steel cord using finite element analysis. A simplified model of roller leveling process is constructed for the efficient numerical simulation considering the computing time. Using the constructed simulation scheme, the parameter study of main process parameters, such as back-tension and intermesh, is carried out in order to evaluate elastic recovery angle and roller force quantitatively. The effect of the initial shape of steel cord is also evaluated during the parameter study. And the mechanism of roller leveling process is verified by investigating the residual stress distribution.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.609-620
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• 2008

There may be several parallel equipments having the same function in a multi-stage manufacturing process, which affect the product quality differently and have significant differences in defect rate. The product quality may depend on what equipments it has been processed as well as what process variable values it has. Applying one model ignoring the presence of different equipments may distort the prediction of defect rate and the identification of important quality variables affecting the defect rate. We propose a procedure for data segmentation when constructing models for predicting the defect rate or for identifying major process variables influencing product quality. The proposed procedure is based on the principal component analysis and the analysis of variance, which demonstrates a better performance in predicting defect rate through a case study with a PDP manufacturing process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.323-327
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• 2009

Silicone is recently used for LED chip encapsulment due to its good thermal stability and optical transmittance. In order to predict residual stress which causes optical briefringence and mechanical warpage of silicone, finite element analysis was conducted for both curing and cooling process during silicone molding. For analysis of curing process, a cure kinetics model was derived based on the differential scanning calorimetry(DSC) test and applied to the material properties for finite element analysis. Finite element simulation result showed that the curing as well as the cooling process should be designed carefully so as to reduce the residual stress although the cooling process plays the bigger role than curing process in determining the final residual stress state.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.10a
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• pp.50-53
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• 2001

Hydroforming process has become an effective manufacturing process because it can be adaptable to forming of complex structural components. Tube hydroforming has been successfully developed in the real industrial field by many researchers. However, there still remains the constraint about shape which can be manufactured by tube hydroforming. In order to improve this constraint of shape and formability of conventional sheet metal forming, hydroforming process of sheet metal pairs becomes an important technology. In the present work, the finite element analysis of hydroforming process of sheet metal pairs is presented. After basic study about experimental parameters based on numerical analysis, hydroforming process of sheet metal pairs is developed which uses hydraulic pressure as a main forming source.

• Transactions of Materials Processing
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• v.3 no.1
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• pp.63-83
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• 1994

In this paper, the slab method have been applied to investigate the strip casting process in which hot coil is produced from molten steel directly. In the twin roll strip casting process, molten steel supplied by the nozzle cools and solidifies due to the heat extraction effect of the rolls and hot rolling of the solidified shell takes place simultaneously. The analysis of hot rolling has been carried out by using the existing results of solidification analysis for the twin roll strip casting process. The current slab method provides basic design data such as roll separation force, rolling torque, rolling power as well as end dam separation force which are required to design strip caster. The effect of friction on the basic process parameters are investigated also. It is shown that the use of appropriate friction coefficient is important and that the characteristics of hot rolling in the twin-roll strip casting process is quite different from the conventional hot rolling processes.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.592-597
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• 2001

An automobile lower arm has been fabricated in a prototype form by hydroforming with the aids of numerical analysis and experiments. For the numerical process design, a program called HydroFORM-3D developed here on the basis of a rigid-plastic model, has been applied to the lower arm hydroforming. The friction calculation between die and workpiece has been dealt carefully by introducing a new scheme in three-dimensional surface integration. To accomplish successful hydroforming process design, thorough investigation on proper combination of process parameters such as internal hydraulic pressure, axial feeding, and tool geometry has been performed. Results obtained from numerical simulation for a lower arm in hydroforming process are compared with a series of experiments. The comparison shows that the numerical analysis successfully provides the manufacturing information on the lower arm hydroforming, and it predicts the geometrical deformation and the thinning.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.271-274
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• 2002

The aim of FMEA method which is already generalized in the industry engineering is to grasp a possibility that defect forms will appear. And it is a means of prevention step to let person remove obstacles which have an influence on customers beforehand in order. The two parts of FMEA are Design FMEA which we prepare in an early stage and Process FMEA which we prepare in time previous to mass production. This Study apply Process FMEA to execution fields of the construction industry.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.494-496
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• 1996

The purpose of this study is to investigate the effect of process conditions on pore distribution in porous silicon layer prepared by electrochemical reaction. Porous silicon layers formed on p-type silicon wafer show the network structure of fine porse whose diameters are less than 100${\AA}$. In n-type porous silicon, selective growth was found on the pore surface by wet etching process after PR patterning. And numerical method showed high current density on the pore tip. With this result we confirmed that pore formation has two steps. First step is the initial attack on the surface and second step is the directional growth on the pore tip.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.108-117
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• 2015

In this paper, as a previous step of software development, through an analysis step in the basic design process of the FPSO crane, ERD, which could help develop common understanding between its developer and the user, was introduced. From the flowchart of the design process, the overall work flow in its development was understood. Then, after the design process of the crane was divided into many entities, the attributes of each entity were defined and the relationships between the entities were established, followed by ERD creation through the use of IDEF1X notation. The results of the analysis can be readily understood even by users who lack of software knowledge, and then their change requirements can be immediately reflected in the developed system that requires modification.

• Progress in Superconductivity and Cryogenics
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• v.4 no.1
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• pp.145-150
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• 2002

The distillation column is one of large energy consumable units in the cryogenic air separation process and the accurate energy analysis of this unit is necessary for choice of energy saving process. In this work, the energy method was adopted for energy analysis of a cryogenic nitrogen distillation column. In order to designing the energy saving distillation column, the exergy distribution of feed air, exergy efficiency and exergy loss for process condition was investigated and the optimal process condition to minimize the exergy loss was found. The result from this work can be used as a guideline for the choice of the process design conditions and efficiency improvement of cryogenic distillation column.