• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.236-239
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• 1995

In this paper,Upper bound analysis to predict the formation of corner cavity during the final stage of backward extrusion is used. The critical condition for corner cavity formation is obtained by upper bound analysis. The quantitive relationships between corner cavity formation and process parameters are studied. To broaden forming limit area, driven container and multi-step forming process is proposed. As a result of FEM, forming limit is enlarged. And this results is compared with the analytric results

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.66-68
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• 2004

Induction heating is a process that is accompanied with magnetic and thermal situation. When the high-frequency current flows in the coil, induced eddy current generates heat to conductor. To simulate an induction heating process, the finite element analysis program was developed. A coupling method between the magnetic and thermal routines was developed. In the process of magnetic analysis and thermal analysis, magnetic material properties and thermal material properties depending on temperature are taken into consideration. In this paper, to predict the angular deformation, temperature difference and the shape of heat affected zone were discussed. Also appropriate coil shape for maximum angular deformation were proposed.

• Journal of Applied Reliability
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• v.15 no.3
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• pp.145-148
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• 2015

The products to meet the requirement of are installed in nuclear power plant and the reliability target should be provided in the requirement. However, it is not easy to set a reliability target using quantitative analysis. The objective of this paper is to propose a method of reliability target setting considered warranty cost for process controller and then compare a reliability target with reliability analysis result.

• Journal of Korean Institute of Industrial Engineers
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• v.33 no.1
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• pp.11-25
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• 2007

Despite surging interests in analyzing business processes, there are few scientific approaches to analysis and redesign of organizational structures which can greatly affect the performance of business processes. This paper presents a method for deriving and analyzing organizational relations from process models using social network analysis techniques. Process models contain information on who performs which processes and activities, along with the assignment of organizational units such as departments and roles to related activities. To derive social relations between organizational units from process models, three types of metrics are formally defined: transfer of work metrics, subcontracting metrics, and cooperation metrics. By applying these metrics, various relations among organizational units can be derived and analyzed. To verify the proposed method and metrics, they are applied to standard process models of the semiconductor and electronic, and automotive industry in Korea. This paper presents a taxonomy for diagnosing organization structure based on the presented approach. The paper also discusses how to combine analyses in the taxonomy for redesign of organizational structures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.905-909
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• 2002

Commutators of a starting motor for automobiles has been produced through various processes such as forging, segmenting, and assembling. And the conventional method producing an automotive motor commutator is not appropriate for saving material and cost, because it makes each segment separated one by one. Therefore a new process design is required in oder to avoid the assembling process. In this study, a new process design of the commutator of an automotive starting motor has been carried out to save material and manufacturing time by FE analysis. In the FE analysis, three forging processes are proposed for producing the copper(ASTM Cl1000) commutators of a starting motor. And forging experiments are performed to make an unsegmented commutator in order to verify the theoretically proposed process. And then, in order to get the final product, the forged commutator is passed through various postprocessing such as resin terming, and machining. From the experimental result, the forging process proposed from the FE analysis is verified to be an economical method for producing the commutator of an automotive starting motor.

• Journal of the Korean Society of Safety
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• v.33 no.2
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• pp.112-123
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• 2018

In this paper, we focused on the safety of workers in a remanufacturing process where a risk analysis is not carried out and suggested a criteria for evaluating injury risk. We analyzed a disassembly and a reassembly, which are important for the remanufacturing process. The disassembly includes the disassembly of product and the disassembly process of part and the reassembly includes only reassembly of part. First of all, we analyzed the remanufacturing process and a type of injury. Then, we reviewed the standards and determined the criteria for a severity and an occurrence. We set a bigger weight for the severity to allow the greater impact. And the injury risk score was defined as a sum of the weighted severity and the weighted occurrence. We conducted a qualitative analysis of the experience of field workers based on the criteria we set up. Questionnaires for the evaluation were formulated through interviews with experts.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.23-29
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• 2013

Recent advances in printing technology have increased the productivity of the roll-to-roll (R2R) printing process for printed circuitry. In the R2R printed electronics, characteristics of printed and coated layers are one of the most important issues that determine the functional quality of final products. The slot-die technology can coat a large area with high uniformity using low-viscosity materials; determining the process parameters is important to obtain excellent coating qualities. In this study, a viscocapillary model was used to predict qualities of coated layers and patterns. On the basis of analysis results, a novel meta model was derived using design of experiment methodology to improve accuracy. Sensitivity analysis was performed to define major parameters in R2R slot-die coating process. The coating speed was found to most significantly affect the coated layer thickness and was easily controlled. The performance of the proposed model is verified through experimental studies. Based on the statistical analysis results, R2R slot die process can be optimized to guarantee a desired thickness.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.105-113
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• 2019

A construction project is a complex process consisting of interdependent tasks. If one task has variation, other tasks will be affected additionally and it is difficult to reach consensus on task variation due to the characteristics of the construction site that is going on quickly and complicatedly. Therefore, this study identified the root cause of task variation in construction process. Adjacent matrix was created with the tasks corresponding to major causes of variation, and the network analysis was performed. The results of social network analysis in the construction process can stabilize the work flow in the complex process and improve the reliability of the process plan and the project performance.

• Design & Manufacturing
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• v.18 no.2
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• pp.29-34
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• 2024

This study intends to reduce forming load by adding die rotation to flange-upsetting process. Materials arc formed by the compression and rotational torque which are accrued from rotation of the lower die accompanied by axial compression of the punch. For the theoretic analysis of flange-upsetting process using rotation die, slab method was used. Furthermore, for the verification of the theoretic analysis results, FEM simulation using DEFORM 3D a commercial software was done, and through the model material experiment using Prasticine, the results were compared and reviewed. Flange-upsetting process using rotation die shows reduced forming load compared with process without die rotation and demonstrates uniform distribution of strain. And as for the effect of the reduction of forming load, the less the aspect ratio(h₀/d₀) and the greater friction coefficient, the greater effect is. With increase in die rotation velocity, the effect of forming load reduction also increases little by little, but its effect on forming load reduction is very negligible compared with other forming parameters. Theoretic analysis results and simulation results coincided pretty well. The flange-upsetting process using die rotation are evaluated as useful process that can produce reduction of forming load and uniform strain.

• Transactions of Materials Processing
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• v.13 no.5
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• pp.429-434
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• 2004

Manufacturing process for milli components has recently gained researcher's focus with the increasing tendency toward highly integrated and micro-scaled parts for electronic devices. The milli-components need more precise manufacturing process than the conventional manufacturing process since the parts require higher dimensional accuracy than the conventional ones. In order to enhance the forming accuracy and productivity, various forming procedures proposed and studied by many researchers. In this paper, forming analysis of milli-components has been studied with a new micro-former. In modeling of progressive dies, multi-stage forming sequence has been analyzed with finite element analysis by LS-DYNA3D. The analysis proposes the sequential die and part shapes with the corresponding punch force and dimensional accuracy. The analysis also considers the effect of elastic dies on the dimensional accuracy of the formed parts. The analysis result demonstrates that the elastic analysis in the milli-forming process is indispensable for accurate forming analysis. The analysis procedure in the paper will provide good information in design of a new micro-former and milli-component