• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.311-318
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• 2002

In this study, we developed an analysis method of plate forming by induction heating and verified the effectiveness of the present method through a series of experiments. The phenomena of the induction heating is a 3D transient problem coupled with electromagnetic, heat transfer, and elastoplastic large deformation analyses. To solve the problem, we suggest a proper model and an integrated system. Using the present analysis model, we can estimate the plate deformation in heating without experiments and simulate the plate bending process of induction heating.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.4
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• pp.417-425
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• 2008

In the line heating process, only angular distortion whose direction is perpendicular to that of a heating path is expected. However, it is observed that a deformation is induced in the direction of the heating line. Because of this, during forming a saddle type plate we experience unfavorable deformations in the unintended direction. In this paper we discuss the unwanted distortion in the manufacturing process by analyzing intermediate plates of saddle type during fabrication. For this analysis we consider the longitudinal and transversal directions separately and use the bending strain for the analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.9 s.252
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• pp.1148-1153
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• 2006

This paper deals with the effect of the direct heating method(DHM) for straightening the micro wire. Straightened micro wires have been widely used in the fields of the medicine and the semi-conductor. We have developed a micro wire straightening system by using the direct wire heating method. To controling the tension of the micro wire during the heating and straightening process, a precision tension sensor was set up. In order to avoid the surface oxidation during the heating process, the argon inert gas was supplied to the vicinity of the wire. And, this paper shows the correlation between the tension and the current when arson gas supplied to the tungsten wire. Through several experiments, the optimal tension and current were found. Also, higher straightness $({\approx}1{\mu}m/1000{\mu}m)$ and roundness$(<{\Phi}{\pm}2{\mu}m/100{\mu}m)$ founded when $500{\mu}600gf$ tension and 1.5 ampere.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.198-204
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• 1993

The study is concerned with finite element analysis and design of axisymmetric deep drawing by local heating. When the bottom shape of a cup is not flat but in complex-shaped, i.e., hemispherical, the cup cannot be drawn in one or two processes in the conventional deep drawing process and the limit drawing ratio is limited as well. By introducing local heating selectively with regards to the heating position, the formability of the sheet metal can be greatly increased with the reduced number of processes. In the Process analysisthe rigid- viscoplastic finite element method is employed and the temperature effect is incorporated. Bishop's step-wise decoupled method is employed to analyze the thermomechanical interaction between deformation and heat transfer. Axisymmetric deep drawing of a hemisphere-bottomed cup has been analyzed for various combinations of heat application in the punch and the die. At the first stage of deep drawing stretch forming is practically carried out by firmly pressing the blankholder with the punch and the die heated at various levels of temperature. Then at the second stage the same cup is drawn for the saame or different combination of temperature. From the computation, it has thus been shown that the fromability of a cup is greatly increased in two-stage deep drawing with increased limet drawing ratio.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.2
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• pp.93-100
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• 2021

Copper sheets has been used widely in electric and electron industry fields because they have good electric and heat conduction property of the material. And, in order to bond copper material, a kind of soldering process is generally used. But, because it is difficult to bond by soldering between overlapped thin copper sheets, so, another kind of brazing bonding process can be used in that case. But, because the brazing process needs wide bonding area, it needs heat treatment process in electric furnace. Generally, for spot welding of sheets, a conventional electric Resistance Spot Welding process(RSW) has been used, it has welding characteristics using contact resistance heating induced by electric current flow between sheets. But, because copper sheets has the low electric resistance, it is difficult to weld by electric resistance spot welding. So, in this study, an electric Resistance heated Surface Friction Spot Welding process(RSFSW) is suggested and is testified for the spot welding ability of thin copper sheets. It is known from the experimental results and simulation that the suggested spot welding process will be able to improve the spot welding ability of copper sheets by the combined three kinds of heating generated by surface friction by rotating pin, and conducted from heated steel electrode, and generated by contact resistance of electricity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.3
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• pp.218-222
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• 2004

We developed the stamper structured mold with moving core type with nano pattern. Among the factors affecting the quality of injection molding plastic parts, We studied the effects of moving core surface heating method on the transcription of injection molding plastic parts with nano structures. Moving core surface heating has been tested by three different methods. The first was conventional injection molding process without heating moving core surface, the second was halogen lamp radiation heating process and the last was MmSH process using gas flame. As a result of making injection molded parts by using thermoplastic amorphous resins such as COC, PMMA, MmSH method which is the most high temperature of moving core surface showed the best nano pattern transcription of the three methods, but the outcome of conventional injection molding process was not better than others.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.3
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• pp.84-89
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• 2003

The joint method and characteristics of lubricant Impregnated MC nylon and metal are analyzed. Considering the productivity and economics, two materials are Joined with the process of turning, knurling, and induction heating. The Joint strength is determined by adhesion of the melted nylon, the size of knurl, and the interference from the difference of the diameters. The parameters affecting induction heating process are analyzed. The adhesion strength of the melted nylon is measured. Finally the joint strength is analyzed in the environments of low, room, and high temperature. The nylon/metal Joined material is expected to be widely used as the sliding machine elements with good friction and shear strength.

• Transactions of Materials Processing
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• v.12 no.5
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• pp.457-464
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• 2003

In the powder compact melting technique, proper precursor fabrication is very important because density distribution after foaming and foamability are determined during precursor fabrication process. The fabrication of the precursor has to be performed very carefully because any residual porosity or other defects will lead to poor results in further processing. In order to evaluate the effect of the compaction parameters on the kinetics of the foaming process, a series of experiments were performed. In this study, aluminium foams with a closed cell structure were fabricated by using both the powder compact method and the induction heating process. A proper induction coil was designed to obtain a uniform temperature distribution over the entire cross sectional area of precursor. To establish the foamable precursor fabrication conditions, effects of process parameters such as the titanium hydride content (0.3∼1.5 wt.%), pressing pressure of the foamable precursor (50∼150kN) on the pore morphology were investigated.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.360-366
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• 2018

In shipyards hull forming is performed by the line heating method using a gas torch and by cold treatment using a roll-press. However, this forming process has some issues, such as difficulties in controlling and accurately estimating the amount of the heat input, as well as a harsh working environment due to exposure to loud noises and air pollution. The induction heating method, which is introduced in this paper, exhibits good control and allows for the estimation of precise heat input. Also, workers can carry out the induction heating in a comfortable working environment. In this research, the induction heating simulation, which consists of electro-magnetic, heat transfer and thermal elasto-plastic analysis, was developed and modified through induction heating experiments. Finally, the effective heating coil was designed for the automatic hull forming system based on the results of induction heating simulation. For the purposes of a future study, if an algorithm to obtain optimal working conditions is developed, automatic systems for hull forming can then be constructed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.35-40
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• 2016

In this study, the thermal and fluid dynamic characteristics for the coating process of large-sized water pipes was studied by heating the inside of a pipe directly with a gas burner. Heat and flow analyses were performed on large pipes with various inlet shapes. Using large pipes for coating was shown to be the proper shape for heating large pipes uniformly. This type has a screw with a diameter of 200 mm installed at the inlet to provide a rotational motion to the heating air. The rotational motion resulted in a uniform temperature distribution that ranged from $289.1^{\circ}C$ to $352.1^{\circ}C$ The optimized geometric configuration of the inlet of the pipe successfully and uniformly enhanced the thermal characteristics of the devised temperature limit.