• Proceedings of the KWS Conference
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• 1997.10a
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• pp.216-219
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• 1997

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.201-202
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• 1996

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.199-200
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• 1996

• Proceedings of the KWS Conference
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• 1990.11a
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• pp.14-16
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• 1990

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.3
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• pp.272-280
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• 2002

The recent research topics on $CO_2$ arc welding power supplies are focused mainly on the reduction of spatter generation. The method for reducing the spatters can be approached in several ways: finding the new materials fur consumable electrode and shielding gases, researching on the circuit topology and the controller. In this paper, the metal transfer and several control methods for the $CO_2$ GMAW were described. And it was proposed and compared with other schemes that the control method for reducing spatter by controlling the welding current when short-circuit and re-ignition.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.1
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• pp.109-115
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• 2004

The spatter and porosity could be occurred during$CO_2$CW laser welding of Primer- coated steel for shipbuilding. This study has suggested an alternative idea by examining of weld-defect formation mechanism. The primer-coated plate induced the spatter humping bead and porosity and these are main part of the welding defect. attributed to the powerful vaporizing pressure of primer attached on the base metal The zinc of Primer has a boiling point that is the lower temperature than melting point of steel zinc vapor will build up at the interface between the two sheets and this tends to deteriorate the quality of the weld by ejecting weld material from lap position or leaving porosity. Therefore introducing a small gap clearance in the lap position. the zinc vapor could escape through it and sound weld beads can be acquired. In conclusion, we suggested the occurred and prevented mechanism of weld defects with searching the factor.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.40-44
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• 1997

Along with the rapid growth in microelectronics and power electronics technologies, various advanced control methods have been successfully implemented in real time and shown to be useful in controlling CO2 arc welding systems with high dynamic performance. In this paper, the slope of welding currents is controlled not to be so high in the case of short circuit welding mode. This results in less spatter. In addition, the data-base is constructed for the optimal welding conditions.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.558-562
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• 1999

In this paper, the inverter spot welding system with high efficiency via an instantaneous power control is presented. In spot welding, instantaneous power control is utilized in order to attain less spatter and high welding performance. Also we proposed a PI controller for spot welder system using Evolution Strategy(ES) with varying search space. ES with varying search space which depends on fitness values at each generation is used to tune PI control parameters

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.5
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• pp.257-263
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• 1999

Recently the performance of CO2 arc welding machine has been advanced significantly through the adoption of inverter circuit topology which made it possible to control the waveform of welding current and thus to suppress the spatter generation. However, the optimum waveform is still uncertain. As a first step for figuring out the promising waveforms, this study was performed to set-up the experimental system for studying the effect of waveform variables, The system designed in this study is a digital controller using single chip microprocessor of 80C196KC. As a result of performance test of this system, it was demonstrated all of the waveform variables could be set individually and the resultant waveforms appeared to be pretty much the same as the intended one.

• Proceedings of the KWS Conference
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• 1997.05a
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• pp.145-147
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• 1997