• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.585-590
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• 1999

The conventional $CO_2$ inverter arc machine has constant voltage output characteristic and uses constant wire speed controller for welding current control. By adoption of PWM inverter to the welding machine, the spattering was reduced rather than the thyrister arc welding machine or AC arc welding machine. Moreover, by the high switching frequency, the output reactor size could be reduced evidently. Recently, the studies on optimal voltage and current waveform for the welding performance improvement have been studied. In this paper, a new instantaneous output current control scheme during the short circuit mode was proposed and showed the capability of arc stability improvement and the reduction of spatter generation.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.581-586
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• 2000

Gas metal arc welding(GMAW) uses a continuously fed electrode as a filler metal. The arc is shielded from atmospheric contamination by an inert gas active or inert/active gas mixture delivered through the welding gun and cable assembly. The recent research topics on $CO_2$ are welding machines are focused mainly on the reduction method of generated spatter by using new type consumable electrode metal or inverter control method. The various current waveform control methods have been researched for welding performance improvement. Until now current waveform control methods reduce to spatter occurred by instantaneous short circuiting,. but these methods is drawback that no reduce spatter occurred by arc reignition. In this paper the previous arc reignition current control method for welding performance improvement of inverter arc welding machine is studied and compared the various current control methods with the previous arc reignition current control method.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.170-173
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• 2002

The object of this study is to investigate the effect of compounded welding through the AE (Acoustic Emission) characteristics on static tensile test. This study was carried out a SM 490A, high tension steel using the low hydrogen type E4316 of electronic shield metal arc welding and compound wire of $CO_2$gas arc welding. $CO_2$welding, weak in the intensity of HAZ (Heat Affected Zone), can be improved by being combined with coated arc welding, Coated arc welding, weak in the intensity of the bead, can be improved by being combined with $CO_2$welding. Especially, electronic coated arc welding and $CO_2$welding complement the mechanical intensity of HAZ and the bead with each other. So, compounded welding increases the intensity in the special parts and enhances the quality of goods.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.34-39
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• 1997

With the development of semiconductor devices, adaptation of microcontroller prevails in industrial area. But in arc welding industry, there has not been much progress in adoption of microcontroller technology. There fore, this paper shows the application of digital control technology to welding machine. This paper presents the design of microcontroller that is appropriate for three phase $CO^2$ gas metal ar welding machine. By using microcontroller in $CO^2$ gas metal arc welding machine, the overall cost can be reduced compared to analog type one. Also TMS370C850 microprocessor is used as overall micrecontroller for the arc welding machine.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.166-170
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• 1998

The metal transfer of CO2 arc welding machine can be devided into short-circuit(low current) metal transfer. Especially in large crrent region, the main problem of CO2 arc welding machine is much spatter generation which is caused by mainly instant short-circuit matal transfer. So in this paper descrives new current control method in large current region, which can improve welding performance and lessen spatter generation. And as a result of experiment, the effect of proposed control method is demonstrated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.110-117
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• 2004

In automatic welding process using a robot, seam tracking is one of the important parts. Sensor for seam tracking is divided broadly into two categories as non contact sensor and contact sensor. The arc sensor is one of the non contact sensors, and it can be applied in weaving arc and rotating arc welding process. In such the arc sensors, rotating arc sensor can be applied to high speed welding over tens of Hz. The decrease of self regulation by high rotating speed causes to improve accuracy and response of sensor. In this study, fuzzy controller was used to track the seam for the $CO_2$ arc welding which had unstable arc. It could be shown that the rotating arc sensor was better than the weaving arc sensor.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.2
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• pp.92-98
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• 1998

With the development of semiconductor devices, adoption of microcontroller prevails in industrial area. But in are welding industry, there has not been much progress in adoption of microcontroller technology. Therefore, this paper shows the application of digital control technology to welding machine. This paper presents the design of microcontroller that is appropriate for three phase $CO_2$ gas metal are welding machine. By using microcontroller in $CO_2$ gas metal are welding machine, the overall cost can be reduced compared to analog comtroller. Also TMS370C850 microprocessor is used as overall microcontroller for the are welding machine.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.2
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• pp.128-137
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• 1999

Recently the pelionnance of CO2 arc welding machine has been advanced significantly through the adoption of i invelter circuit topology. which made it possible to improve welding perfonnances such as spatter generation and bead s state. But the conventional inverter arc welding machine generates constant output voltage which cause much spatter g generation dUling short-circuit and arc start time because it is unable to control output current instantaneously. So this p paper representes wavefCnm controlled inverter arc welding machine which control the wavefonn of welding current and t thus to suppress the spatter generation. And the system designed in this paper is the digital controller using single chip m microprocessor of 80C196KC. As a result of perfonnance test for this system, the spatter generation is reduced and s shOlt-circuit time period is stabilized compared to conventional one. And more by using switched mode rectifier for A AC/DC power convelter. unity power factor is maintained and low order halmonic spectrum is supressed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.4
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• pp.113-120
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• 2004

The object of this study is to investigate the effect of compounded welding through the AE(Acoustic Emission) characteristics for weld HAZ(Heat Affected Zone) under the static tensile test. This study was carried out an SWS 490A, high tension steel for electric shield metal arc welding(SMAW), $CO_2$ gas arc welding and TIG welding. Data displays are based on the measured parameters of the AE signals, along with environmental variables such as time and load. The accumulated AE event curve of HAZ definitely have the point of inflection subject to tensile test. The results of the tensile test of HAZ come out electric shield arc welding ＞$CO_2$ gas arc welding＞TIG welding in case of single welding, but generally the tensile test of HAZ come out electric shield arc welding＞ TIG welding ＞ $CO_2$ gas arc welding. These history plots give us useful and powerful information to analyze the results of material evaluation testing.

• 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.