• Proceedings of the KWS Conference
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• 1999.10a
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• pp.47-50
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• 1999

The term adaptive control is often used to describe recent advances in welding process control but strictly this only applies to system which are able to cope with dynamic changes in system performance. In welding applications, the term adaptive control may not imply the conventional control theory definition but may be used in the more descriptive sense to explain the need for the process to adapt to the changing welding conditions. This paper proposed a methodology for obtaining a good bead appearance based on multi-torches welding system with the vision system in SAW. The methodologies for adaptive filling control used the welding current/voltage, arc voltage/welding current/wire feed speed combination and welding speed by using the vision sensor. It was shown that the algorithm for the welding current/voltage combination and welding speed revealed the sound weld bead appearance compared with that of the voltage/current combination.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.1-8
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• 2011

This paper describes a new method for a digital gas metal arc welding (GMAW) system. The GMAW system is an arc welding process that incorporates the GMAW power source (PS-GMAW) with a wire feed unit (WFU). The PS-GMAW requires an electric power of constant voltage. A constant magnitude is maintained for the arc current by controlling the wire-feed speed of the WFU. A mathematical model is derived, and a self-tuning fuzzy proportional-integral-derivative (PID) controller is designed and applied to control the welding current. The electrode wire feeding mechanism with this controller is driven by a DC motor, which can compensate for both the molten part of the electrode and undesirable fluctuations in the arc length during the welding process. By accurately maintaining the output welding current and welding voltage at constant values during the welding process, excellent welding results can be obtained. Simulation and experimental results are shown to prove the effectiveness of the proposed controller.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.90-99
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• 1999

Significant portion of the total manufacturing time for a pipe fabrication process is spent on the welding following primary machining and fit-up processes. To achieve a reliable weld bead appearance, automatic seam tracking and adaptive control to fill the groove are urgently needed. For the seam tracking in welding processes, the vision sensors have been successfully applied. However, the adaptive filling control of the multi-torches system for the appropriate welded area has not been implemented in the area of SAW(submerged arc welding) by now. The term adaptive control is often used to describe recent advances in welding process control by strictly this only applies to a system which is able to cope with dynamic changes in system performance. In welding applications, the term adaptive control may not imply the conventional control theory definition but may be used in the more descriptive sense to explain the need for the process to adapt to the changing welding conditions. This paper proposed various types of methodologies for obtaining a good bead appearance based on multi-torches welding system with the vision system in SAW. The methodologies for adaptive filling control used welding current/voltage, arc voltage/welding current/wire feed speed combination and welding speed by using vision sensor. It was shown that the algorithm for welding current/voltage combination and welding speed revealed sound weld bead appearance compared with that of voltage/current combination.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.253-255
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• 2006

Grey relational analysis has been carried out to develop a new approach for optimization of Nd:YAG laser and MIG hybrid welding parameters. The quality of welded material depends on welding parameters. The parameters chosen for current study include wire type, shielding gas, laser energy, laser focus, traveling speed, and wire feed rate. The welding experiments were performed on 6K21-T4 aluminum alloy sheet. Functional demands on products may vary widely depending on their use. The ultimate tensile stress, width, and penetration were chosen as the optimization criterion. Practice based on an orthogonal array which is following Taguchi's method has been progressed. Base on the results of grey relational analysis, the optimal process parameters were obtained. This integrated work was judged and it is observed that the results obtained by using the optimal parameters are much improved compared to those obtained through initial setting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.218-222
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• 2002

Micro-EDM is generally used far machining micro holes, pockets, and 3-D structures. For micro-EDM, first of all, micro-electrode fabrication is needed and WEDC system is proposed for tool electrode fabrication method. When tool electrode is fabricated using WEDG system, its characteristics are under the control of many EDM parameters. Also relations between the parameters affect electrode fabrication. In this study, experiments are carried out to analyze effects of EDM parameters about electrode surface integrity on micro-electrode fabrication. Experimental method and analysis are used to experimental design method. Factors used in experiments are composed of capacitance, resistance, pause time, wire feed rate, spindle rotating speed. As a result of experiments, capacitance and resistance affect electrode surface.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.1
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• pp.17-22
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• 2011

As the quality of a weld joint is strongly influenced by process parameters the welding process, an intelligent algorithms that can predict the bead geometry and shape to accomplish the desired mechanical properties of the weldment should be developed. In this study, prepared by ${\Phi}1.6mm$ GMA welding of metal wire nose Advice jowelui 350A 600A grade level inverter welder and DAIHEN SCR's were carried out using welding. Welding conditions were 5.5m/min wire feed rate the welding current is rapidly transmit approximately 260A, welding voltage was about 30V. CTWD a 22mm, shielding gas was Ar 20L/min and the welding speed was a 240mm/min. Using data collected during welding equipment welding current and welding voltage waveform was analyzed by measuring the volume of the transition mode. Addition of $CaCO_3$ as a loss of the spread of the weld bead dilution rate decreased, suggesting that, GMA in the overlay welding bead shape control, dilution control and may be used as a welding flux is considered. Stabilizing effect of the arc by the Ca-containing $CaF_2$, $CaCO_3$, $CaMg(CO_3)_2$, respectively, welding flux 0.1wt.% added GMA welding and weld overlay were evaluated with dilution, $CaF_2$, and $CaMg(CO_3)_2$ added to the dilution of Seemed to increase.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.6
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• pp.548-555
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• 2014

As a considerable, experimental approach, an Auto-carriage type of $CO_2$ welding machine and a MIG(Metal Inert Gas) welding robot under inert gas atmosphere were utilized in order to realize Al 5083 welding applied to hull and relevant components of green Al leisure ships. This study aims at investigating the effect of welding conditions(current, voltage, welding speed, etc) on thermal deformation that occurs as welding operation and tensile characteristics after welding, by using Al 5083, non-ferrous material, applied to manufacturing of co-environmental Al leisure ships. With respect to welding condition to minimize the thermal deformation, 150A and 16V at the wire-feed rate of 6mm/sec were acquired in the process of welding Al 5083 through an auto carriage type of $CO_2$ welding feeder. As to tensile characteristics of Al 5083 welding through a MIG welding robot, most of tensile specimens showed the fracture behavior on HAZ(Heat Affected Zone) located at the area joined with weld metal, except for some cases. Especially, for the case of the Al specimen with 5mm thickness, 284.62MPa of tensile strength and 11.41% of elongation were obtained as an actual allowable tensile stress-strain value. Mostly, after acquiring the optimum welding condition, the relevant welding data and technical requirements might be provided for actual welding operation site and welding procedure specification(WPS).

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1190-1199
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• 2014

As a considerable, experimental approach, an autocarriage type of $CO_2$ welding machine and a MIG(metal inert gas) welding robot in the inert gas atmosphere were utilized in order to realize Al 5083 welding to hull and relevant components of green leisure ships. This study aims at investigating the effect of welding conditions(current, voltage, welding speed, etc.) on thermal deformation that occurs as welding operation and tensile characteristics after welding, by using Al 5083, nonferrous material, applied to manufacturing of eco-environmental leisure ships. With respect to welding condition to minimize the thermal deformation, 150 A and 16 V at the wire-feed rate of 6 mm/sec were acquired in the process of welding Al 5083 through an auto carriage type of $CO_2$ welding feeder. As to tensile characteristics of Al 5083 welding through a MIG welding robot, most of tensile specimens showed the fracture behavior on HAZ(heat affected zone) located at the area joined with weld metal, except for some cases. Especially, for the case of the Al specimen with 5 mm thickness, 284.62 MPa of tensile strength and 11.41 % of elongation were obtained as an actual allowable tensile stress-strain value. Mostly, after acquiring the optimum welding condition, the relevant welding data and technical requirements might be provided for actual welding operation site and welding procedure specification (WPS).