• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.596-599
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• 2004

The robotic $CO_2$ welding is a manufacturing process to produce high quality joints for metal and it could provide a capability of full automation to enhance productivity. Despite the widespread use in the various manufacturing industries, the full automation of the robotic $CO_2$ welding has not yet been achieved partly because the mathematical model for the process parameters of a given welding task is not fully understood and quantified. Several mathematical models to control welding quality, productivity, microstructure and weld properties in arc welding processes have been studied. However, it is not an easy task to apply them to the various practical situations because the relationship between the process parameters and the bead geometry is non-linear and also they are usually dependent on the specific experimental results. Practically, it is difficult, but important to know how to establish a mathematical model that can predict the result of the actual welding process and how to select the optimum welding condition under a certain constraint. In this research, an attempt has been made to develop an intelligent algorithm to predict the weld geometry (top-bead width, top-bead height, back-bead width and back-bead height) as a function of key process parameters in the robotic $CO_2$welding. To achieve this above objective, Taguchi method was employed using five different process parameters (tip gap, gas flow rate, welding speed, arc current, welding voltage) as a guide for optimization of process parameters.

• Journal of Welding and Joining
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• v.29 no.3
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• pp.58-63
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• 2011

Bead shape control with gas force process has been developed to overcome the concave back bead in pipe orbital welding. However, It is impossible to make a convex back bead using the existing gas nozzle, because it has high gas-consuming and low gas force. The purpose of this paper, to develop optimum shape of nozzle which to reduce the consumption of gas, maximizing the shield gas force with low cost and high productivity coincide the Green welding. In this paper venturi-type nozzle was compared with existing CP-type nozzle by TIG pulse welding in overhead position. As a result, CP-type occurs the wormholes in the overhead position, but the Venturi-type without the pore and formed a good bead appearance.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.102-109
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• 2005

An attachment part of the construction equipment frequently claimed from the crack occurrence that takes especially at the bucket. therefore we execute the fatigue examination and changes the welding method at the same materials. we executed a fatigue crack propagation experiment and got the conclusions at the normal temperature and Frequency 10Hz. We carried out butt welding for structure steel of SM490A and make three kinds of specimen of different weld method each. The fatigue limit of CASE 1 was determined to the low than CASE 2, CASE 3. the CASE 2 putting the interval of the 2mm creates back plate and make fatigue limit to high. Bead shapes and weld surfaces shape influence on fatigue life of materials. Specially, the crack growth becomes starting point that gap of back-plate and boundary surface of bead. It is confirmed by fracture showing on this study.

• Proceedings of the KWS Conference
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• 1998.10a
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• pp.160-163
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• 1998

• Proceedings of the KWS Conference
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• 1998.05a
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• pp.176-179
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• 1998

• Proceedings of the KWS Conference
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• 1997.10a
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• pp.210-215
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• 1997

• Proceedings of the KWS Conference
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• 1996.05a
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• pp.21-25
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• 1996

• Proceedings of the KWS Conference
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• 1999.05a
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• pp.203-206
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• 1999

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.349-353
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• 2012

As the world wind energy market grows rapidly, the productions of wind power generation equipment have recently increased, but manufacturers are not able meet this requirement. Particularly offshore wind energy industry is one of the most popular renewable energy sectors. To generalize welding processes, the welding automation is considered for steel structure manufacturing in offshore wind energy to get high quality and productivity. Welding technology in construction of the wind towers is depended on progress productivity. In addition, the life of wind tower structures should be considered by taking account of the natural weathering and the load it endures. The root passes are typically deposited using Gas Tungsten Arc Welding(GTAW) with a specialized backing gas shield. Not only the validation consists of welders experienced in determining the welding productivity of the baseline welding procedure, but also the standard testing required by the ASME section IX and API1104 codes, toughness testing was performed on the completed field welds. This paper presents the welding characteristics of the root-pass welding of high tensile steel in manufacturing of offshore wind tower. Based on the result from welding experiments, optimal welding conditions were selected after analyzing correlation between welding parameters(peak current, background current and wire feed rate) and back-bead geometry such as back-bead width(mm) and back-bead height performing root-pass welding experiment under various conditions. Furthermore, a response surface approach has been applied to provide an algorithm to predict an optimal welding quality.

• Design & Manufacturing
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• v.17 no.2
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• pp.47-54
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• 2023

The research direction of the automobile industry worldwide is speeding up research to improve fuel efficiency through weight reduction as the weight of automobiles increases due to environmental problems, convenience demands, and safety problems. As a way to solve weight reduction, there is a method of improving mechanical properties by improving the development and manufacturing method of lightweight materials with replaceable mechanical properties. Therefore, research on the molding and processing technology of aluminum, which is a lightweight material, is being actively conducted. In this study, aluminum material was applied. By using Autoform S/W, a press forming analysis program, the blank holding force, mold die R, and bead restraint force were selected in three levels, respectively, and the results and optimization of formability and shape freezing were carried out. In this study, aluminum material was applied. By using Autoform S/W, a press molding analysis program, the blank holding force, mold die R, and bead restraint force were selected in three levels, respectively, and the results and optimization of formability and shape freezing were carried out. The optimized results were confirmed by comparative analysis of formability and Spring Back. As a result of the experiment, it was possible to confirm the result value of the Spring Back of the final product according to the tensile change of the material.