• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.225-232
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• 2004

Recently, there has been a rapid development in computer technology, which has in turn led to develop the automated welding system using Artificial Intelligence (AI). However, the automated welding system has not been achieved duo to difficulties of the control and sensor technologies. In this paper, the classification of the optimized bead geometry such as bead width, height penetration and bead area in the Gas Metal Arc (GMA) welding with fuzzy logic is presented. The fuzzy C-Means algorithm (FCM), which is best known an unsupervised fuzzy clustering algorithm is employed here to analysis the specimen of the bead geometry. Then the quality of the GMA welding can be classified by this fuzzy clustering technique and the choice for obtaining the optimal bead geometry can also be determined.

• Journal of Welding and Joining
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• v.32 no.6
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• pp.35-40
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• 2014

The contact tip for gas metal arc welding has important functions to transmit the welding current to the wire and to guide the wire to molten pool. If the contact tip is damaged, it is a cause of lowering the welding productivity due to removal of welding defects and replacement of contact tip. In case of the use of a contact tip for a long time the arc is unstable because the processed hole in the contact tip center is larger, and the variation of aiming position of the welding wire causes a seam tracking error. In this study, gas metal arc welding experiments using contact tip of three different materials were performed. The contact tips with Cu-P, Cu-Cr, and Cu-ODS were used at the experiments, and the welding characteristics by each contact tip were evaluated. After welding contact tip appearance, welding spatter adhesion amount of the nozzle, and weld bead appearance were evaluated. The welding current and welding voltage were measured to verify arc stability during arc welding.

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.68-70
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• 2002

A CCD camera with a laser strip was applied to realize the automation of welding process in GMAW. The Hough transformation was used to extract the laser stripe and to obtain specific weld points. In this study, a neural network based on the generalized delta rule algorithm was adapted for the process control of GMA, such as welding speed, arc voltage and wire feeding speed.

• International Journal of Korean Welding Society
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• v.3 no.1
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• pp.8-16
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• 2003

A major concern in Gas Metal Arc (GMA) welding process is the determination of welding process variables such as wire diameter, gas flow rate, welding speed, arc current and welding voltage and their effects on the desired weld bead dimensions and shape. To successfully accomplish this objective, 81 welded samples from mild steel AS 1204 flats adopting the bead-on-plate technique were employed in the experiment. The experimental results were used to develop a mathematical model to predict the magnitude of bead geometry as follows; weld bead width, weld bead height, weld bead penetration depth, weld penetration shape factor, weld reinforcement shape factor, weld bead total area, weld bead penetration area, weld bead reinforcement area, weld bead dilution, length of weld bead penetration boundary and length of weld bead reinforcement boundary, and to establish the relationships between weld process parameters and bead geomery. Multiple regression analysis was employed for investigating and modeling the GMA process and significance test techniques were applied for the interpretation of the experimental data.

• Journal of Welding and Joining
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• v.16 no.2
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• pp.93-99
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• 1998

The effects of welding conditions of gas metal arc welding on the elements loss of solid wire, oxygen content and impact toughness of weld metals were studied. Deoxidizing elements loss was increased with increase of arc voltage in both short-circuit transfer mode and globular transfer mode. It is believed that increase of arc voltage results in increase of reaction time between elements in the droplet and surrounding gas at the end of wire and in the arc column. Based on the thermodynamic equilibrium model, the oxygen content of weld metal can be predicted with the content of silicon and manganese as following : [%O] = $K([%Si][%Mn])^{-0.25}$, K = -15518/T+6.01. The equilibrium temperature was dependent on shielding gas, and it was 187$0^{\circ}C$ for $CO_2$ gas and 180$0^{\circ}C$ for 20%$CO_2$-80%Ar gas. The oxygen content of weld metal which shows maximum impact toughness was varied with deoxidizing alloy system of wires, 0.041 wt% for Si-Mn type wire and 0.026 wt% for Si-Mn-Ti type wire.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1997.04a
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• pp.36-41
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• 1997

With the trend towards welding automation and robozation, mathematical models for studying the influence of various parameters on the weld bead geometry in Gas Metal Arc(GMA) welding process are required. The results of bead on plate welds deposited using the GMA welding process has enabled mathematical relationships to be developed that model the weld bead geometry. Experimental results were compared to outputs obtained using existing formulae that correlate process input variables to output parameters and subsequent modelling was performed in order to better predict the output of the GMA welding process. The aim of this work was to explain the relationships between GMA welding variables and weld bead geometry and thus, be able to predict input weld bead size. The relationships can be usefully employed for open loop process control and also for adaptive control provided that dynamic sensing of process output is performed.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.6
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• pp.653-660
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• 2002

In this study, the toughness was evaluated by using the instrumented Charpy impact testing procedures for A15083-O aluminum alloy used in the LNG carrying and storing tank. The specimens were GMAW welded with four different mixing shield gas ratios (Ar100%+He0%, Ar67%+He33%, Ar50%+He50%, and Ar33%+He67%), and tested at four different temperatures(+25, -30, -85, and $-196^{\circ}C$) in order to investigate the influence of the mixing shield gas ratio and the low temperature. The specimens were divided into base metal, weld metal, fusion line, and HAZ specimen according to the worked notch position. From experiment, the maximum load increased a little up to -$85^{\circ}C$ , and the maximum load and maximum displacement were shown the highest and the lowest at -$196^{\circ}C$ than the other test temperatures. The absorption energy of weld metal notched specimens was not nearly depends on test temperature and mixing shield gas ratio because the casting structure was formed in weld metal zone. In the other hand, the other specimens were shown that the lower temperature, the higher absorption energy slightly up to $-85^{\circ}C$ but the energy was decreased so mush at $-196^{\circ}C$.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.148-152
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• 1996

A transient two-dimensional (2D) model was developed for investigating the heat and fluid flow in old pools and determining velocity profile and temperature distribution for the Gas Metal Arc (GMA) welding process. The mathematical formulation deals with the driving farces (electromagnetic, buoyancy, surface tension and plasma drag forces) as well as energy exchange between the molten filler metal droplet and weld pools. A general thermofluid-mechanics computer program, PHOENICS, was employed to numerically solve the governing equation with the associated source terms. The results of computation have shown that the electromagnetic and surface tension farces as will as the molten filler metal droplet have major influence in shaping the weld pool geometry.

• Journal of Welding and Joining
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• v.17 no.4
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• pp.39-45
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• 1999

The procedure of robotic Gas metal Arc (GMA) welding in order to achieve the optimized bead geometry needs the selection of suitable process parameters such as arc current, welding voltage, welding speed. It is required the relationships between process parameters and bead geometry. The objective of this paper is to develop the algorithm that enables the determination of process parameters from the optimized bead geometry for robotic GMA welding. It depends on the inversion of empirical equations derived from multiple regression analysis of the relationships between the process parameters and the bead dimensions using the least square method. The method not only directly determines those parameters which will give the desired set of bead geometry, but also avoids the need to iterate with a succession of guesses employed Finite Element Method(FEM). These results suggest that process parameter from experimental equation for robotic GMA welding may be employed to monitor and control the bead geometry in real time.

• 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.