• Proceedings of the KWS Conference
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• 2000.10a
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• pp.34-36
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• 2000

It is difficult to realize automation of welding of lattice type in shipbuilding and assembly processing of shipbuilding and steel structures. Usually, the welding parts of lattice type are welded manually. So there are limitations in continuous and stable quality controls and in increase in productivity because the welding quality depends on worker's skill. That is, automation in welding is necessary. This paper shows shows the development results of a moblie robot for welding of lattice type. Specially. algorithms for its mobile speed and seam tracking controls are introduced.

• Journal of Welding and Joining
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• v.7 no.4
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• pp.12-21
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• 1989

Laser beam welding parameters have experimentally investigated, using a continuous wave 3kW $CO_2$ laser with the various travel speeds, beam mode and laser beam power in low carbon steels. An optimum position of focus and the effect of shielding gas on penetration depth with varying the flow range of 0.5 to 5.1m/min have been combined to investigate the effect of laser power and travel speed on penetration depth and bead width. It is found that the optimum position of focus in 3kW class laser is 0.5 to 1.5mm below the surface of the material. The flow rate of shielding gas affects the penetration depth and He is more effective than Ar. The penetration depth in laser welds of low carbon steels is between two and four times of the bead width. Laser beam welding of butt joints in 2mm thick carbon steel has been carried out to establish a weldability lobe. The lobe indicating acceptable welding conditions is introduced.

• Journal of Power System Engineering
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• v.18 no.3
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• pp.106-111
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• 2014

Welding is very popular method for joining two or more metals. However, welding causes residual stress and distortion and these give a bad influence to the structure strength. In this paper, TIG welding technique was performed to investigate the joint characteristics of AISI321 steel. For its evaluation, the orthogonal array method and variance analysis were applied with three factors of electric current, travel speed and argon gas and also three levels of each factor to tensile tests for optimum design. From the results, the increaser weld speed the narrower bead width and the lower weld penetration. The increaser electric current the brighter argon gas and the wider bead width. Also weld speed influenced most on the tensile strength and presumption range of tensile strength at optimal condition from reliability 95% was estimated to $635.02{\pm}14.64$. In addition the increaser weld speed and electric current the fracture occurred around bead vicinity.

• Laser Solutions
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• v.14 no.2
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• pp.1-7
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• 2011

The latest trends of vehicle technology development are fuel efficiency improvement, body designs declining air resistance and lightweight of materials. Especially, as lightened weight of materials makes engine efficient so that vehicles keep the best performance, it is the best way to protect the environment and reduce fuel consumption. In this study, we conducted laser welding by using 3-dimension remote scanner that is 5J32 aluminium alloy. Furthermore, conduction experiment that was 3 times repeated for changing factors such as observing angle, laser power and welding speed. we observed exterior and cross section of weled part and tensile strength. When increasing laser power and decreasing laser speed, tensile strength increased. In order to evaluate factors that affect tensile strength qualitatively we conducted ANOVA. We assumed that the factors are observing angle, laser power and welding speed. Then we found that laser power and laser speed affect tensile strength. We conducted evaluation of weldability of aluminium alloy by above ways.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.319-324
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• 2001

This paper presents the motion control of a mobile robot with arc sensor for lattice type welding. Its dynamic equation and motion control method for welding speed and seam tracking are described. The motion control is realized in the view of keeping constant welding speed and precise target line even though the robot is driven along a straight line or corner. The mobile robot is modeled based on Lagrange equation under nonholonomic constraints and the model is represented in state space form. The motion control of the mobile robot is separated into three driving motions of straight locomotion, turning locomotion and torch slider controls. For the torch slider control, the proportional integral derivative (PID) control method is used. For the straight locomotion, a concept of decoupling method between input and output is adopted and for the turning locomotion, the turning speed is controlled according to the angular velocity value at each point of the comer with range of $90^{\circ}$ constrained to the welding speed. The experiment has been done to verify the effectiveness of the proposed controllers. These results are shown to fit well by the simulation results.

• Bulletin of the Society of Naval Architects of Korea
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• v.6 no.1
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• pp.35-42
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• 1969

Penetrations of arc welding electrades are different by changing welding conditions, welding speed of travel and current, even though quite same ones. Changing status of penetration is studied by changing welding speed of travel keeping welding current constant, at first, and by changing welding current keeping welding speed of travel which was obtained prior experiment constant, afterward. The F-100 4mm $\phi$ rods, E4301 class, which covering substance is mainly ilmenite and a domestic representative product of this class electrode, are used for this experiment. The Marquette's No.130 5/32"(4mm)$\phi$ rods, E6011 class, and No. 140 5/32"(4mm)$\phi$, E6013 class, which were produced in the United Stated, are used to compare penetration with F-100 at same welding conditions. The covering substance of Marquette's No. 130 rods is mainly cellulose, and belong to deep penetration arc welding electrodes, the covering material of another rods is titania, and a kind f shallow penetration rods. The result of this study is as follow : penetration of F-100, domestic ilmentite covering electrade, E4301 class, is between E6011 and E6013 of the United States products. At the lower range of welding current, penetration is closer to E6013 than E6011, at the higher range, closer to E6011 than another; and the value of penetration ranges $1.65{\sim}2.70mm$ for 4mm$\phi$ rods in the adequate current range. The changing status of penetration is showed by following experimental formula. $P=KE_v^{-\frac{2}{5}}1^{\frac{3}{2}}$

• Journal of the Semiconductor & Display Technology
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• v.2 no.2
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• pp.21-24
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• 2003

Seam seal welding on the semiconductor package is a process for sealing the packages of semi-conductors, crystal parts, saw filters and oscillators with lid plate by seam welding. This paper presents the development process of automatic seam seal welding system. In this process, the process algorithm, high precision welding current control, design of welding head, high speed and high precision feeding mechanism and user interface process control program technologies are included.

• Journal of Welding and Joining
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• v.10 no.2
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• pp.19-31
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• 1992

A numerical study was performed to investigate the flow field and the heat transfer characteristics occurring in high power density welding which is important in many fields of engineering applications. A two dimensional quasi-steady state of keyhole welding model is simulated by using the finite volume methods. It is shown that the shape of isothermal line is elliptic and the temperature gradient is very steep compared with other welding method and the welding speed has on welding width and observed beam power.

• Journal of Welding and Joining
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• v.24 no.5
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• pp.62-66
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• 2006

Panel line is an important process occupying the largest work amount in shipbuilding. In this research product simulation has been carried out to establish the optimal production scheduling. For this purpose a web-based panel line simulator was developed using an object modeling technology and C# language. The balance of work-load and increase in the productivity by the improvement of production facilities and process are the key factors for a good scheduling. In this study SPRT(Shortest Remaining Process Time) rule was applied for the work-load balancing and a good result achieved. To increase the productivity in the stiffener welding stage which is a bottleneck; process, more welding heads and higher welding speed were tested using the developed simulator. The simulation results showed that either more welding head or higher welding speed decreased the total work time. Use of both, however, deteriorated the productivity because of the bottleneck in the following stage. This result points out that the improvement of production facilities and/or process should be evaluated with their influences on the leading and following processing stage.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.1
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• pp.68-74
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• 2016

The Nd:YAG laser welding process is one of the most advanced manufacturing technologies owing to its high speed and penetration, and has increased the automation and flexibility of an entire industry. Laser welding of dissimilar metals has been widely used to improve the wear resistance and corrosion resistance of industrial parts. The objective of this research is to investigate the influence of process parameters on the welding of SM45C and STS304 with CW Nd:YAG lasers. Bead-on-plate welding tests were carried out for several combinations of the experimental conditions. In order to quantitatively examine the characteristics of the dissimilar welding, the welding quality of the cut section, strain-stress behavior, and hardness of the welded part were investigated.