• 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 KWS Conference
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• 2002.10a
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• pp.732-736
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• 2002

The introduction of newly developed intelligent and user-friendly robotics has opened a new era in shipbuilding. Together with traditional and low-cost mechanization a record level of welding automation rate has been achieved in the construction of cruise vessels. In the paper modem applications and recent developments of welding automation and robotics in shipbuilding have been described and some forecast for the future trends are given. Development in the field of shipyards will be continued with accelerated speed and we shall have interesting prospects for the near future. New laser techniques can boost the shipyards in a revolutional way when production is rapidly changing, materials will be lighter and quality demands are becoming more strict.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.430-432
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• 2002

Some confusion in the terminology concerning the weld quality and its assurance seems caused by the different practises currently in use around the world. Qualified welding personnel are not automatically certified personnel. Education and training are the tools to obtain qualification. Flexibility in training and education seems logical and the most cost-effective way to obtain qualified personnel. A third party seems essential for issuing recognised Certificates. Manufacturers of welded products continue to face increased demands and concerns regarding weld quality. The following are the main conditions influencing weld quality: $\bigcirc$ Establishing reliable productions procedures and tests that meet the requirements of established codes and standards. $\bigcirc$ Finding qualified welding personnel capable of reliably carrying out established welding procedures. The issue of hiring and keeping skilled welding personnel has been a crucial consideration for manufacturers worldwide for the past few decades. It will continue to be a concern for decades to come.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.678-682
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• 2000

The purpose of this study is to develop a powerful 6-axes general welding robot utilizing a low cost vision system. The developed vision system is composed of a CCD camera, a PC with windows 98 OS, and a PC-Robot communication program using Visual C++. A test was carried out to investigate whether the welding torch can precisely follow up the welding path. It shows that the result of this study can readily be applied to practical welding operations.

• Laser Solutions
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• v.11 no.3
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• pp.21-24
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• 2008

Hybrid laser welding technology is a good process to reduce a thermal distortion and increase the productivity. However, it requires a high investment and a massive modification of the fabrication line such as a gantry system, milling machine for the edge preparation, high power laser system and weld machine. Therefore the development of an economical laser welding system is a crucial point to apply this system in shipbuilding yard. In this study, a portable hybrid laser welding carriage was developed for I-butt joint without edge milling. It is expected that the carriage type system could reduce investment cost.

• Journal of the Korean Society for Precision Engineering
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• v.7 no.1
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• pp.63-73
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• 1990

Low cost automatic welding machine is developed for the purpose of welding process automation of automobile parts with two dimensional welding joints. Developed gantry type machine is equipped with X, Y and roll axis stepping motors, and dirive units units are designed by two phase on drive scheme using shift registers. Control system is constructed by single board microcomputer of Z80A CPU, and also it is equipped with parallel input output ports and counter-timer chips. Linear and circular interpolation of welding head movement is accomplished by employing software digital differential analyzers. It has been shown that contour error of develped system is withi ${\pm}1.0mm$, meaning that the machine is suitable for CO2 arc welding process of automoble parts and is expected it's application to industry.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.397-406
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• 2003

Resistance spot welding is widely employed in a manufacturing process. In recent years, the requirement for more sophisticated quality control procedures has been in mass production industries. The requirements for high productivity and better weld qualities have lead to the development of more widely available microcomputer-based control. In this study, the inverter type power source and welding servo gun are developed. As the results, we have some advantages over the previous methods such as pneumatic gun. One of them is that the precise pressure control can be attained during the welding process. In addition, production time and cost can be decreased.

• International Journal of Korean Welding Society
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• v.2 no.2
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• pp.57-60
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• 2002

Generally, the laser vision sensor makes it possible design a highly reliable and precise range sensor at a low cost. When the laser vision sensor is applied to lap joint welding, however. there are many limitations. Therefore, a specially-designed hardware system has to be used. However, if the multi-lines are used instead of a single line, multi-range data .:an be generated from one image. Even under a set condition of 30fps, the generated 2D range data increases depending on the number of lines used. In this study, a laser vision sensor with a multi-line pattern is developed with conventional CCD camera to carry out high speed seam tracking in lap joint welding.

• Journal of Welding and Joining
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• v.19 no.4
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• pp.379-383
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• 2001

Resistance spot welding has been widely used in the sheet metal joining processes because of low cost, high productivity and convenience. Recently, automobile and aerospace industries are trying to replace partly steel sheets with aluminum alloy sheets. But in the case of dissimilar materials, to apply resistance spot welding has been known to be very difficult owing to the effect of melting temperature. On this study, an effort was made to apply spot welding of dissimilar sheet metals, 2024 aluminum alloy and zinc coated steel sheet, evaluate the spot weld quality with tensile-shear strength test and nondestructive evaluation technique, C-scan image methodology. In this study results, as the current below 11 kA, melting of materials is not achieved well. Also as the current exceeds to 13.5 kA, the more spatters happen at welded zone and tensile-shear strength lowered. So, the feasibility of C-scan image technique proposed in the study is found to be suitable evaluation method for resistance spot weldability.

• Proceedings of the KWS Conference
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• 1995.04a
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• pp.118-122
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• 1995

The hydraulic or pneumatic valve spools become essential as the important components on the production of automatic hydraulic or pneumatic machinaries as mechanical industry is developed rapidly. The machining precision is asked for manufacturing the valve spools. They could be unstable in the quality by the conventional arc welding and they have a lot of technical problems in manufacturing because their shapes are generally small. By the Precision casting process such as lost wax process, the production cost will be increased. But by the friction welding technique, they will be able to be made without such problems. Furthermore, there is a few study on friction welding of such hydraulic valve spool steels and in-process real-time weld quality evaluation technique by acoustic emission. So that, the final purpose of this study is 1) the development of design and manufacturing technique of hydraulic or pneumatic valve spool by optimizing of friction welding, and 2) the development of in-process real-time weld quality evaluation technique by acoustic emission.