• Journal of Welding and Joining
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• v.14 no.5
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• pp.29-39
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• 1996

• 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.16 no.3
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• pp.102-110
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• 1998

The horizontal fillet welding is prevalently used in heavy and ship building industries to fabricate the large scale structures. A deep understanding of the horizontal fillet welding process is restricted, because the phenomena occurring in welding are very complex and highly non-linear characteristics. To achieve the satisfactory weld bead geometry in robot welding system, the seam tracking algorithm should be reliable. The number of seam tracker was developed for arc welding automation by now. Among these seam tracker, the arc sensor is prevalently used in industrial robot welding system because of its low cost and flexibility. However, the accuracy of arc sensor would be decreased due to the electrical noise and metal transfer. In this study, the signal processing algorithm based on the neural network was implemented to enhance the reliability of measured welding current signals. Moreover, the seam tracking algorithm in conjunction with the signal processing algorithm was implemented to trace the center of weld line. It was revealed that the neural network could be effectively used to predict the welding current signal at the end of weaving.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2701-2706
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• 2003

This paper describes weld seam tracking and error compensation methods of automatic plasma arc welding system designed for the corrugation panel that consists of a linear section and a curved section with various curvatures. Realizing automatic welding system, we are faced with two problems. One is a precise seam tracking and the other is an arc length control. Due to the complexity of the panel shape, it is difficult to find a seam and operate a torch manually in the welding process. So, laser vision sensor for seam tracking is equipped for sensing the seam position and controlling the height of a torch automatically. To attain more precise measurement of an arc length, we measure the 3D shape of the panel and analyze error factors according to the various panel states and caused errors are predicted through the welding process. Using that result, compensation algorithm is added to that of arc length control and real time error compensation is achieved. The result shows that these two methods work effectively.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.112-117
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• 2017

The arc, generated by Tungsten Inert Gas(TIG) welding, is stable and provides excellent quality of the weld. Since automation is difficult, a lot of work is performed by hand. In addition, to obtain the uniform weld quality is difficult when using a base metal having a nonuniform welding line, or when welding inside a pipe. Generally, TIG welding power has the characteristic of constant-current. The welding voltage is changed in proportion to the arc length. Hence, the automatic voltage control equipment should be applied at the TIG welding system. The automatic voltage control equipment has been designed using LabVIEW software. It consists of a manufactured voltage divider circuit, and jig for moving the torch. The voltage measurements and driving of the motor were performed through the algorithm implementation in LabVIEW. Welding was conducted while increasing the arc length. In this process, it was confirmed that the automatic voltage control equipment kept the arc length constant.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.3
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• pp.243-251
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• 2015

In order to develop an automatic system for welding thin steel plates with curvature such as the corrugated membranes of an LNG storage tank, a rotating mechanism should be firstly designed for the torch to easily follow the weld seam with a constant distance and angle. In this study, a torch rotating mechanism consisting of three circular links, two square-type links and a torch link was proposed for automation of the welding process. A weld-seam tracking system with two axis slides and the proposed rotating mechanism was successfully simulated with a dynamic simulation software. A prototype tracking system was manufactured and a tracking test with the system was then carried out. The test results with tracking system showed that the rotating mechanism could be implemented and it was feasible to be used in automatic tracking of weld seam with curvature.

• Journal of the Korea Safety Management & Science
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• v.12 no.2
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• pp.113-123
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• 2010

The goal of this study is to analyze an effect of productivity elevation. For the goal, the various methods of the productivity elevation were suggested and the system improvements were conducted. The S company was established in Ban-Wol Industrial Complex, Ansan-City, Kyonggi-Do on 2007. The company was hiring 22 employees. The main manufactures were heavy duty equipment parts and the amount of sale was two billion won on 2008. Problems which the company faced were ambiguous production target management and materials loss. To solve the problems, NCT work improvement and automatic welding were induced. There were steel saving of 3,780,000won/month and man-hour saving of 144,000won/month by redesign of the steel sheet for the NCT steel job. Also, changing from handwork to automatic welding, the man-hour saving for the welding job was 320M/H and saving of 4,225,600won/month. The others of systematic improvement for productivity elevation were usage of jig and daily equipment checklist.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.775-778
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• 1996

In this research, the robustness of a seam tracking for the automatic welding system is studied. The laser displacement sensor is used as a seam finder. X-Y moving table drived by ac servo motor controls the position and velocity of the torch-and-sensor part. However, dc servo motor is used to control the position and velocity of the torch. The sensor locates ahead of torch to preview the weld line, and brings about the inaccuracy on the torch tracking. To enhance the robustness on this system against the influence of disturbances and model uncertainty, H$\_$.inf./ control is applied to the angular motion of torch. The simulation shows that the tracking accuracy improved significantly. Also, experimental results give a good performance of H$\_$.inf./ control strategy to the automatic seam tracking system for the welding.

• Journal of Welding and Joining
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• v.14 no.4
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• pp.79-88
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• 1996

For improvement in productivity and weld quality, weld seam tracking and welding parameter control are very essential in the welding of a structure which can not be cxactly fit-up due to mismatch, discontinous gap, deflection, etc.. In this study, an automatic weld seam tracking system is developed for I-butt joint structure, and the system consists of XYZ working table, vision sensor and user interface program. In the developed vision sensor system, an image projection algorithm for weld-line detection and an adaptive current control algorithm for gap variation were implemented. The user interface program developed in this study by basing on the objct oriented concept could provide very convenient way to utilize the tracking system with the pull-down menu driven structure. The developed system showed a good seam tracking and weld quality control capability corresponding to deflected weld lines and gap variations.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.5
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• pp.42-52
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• 1997

Computer aided process planning and Offline programming are decisive factors in successful implementation of automated robotic production. However, conventional offline programming procedure has proven ineffective due to time-consuming teaching process for robot programming and due to inefficient system modeling. The paper presents an efficient procedure to semi-automatically generate robot job programs for ship block welding applications. In the research, the teaching positions are automatically determined by predefined rules which are functions of the type and the dimensions of the given welding section of ship block. And a sequence of robot movements and welding conditions such as welding type, welding current, welding speed, and welding torch orientation, are determined by use of Standard Program which is experimentally proved to work well for the welding wection group. Finally, a robot program for the welding section is generated automatically. Based on the algorithm, a offline automatic teaching software is developed. The paper presents also the algorithm and structure of the software.