• Journal of Ocean Engineering and Technology
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• v.15 no.2
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• pp.79-87
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• 2001

In this paper, not only the development of optimizing of friction welding with more reliability and more applicability but also the development of in-process real-time weld quality (such as strength and toughness) evaluation technique by acoustic emission for friction welding of the engine exhaustive valve (SUH3-SUH35 dissimilar steels of 12.3mm, 16mm, 20mm, and 24mm in diameters) were performed, comparing with the other FRW matches of materials such as SUH3 to SUH31, STS303 and SUH3 to STS304. As an important result, the techniques for dissimilar friction welding optimization of engine heat resisting steels SUH3 and SUH35 (12.3mm, 16mm, 20mm, and 24mm) and its real-time weld quality evaluation by AE was developed, considering on both diameter and carbon equivalent effects.

• Journal of Ocean Engineering and Technology
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• v.10 no.2
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• pp.69-76
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• 1996

In-process quality control and high reliability of the weld are the major concerns in applying friction welding to the economical and qualified mass-production. Experimental examinations and quantitative analysis were performed for the optimiaztion of similar friction welding of hydraulic valve spool steels(SNCM220, SCM435, SACM645, SCM415, ${\varphi}24). The quantitative correlations were found between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation periods of the welding and the fatigue life as well as weld strength and welding conditions. A real-time evaluation system was developed for the friction weld quality by AE.

• Proceedings of the KIPE Conference
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• 2002.11a
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• pp.85-88
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• 2002

저항 스폿용접은 두 개의 금속판을 서로 겹쳐서 양쪽에 전극으로 압력을 가하면서 대전류를 흘려보낼 때 재료의 접촉면의 저항에 의해 발생하는 줄울열을 이용하여 재료를 용융시켜 두 모재를 접합시키는 방법이다 산업현장의 자동 용접라인에서 로봇암의 끝단에 부착하여 사용하던 기존의 공압건은 시편에 주어지는 압력이 일정하여 실시간 가압력 변화가 어렵고, 전극벌림의 임의 조정이 불가능하였다. 본 연구에서는 서보 모터를 채용한 서보건 시스템의 실시간 가압력제어와 용접도중 일정한 파우어를 공급하는 정전력 제어방식을 이용하여 용접 품질을 향상시키고자 한다.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.3
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• pp.145-153
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• 1994

In the fabrication of welded built-up beams, longitudinal deformation occurs due to welding, and this obstructs improvement of productivity and quality. In this study, to estimate the deformation due to welding, a simplified thermal elasto-plastic analysis method is proposed and verified by experiments. From the results of the simplified analysis, it is clarified that deformation coefficients defined in this study are the function of fabrication parameters. Based on this simplified analysis, a method to simulate the fabrication procedures for the built-up beams can be developed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.173-178
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• 2007

Improvement of welding property of seat fiame is necessary for safety because seat frame is a unique connecting structural part between the rider and vehicle. Generally the robot and jig system for own use is used for welding of seat frame and unwelded zone can be inspected because of the geometrical interference between robot and jig system. In this study the unwelded zone of the conventional welding jig system is analysed and the 3D modeling and design change to solve the problem is discussed. As a result the weldability of system is improved and the manual welding jig is unnecessary because of the optimal jig system.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.23-23
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• 2009

우수한 용접부 품질 때문에 TIG를 이용한 오비탈 용접은 파이프 용접에 널리 사용되고 있다. 하지만 루트갭이 없고 루트페이스가 큰 맞대기 오비탈 용접의 위보기 및 경사상진자세에서는 오목한 이면비드가 형성되기 쉽지만, 이러한 문제를 극복하기 위한 연구는 희박한 실정이다. 본 연구에서는 위보기 및 경사상진자세에서 볼록한 이면비드의 형성을 연구하기위해서 용융지의 제어 방법을 적극적으로 검토하였다. 4mm 두께의 SS400 시편을 위보기 및 경사상진자세에서 각각 Bead-on-plate 용접하고, 이 때 비드성형기의 사용에 따른 비드 형상 변화를 관찰하였다. 텅스텐 전극과 비드 성형기간의 거리(Tip To Former Distance, 이하 TTFD)를 4.5mm에서 7.5mm로 1mm단위로 변경시켜 실험하였으며, TTFD가 증가할수록 위보기 및 경사상진자세에서 이면비드 높이가 감소하였으며 표면비드의 처짐이 증가하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.8
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• pp.1374-1380
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• 2002

Recently, the use of Robot increase little by little for the purpose of developing a welding quality and productivity in the welding part. It is more important to contact the seam for arc welding before moving a welding robot. There are two types of method to contact the seam namely contact and non-contact type largely. In this paper, image processing sensor(a kind of non-contact sensor) is concerned to track the seam by using laser diode and CCD camera. A structured laser diode's light illuminated on the weld groove and the reflected shape is introduced by CCD camera. The image board captures this image and software analyzes this image. The robot is moved and welded exactly as acquired image X-Y data is changed with robot's X-Y value. Also, most of seam tracking are considered by changing the program simply in case of the different weld groove of plane surface.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.460-464
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• 2001

Recently, the use of Robot increase little by little for the purpose of developing a welding quality and productivity in the arc welding part. It is more important to contact the seam for arc welding before moving a welding robot. There are two types of method to contact the seam namely contact and noncontact type largely In this paper, image processing sensor(a kind of non-contact sensor) is concerned to track the seam by using laser diode and CCD camera. A structured laser diode's light illuminated on the weld groove and the reflected shape is introduced by CCD camera. The image board captures this image and software analyzes this image. The robot is moved and welded exactly as acquired image X-Y data is changed with robot's X-Y value. Also, most of seam tracking are considered by changing the program simply in case of the different weld prove of plane surface.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.3
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• pp.141-148
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• 2021

In this paper, we propose an algorithm of welding bead detection and evaluation using geodesic active contour algorithm and high pass filter with image processing technique. The algorithm uses histogram equalization and high pass filter as gaussian filter to improve contrast. The image processing techniques smoothens the welding beads reduce the noise on an image. Then, the algorithm detects the welding bead area by applying the geodesic active contour algorithm and morphological ooperation. It also applies the balloon force that either inflates in, or deflates out the evolving contour for a better segmentation. After that, we propose a method for determining the quality of welding bead using effective length and width of the detected bead. In the experiments, our algorithm achieved the highest recall, precision, F-measure and IOU as 0.9894, 0.9668, 0.9780, and 0.8957 respectively. We compared the proposed algorithm with the conventional algorithms to evaluate the performance of the proposed algorithm. The proposed algorithm achieved better performance compared to the conventional ones with a maximum computational time of 0.6 seconds for segmenting and evaluating one welding bead.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.3
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• pp.288-298
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• 2002