• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 추계학술대회 논문집
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• pp.49-53
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• 2004

Thin spot welding is frequently used for industrial purpose, such as automobile and aerospace industries and household appliances due to its high performance. In these days, the systemization of welding process made it possible to produce more precise or smaller electric parts. And when it comes to welding of steel sheets, the size of nugget must be getting smaller. Therefore, welding conditions are limited to avoid defects, such as deformation, damage and weakening of joining area. In this research, thin spot welding establishes the welding conditions, and then the measurement of the nugget size by the nondestructive inspection has been conducted. As a result, the right estimation of the nugget size, the detection of corona bond near joining area, the selection of the optimum ultrasonic mode, and setup for ultrasonic inspection are studied. From the trustworthy solutions of the nugget size estimated by results of measurement, the optimum inspection conditions depending upon the width of welding parts are determined as well.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.301-306
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• 2003

Spot welding is frequently used for industrial purpose, such as automobile and aerospace industries and household appliances due to its high performance. In these day, robotization and systemization of welding process made it possible to produce more precise or smaller electric parts. And when it comes to welding of steel sheet, the size of nugget must be getting smaller. Therefore, welding conditions are limited to avoid defects, such as deformation, damage, weakening of joining area. In this research, the measurement of the nugget size by the nondestructive inspection has been conducted. As a result, the right estimation of the nugget size and void defects, the detection of corona bond near joining area, the selection of the optimum ultrasonic mode, and set up for ultrasonic inspection are studied. From the trustworthy solutions of nugget size estimated by results of measurement, the optimum inspection conditions depending upon the width of welding parts are determined as well.

• Journal of Welding and Joining
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• 제16권6호
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• pp.97-103
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• 1998

The bracket tilt among automobile parts is weld parts which construct the column assembly bracket tilt of equipments and accurate dimension after welding is more essential than weldment strength. By the way, it is insufficient that systematic study about this parts which have an importance on welding deformation. The reason is that welding deformation is complex problem with shape, size, material of parts and welding sequence, conditions etc. For reduction and removal of welding deformation, therefore, it is necessary that the security of welding deformation data and systematic examination about equipment, costs, work environment, manufacturing process etc. It is all the better that the prediction of welding deformation using simulation of welding process by FEA is supplemented. In this study, the countermeasure for this welding deformation of bracket tilt is brought up through experimental inspection before the choice of the optimum welding conditions with minimum welding deformation by simulation of welding process.

• 한국자동차공학회논문집
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• 제16권5호
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• pp.8-14
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• 2008

For nondestructive inspection of electron beam (EB) welding part in automotive power transmission assembly, a pulse-echo ultrasonic testing apparatus in water immersion has been applied using the ultrasonic waves with a frequency of 10MHz. However various problems have appeared during the ultrasonic inspection, which led to some significant mistakes in automatic quality evaluation of the welding parts. Experimental study showed that the state of water couplant medium containing some amount of contaminants, rusts and anti-corrosion agents had considerable influences on the reduction of ultrasonic amplitudes during wave propagation. The amplitude reduction depending on the coupling medium state could bring about some mis-diagnoses for defects in the welding parts. The results proposed that for a reliable inspection of defects in welds the state of water medium should be kept in about 15 volume fractions (vol.%) of anti-corrosion agents and in minimized contaminants.

• 센서학회지
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• 제33권3호
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• pp.179-184
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• 2024

In the car industry, welding is a fundamental linking technique used for joining components, such as steel, molds, and automobile parts. However, accurate inspection is required to test the reliability of the welding components. In this study, we investigate the detection of weld beads using 2D image processing in an automatic recognition system. The sample image is obtained using a 2D vision camera embedded in a lighting system, from where a portion of the bead is successfully extracted after image processing. In this process, the soot removal algorithm plays an important role in accurate weld bead detection, and adopts adaptive local gamma correction and gray color coordinates. Using this automatic recognition system, geometric parameters of the weld bead, such as its length, width, angle, and defect size can also be defined. Finally, on comparing the obtained data with the industrial standards, we can determine whether the weld bead is at an acceptable level or not.

• 한국산업융합학회 논문집
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• 제14권2호
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• pp.59-65
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• 2011

$CO_2$ Welding which uses $CO_2$ instead of inert gas is most widely used in industrial sites. Welding rod for $CO_2$ Welding is roughly divided into solid wire and flux cored wire. $CO_2$ Welding has higher efficiency than any other welding methods, and also economic and speedy to handle, that's why is used frequently for welding general structures. As most of studies about $CO_2$ Welding are focused on metallurgical changes of successful joints, they developed theories about the change of configuration on weld parts. This study is especially focused on not only the change of configuration on weld parts, but also the change of the penetrating depth through changing the position of welding torch. For inspection, applied AWS A5.20 E70-1 among welding wires and fixed moving angles of torch, but controled the values of voltage and the position of welding. Also Automatic Feed Mechanism is used for exact movement of material, specimen is a piece of steel for general structures. By measuring and analyzing the configuration of sliced section and the values of welding leg length and welding throat after welding, the outcome about the changes turned out.

• Journal of Welding and Joining
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• 제16권6호
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• pp.104-112
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• 1998

In the previous study, the countermeasure for welding deformation of bracket tilt is through up through experimental inspection for total process including welding process. For completeness of systematic examination of parts having sensitivity on welding deformation, the comparison and feedback between the result through simulation of welding process and experimental data is needed. In other words, it is necessary to control welding deformation that construct the prediction system for welding deformation through comparison and tuning with experimental data. In the present study, the application of FEA on welding process of bracket tilt with susceptibility to deformation is made and deformation behavior through change of welding sequence is focused on. It is used to improve the exactness of deformation analysis that three dimensional analysis for moving heat source, activated and deactivated bead element, and volume heat flux etc.

• 센서학회지
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• 제28권6호
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• pp.371-376
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• 2019

We have developed an acoustic resonance inspection system to inspect the welding defects in the mechanical parts fabricated using friction stir welding method. The inspection system was consisted of a DAQ board, a microphone sensor, an impact hammer, and controlled by a PC software. The system was developed to collect and analyze the sound signal generated by hitting the sample with an impact hammer to determine whether it is defective. In this study, 100% welded good samples were compared with 95%, 90%, and 85% welded samples, respectively. The variation of the completeness in welding did not affect the visual appearance in the samples. As a result of analyzing the natural frequencies of the good samples, the five natural frequency peaks were identified. In the case of the defective samples, the frequency change was observed. The welding failure detection time was fast enough to be only 0.7 seconds. Employing our welding defect inspection system to the actual industrial field will maximize the efficiency of quality inspection and thus improve the productivity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.135-137
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• 2004

In this study we'll deal with the small-sized metalized film capacitors with large capacity which head have $5mm{\times}5mm{\times}2.5mm$ dimension. The lead wire is used to weld at both sides of capacitors. At that time the position gap between the welding machine and lead wire supplier would cause the welding error. Also, during the tapping processing of metalized film capacitors, the interval error among the capacitors, the length error of lead frame attached at the capacitors, and the straightness distortion of the lead frame could happen. As mentioned, four kinds of error parameters will be measured and analyzed by using the automatic visual inspection system that is implemented with CCD camera, optical parts, background lighting, and image processing algorithms. Finally we are able to achieve success rate above 99% to detect the welding faults of capacitors in the field test.

• 한국산업융합학회 논문집
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• 제19권1호
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• pp.42-49
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• 2016

This study proposes a non-contact inspective technology based robot vision system for Faulty Inspection of welding States and Parts Shape. The maine focus is real time implementation of the machining parts' automatic inspection by the robotic moving. For this purpose, the automatic test instrument inspects the precision components designator the vision system. pattern Recognition Technologies and Precision Components for vision inspection technology and precision machining of precision parts including the status and appearance distinguish between good and bad. To perform a realization of a real-time automation integration system for the precision parts of manufacturing process, it is designed a robot vision system for the integrated system controller and verified the reliability through experiments. The main contents of this paper, the robot vision technology for noncontact inspection of precision components and machinery parts is useful technology for FA.