Dissertation
Dissertation > Industrial Technology > Metallurgy and Metal Craft > Welding, metal cutting and metal bonding > Welding process > Arc welding

Image Analysis System of Metal Transfer of Gas Metal Arc Welding

Author YuLongHua
Tutor GengZheng
School Harbin Institute of Technology
Course Materials Processing Engineering
Keywords Metal transfer LabVIEW Image analysis Simultaneous
CLC TG444
Type Master's thesis
Year 2008
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Arc current and arc voltage reflects the process of physical changes in the arc from the physical. High-speed camera can get the image of metal transfer directly. Combining the images of metal transfer getting by the high-speed camera with the parameters of arc, we are able to display the physical processes which happen in the arc completely.As there is no analysis tool about images getting by high-speed camera, the joint analysis between the parameters waveform and images is almost empty, this paper designs a simultaneous analysis system about metal transfer images and welding electrical parameters of gas metal arc welding. The image analysis system of metal transfer is also established. The two systems are based on LabVIEW. By the two systems,we can carry out analysis of the welding process and get information about the quality of welding, then provide a reference guide on the online test of welding quality .The simultaneous analysis system can make real-time playback of welding images and welding parameters achieved, it is important that it can make simultaneous play through controlling the simultaneous window, which makes parameters correspond to metal transfer images and makes accurately judge on the transitional approach of the metal transfer, the changes of electrical parameters when the metal transfer occurred can be directly observed, all that can create favorable conditions for analysis of the influence of the metal transfer and quality of welding caused by electrical parameters. The image analysis system has the functions of saving a single image, showing three-dimensional images gray, measuring the length of arc and droplet diameter. Through the joint analysis of the simultaneous analysis system and the image analysis system, the growth rate of metal and metal transfer frequency can be measured.Taking MIG welding as an example, this paper made simultaneous analysis of electrical parameters and welding images, analysis only for images and the joint analysis for the whole process of welding. The transitional approach of the metal transfer was made by the simultaneous analysis system; the increasing rate of current of short circuiting transfer and the critical current when the change from drop transfer to spray transfer happened were identified by comparing images and the parameters waveform; by the joint analysis of simultaneous analysis system and image analysis system, the transition frequency of drop transfer, the speed of droplet growing up and the acceleration of the metal transfer were tested. Results showed that the system established is accurate and effective, powerful, interface realistic, easy to operate.

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