Analysis Of Characteristics Of Metal Plume Image During High-power Disk Laser Welding

With the rapid development of modern industrial manufacture, high-effective,smart and environmental processing technology is emphasized gradually. Laser welding is a significant laser processing technology. Laser welding can achieve the deep penetration welding and rapid welding with high energy beam focus, which other welding modes can not achieve. Laser welding equipment can be assembled flexibly and achieve supermatic welding in industry applications. Comparing with the traditional laser equipment, disk laser has distinct advantages at the beam quality,processing efficiency,the weight and the volume of the equipment.Metal plume is an avoidless phenomenon at the processing of the high-power laser welding. Metal plume do refraction,reflect,scatter and absorb to the incident light, it impacts the radiation energy of the surface of the workpiece and the quality of laser welding. Therefore, study the relationship of metal plume phenomenon and the quality of laser welding do a great research significance to achieve the online monitoring of the quality of hight power laser welding. According to the characters of fast welding speed,hight power density of laser beam and strong metal plume radiation light of the hight power(≥10kW) disk laser welding. Subtle changes of metal plume at the smalltime interval can be obtained by using high-speed vision sensor for dynamic image sequences of metal plume. Convert the original images to grayscale images, using wiener filtering, binary image, morphological opening operation processing, non-splash binary images of metal plume can be obtained. Areas and heights of the metal plume can be calculated form these images. Using the metal plume images of non-splash binary and the metal plume images of gray, splashless gray images of metal plume can be obtained, and angle of the metal plume can be get form these images.By calculating the average of the first difference of the area and height of metal plume at different welding quality regions,counting the probability of appearing big first difference of the area and height of metal plume; analysing the angle curve at different welding quality regions. Experimentation proves that these three characters above can reflect the relationship between the metal plume and the welding quality. This thesis analyzes the formation mechanism of metal plume, the relationship between the welding quality and the characters of metal plume. It provides experimental and theoretical bases to achieve on-line quality monitor, and has great theoretical and practical significance.