Visual Sensing And Penetration Information Extraction Of Wire-filled TIG Welding Process

Real-time acquisition of the penetration state during the welding process is the basis for welding penetration control,in the one-side welding both sides formation welding process,skilled welders can judge the current penetration state according to the shape of the weld pool and the fusion hole.It can be seen that the weld pool and the fusion hole contain a large amount of penetration information.However,at present,the fusion holes is only used in manual welding.In order to achieve penetration control in automated welding,it is necessary to study the shape of weld pool,fusion holes and their dynamic behavior.In this paper,an experimental platform for one-side welding both sides formation TIG welding is built,it consists of welding system and synchronous acquisition system of visual and electrical parameters.A composite filter system consisting of 1064nm narrowband filter and neutral dimmer was designed.The arc interference can be effectively filtered,and clear images of weld pool and fusion holes can be obtained,The size of the image is effectively improved and the clarity of the image is increased by using the close-up ring.Experiments of 3mm thick Q235 carbon steel plate were carried out and images and electrical parameters during welding were collected.The image processing algorithm is designed to effectively acquire the edges of weld pool and fusion holes.For the image of fusion hole,the width and length of fusion hole are taken as its characteristic values.Failure modes of fusion hole at different welding speeds are analyzed.According to the length and width of fusion hole,the failure modes are divided into transverse instability,longitudinal instability and overall instability.At the same time,the relationship between droplet transfer frequency and hole stability was studied.When the droplet transfer frequency is 5 Hz,compared to 1 Hz,the dimensional stability of fusion hole is better.For the images of weld pool,the contour angle of the weld pool tail and the half-length of weld pool are taken as its characteristic values.The results show that the contour angle of the tail is large when the weld pool is not penetrated,and the half-length of the weld pool is short,the contour angle of the weld pool tail is usually above 140 degrees.When the weld pool is overpenetrated,the contour angle of the tail is small,usually below 70 degrees,and the half-length is large,about 7 mm.When the contour angle of the tail of the weld pool is in the range of 80?120,the workpiece penetrates well.And when the contour angle of the weld pool tail is about 100 degrees and the half-length of the weld pool is about 6 mm,the penetration condition is the best.When the penetration state changes,the contour angle of the weld pool and the half-length of the weld pool change greatly.The experiment of variable butt gap was designed,and the change of penetration state during welding process was successfully judged by the contour angle of the weld pool tail and the half-length of the weld pool.