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In the processes of automatic welding of container girders, the uneven strong reflection on the workpiece surfaces, arc light, splash, and smoke easily led to inaccurate or difficult identification of weld deviations, so a welding seam tracking system for gas metal arc welding of container girders was proposed. Based on a low-cost structured light vision sensor, a highly robust welding seam feature extraction model was established. The linear slope of the laser stripes was used by the model for optimizing the random sampling processes of the random sampling consistency algorithm which achieved stable extraction of weld feature in complex environments. The welding test results on the surface of uneven and strong reflective workpieces show that the average detection errors of the method in the Y and Z directions are as 0.22 mm respectively and 0.19 mm with the welding parameters of 300 A, 29 V, and 1m/min, which achieves stable high precision welding seam tracking. [ABSTRACT FROM AUTHOR]

To improve the automation, welding efficiency, and welding quality of duckbill welding of the cotton seeder, this study designed a cotton seeder duckbill welding robot. According to the characteristics of the duckbill weldment and welding requirements, the overall structure of the welding robot was determined, including the girdle feeding mechanism, static duckbill feeding mechanism, hinge feeding mechanism, welding fixture, welding actuator, and control system. To realize the continuous automatic feeding, positioning, fixing, welding, and unloading of the workpiece in the duckbill welding, the feeding mechanism adopts the method of cooperative cooperation of inductive proximity switch, electromagnet, and cylinder. The main body of the welding fixture adopts the pneumatic clamping method; the welding actuator adopts the synchronous belt module electric drive so that the welding torch can move in a straight line along the X axis and the Z axis. The welding process of the duckbill was simulated by Simufact Welding software, and the deformation and stress changes of the weldment were compared and analyzed when the single-sided single welding, the bilateral symmetrical double welding torch, two welding forms, and two welding process parameters were used to determine the welding process parameters of the welding robot. The prototype was made and the welding test was carried out. The test results show that the duckbill welding robot of the cotton seeder has stable feeding, solid clamping, accurate positioning, and high welding efficiency. According to the national standard, the appearance of the duckbill weld is inspected. The surface of the duckbill weld and the heat-affected zone has no cracks, incomplete fusion, slag inclusion, crater, and porosity. The forming quality of the welded parts is good. The design of the duckbill welding robot for cotton seeder is helpful in solving the problems of cumbersome positioning and clamping and low efficiency in manual and semi-automatic duckbill welding robots, which provides a strong guarantee for the large-scale and standardized welding production of the dibbler duckbill. [ABSTRACT FROM AUTHOR]

Damaged surfaces are normally recovered by means of processes of welding; they normally have complex geometries and are located in positions that are unfavourable for welding. Automated welding is the natural alternative as it presents advantages when compared with the manual process, such as reductions in the time and total cost of the recovery, better control of the geometry of the recovered surface, better uniformity and welding quality. Automated welding using the plasma process with automatic wire feed, although it provides excellent geometric and surface quality for the deposits, a significant reduction in welding defects and an absence of spatter, is very sensitive to variations in the torch-piece distance and to changes of welding position. In this context, the present work deals with an analysis of the changes made to the position of the wire in relation to the electric arc and the weld bead, to the orientation of the torch in relation to the surface to be welded and to the welding parameters that make the plasma welding process more robust due to geometric alterations to the surface to be welded. The practical results achieved in the most critical situations, from the point of view of welding damaged surfaces, are presented with the objective of validating the changes proposed for the fed plasma process. [ABSTRACT FROM AUTHOR]