A Study On Butt Automatic Welding Processes Of Spatial Seams With Welding Robot In Ship Assembling

The workload of welding counts more than40%of the construction of the hull. weldingis the key part of the ship building, and it directly related to the quality and efficiency of theship building. Welding automation can greatly improve the stability, welding quality, weldingefficiency, the working conditions of the workers of welding process, so it makes the shipwelding gradually developed in the direction of automatic welding.The three-dimensional curve welding seam in bow and stern ship closure calls forbetter welding technology. But in current domestic shipyards, the seam in bow and stern shipclosure can only be welded manually. This type of welding has negative points such aswelding difficulty, poor environment, uncontrollable welding quality, low efficiency. As thelimited inner hull space, useing welding robot to weld in the inner of the ship is not feasible.While the all-position welding, which can have unlimitied welding space, using welding robotin the outer of the ship, puts forward higher requirements about welding equipment andwelding technology. Through the experiment, we find the positive effect of the low frequencyrotating arc to the welding technology. It can increase the heat dissipation area to cool thedroplets rapidly in solidification, at the same time, it can obtain larger weld width, whichmakes it is mostly adaptable to the long welding seam with variable weld spacing. In thisprogram, the all-position welding with rotating arc and welding robot is developed.Furthermore, in the process of long seam welding, the heat deformation of the workpiece willmake the workpiece deviat or sink. The robot controller is developed to adjust this deviation.when the deviation is discovered, the operator can adjust the routine of the welding robotthrough the robot controller. The integration of the welding robot, welding, rotating arc aresuccessful finished, and it puts forward a automatic solution in the ship welding.Many experiments about the overhead welding are carried out, and the weld bead aretested in many detection methods such flexural strength, metallographic, X ray, Vickershardness. The result of the detection shows the bead is all in high quality. According to thetest, the The optimum process parameters are determined. The principle of regressionanalysis is used to establish prediction model which is the changeable process parameters ofwelding torch rotation frequency f, rotation diameter D, CTWD and workpiece spacing T on the width W and reinforcement RI of the weld bead. The statistical test and error analysis ofthe prediction model are also made in this paper. Finally, tne sensitivity analysis of weldingparameters are carryed out using developed prediction model.Finally, the ship simulation section according to the50:1ratio is processed and thewelding experiment is carried out. The result of the long welding seam in all position weldingshows in high quality. According to the actual engineering application, the method to weldship closure by using Longmen frame to carry a welding robot welding is put forward.