Mechatronics Design Of Pipeline All-Position Automatic Welder And Research On Its Welding Technique

Transport industry includes pipeline, aviation, railway, road and watertransport. Pipeline transport is one of the goals which is being emphatically developed by our government. Pipeline is a main part of pipeline transport. Pipe connection by welding is the key work in pipeline construction. So it is clear that research on the technology of pipeline all-position automatic weld is of great significance.Pipeline all-position automatic welder is used for welding long-distance transport pipeline. It has the advantages of reliable welding quality, high welding efficiency and reducing worker's labor intensity, etc. It includes a guide track, a welding carriage (or two carriages), a set of automatic control system and other supplementary instruments. It uses CO2 gas (or CO2+Ar2 mixture gas) as protective atmosphere.This paper is to make use of basic principles and design thought of mechatronics to analyze the dynamic characteristics of pipeline all-position automatic welder servo system. The design method of mechatronics makes the whole system of automatic welder to have not only functions of mechanical motion and welding, but also functions of information-examining, handling, adjusting and controlling. By using built-in hardware and software, the automatic welder has achieved flexible automation.Welding technique is also one of the important topics discussed in this paper. The proper values of welding parameters are determined by welding tests. The half girth seam is first divided into 6 segments. For each segment, a great deal of welding tests are carried out with different values of welding parameters to find out the proper and typical values of welding parameters suitable for different pipe diameter, different pipe wall-thickness and different seam position. Then, the determined welding parameters are input into the computer of automatic welder and the computer will finish curve fitting automatically. With the fitting curves, the automatic welder, when in course of welding, can continuously change welding parameters based on the current welding position.