Multi-path/Multi-layer Welding Off-line Programming Technology And Applied Research

Robotic multi-path/multi-layer welding technology is widely applied in automobile, engineering machinery, shipbuilding and other fields. For large workpiece welding, manual programming teaching efficiency is low, and it hard to guarantee the accuracy. This article with the support of production research in Fujian province’s major projects do a research for multi-path/multi-layer welding off-line programming technology in the application of large weldments. So far the function of Off-line programming software on the market is simpler, only simulation for single welding,and can’t meet the multi-path/multi-layer welding programming. Off-line programming has two prominent problems in the application of thick plate welding. On the one hand, when mass production, the processing error of the workpiece and the positioning error of workpiece all will influence the accuracy of the off-line programming planning path. On the other hand, Off-line programming software lacking of multi-path/multi-layer welding process parameters planning, and welding process parameters has a greater influence on welding quality, According to the above problems, this article mainly researched on three aspects of off-line programming technology, including groove detection, welding process planning,multi-path/multi-layer welding path planning. Then make a secondary development in RobotStudio software, using this software carry out the simulation and the actual welding test for loader girders.Groove detection is mainly based on the two-dimensional laser displacement sensor to gain the groove image information of workpiece. Through image processing and groove feature recognition methods to distinguish groove type and calculate the groove feature parameters. And through the groove section and location information,rectify the off-line programming robot path planning in advance, to ensure the accuracy of the robot welding position, solve the machining error of groove and the influence of position error.Welding process planning is mainly focus on the welding current, welding speed,dry elongation, swing etc. welding parameters planning. Using cubic polynomial fitting method, gain the wire feeding speed and the welding current data in the welding expert database,through the relation between the substitution from which the weld cross-sectional area and the relation between the welding current and welding speed, and the correctness of this formula is verified by experiment. Through welding experim, analyze the influence for various welding parameters forming welds, provide a reference basis for welding parameter planning.Multi-path/multi-layer welding path planning through planning layer number,pass number, using equivalent area method to calculate the offset of each welding torch welding and torch offset angle, and each of the base path by homogeneous transformation matrix translation transformation and rotation transformation, to gain the multi-path/multi-layer in every path.Through welding sequence planning,optimize the robot walking paths, improve the production efficiency and welding qualityFinally, take Loader frame girder as an example, using multi-path/ multi- layer welding off-line programming software planning out all girder welding path and welding technology parameters, and weld it. From the actual effect of welding can prove the practicability of the software development.