Optimization of Welding Parameters for GTAW Based Rapid Manufacturing

摘要

The most important problem in welding engineering is to find the optimal process parameters. For metal joining, optimization of the welding parameters is mostly related to the joint quality and the welding productivity. In the rapid prototyping based on gas tungsten arc welding (GTAW), the building of three-dimensional (3D) parts by depositing metal in layers is only possible if these parameters are nearly optimized. The goal is to build complex 3D parts, where unsuitable parameters will destroy the underlying geometry. The building of 3D part by welding is especially sensitive to excessive heat input. A finite element model (FEM) has been developed that correlates the influence of the different underlying substrate geometry to the welding process. The influence of the geometry is significant and cannot be neglected. Extensive experiments are designed and completed in order to verify the conclusions derived from the finite elements model results. A real-time adaptive controller of the welding parameters, based on the obtained results, is proposed. This controller is capable of adjusting the heat input and wire feeding speed in real-time according to changes in the geometry. In addition, the overall system performance is monitored and recorded by through-the-arc sensing in order to demonstrate the versatility and robustness of the controller.