Control of bead geometry using multiple model approach in wire-arc additive manufacturing (WAAM)

Wire-arc additive manufacturing (WAAM) is increasingly popular for the low-cost and rapid manufacture of large and complex metallic components due to its high deposition rate and material efficiency. However, its insufficient manufacturing precision impedes a wide application of this process. In order to improve the geometric accuracy of beads deposited by WAAM, a feedback control system based on the multiple model approach is developed. Different local models are identified to characterize the complex dynamics between the process parameter travel speed and the bead geometry. The developed control system is tested in the manufacturing of three different parts with variable geometry. It is demonstrated that the system effectively compensates for geometric errors (both width and height), and the three tested parts’ mean error is reduced by 78%. The system can also increase the productivity of deposition by avoiding requirements of low interlayer temperatures.