Fabrication of curved overhanging thin-walled structure with robotic wire and arc additive manufacturing (RWAAM)

Abstract

Purpose Robotic wire and arc additive manufacturing (RWAAM) is becoming more and more popular for its capability of fabricating metallic parts with complicated structure. To unlock the potential of 6-DOF industrial robots and improve the power of additive manufacturing, this paper aims to present a method to fabricate curved overhanging thin-walled parts free from turn table and support structures. Design/methodology/approach Five groups of straight inclined thin-walled parts with different angles were fabricated with the torch aligned with the inclination angle using RWAAM, and the angle precision was verified by recording the growth of each layer in both horizontal and vertical directions; furthermore, the experimental phenomena was explained with the force model of the molten pool and the forming characteristics was investigated. Based on the results above, an algorithm for fabricating curved overhanging thin-walled part was presented and validated. Findings The force model and forming characteristics during the RWAAM process were investigated. Based on the result, the influence of the torch orientation on the weld pool flow was used to control the pool flow, then a practical algorithm for fabricating curved overhanging thin-walled part was proposed and validated. Originality/value Regarding the fabrication of curved overhanging thin-walled parts, given the influences of the torch angles on the deposited morphology, porosity formation rate and weld pool flow, the flexibility of 6-DOF industrial robot was fully used to realize instant adjustment of the torch angle. In this paper, the deposition point and torch orientation of each layer of a robotic fabrication path was determined by the contour equation of the curve surface. By adjusting the torch angle, the pool flow was controlled and better forming quality was acquired.

Control of forming process of truss structure based on cold metal transition technology

“…In addition, the WAAM based on CMT technology can obtain more shape components than the traditional welding process, such as the component with a thin wall (Li et al , 2019) or suspended (Li et al , 2019) features. However, due to the lack of supporting structure, the size of the component is usually small.…”

Microstructure, Mechanical Properties, and Galvanic Corrosion of 10CrNi3MoV Fabricated by Wire Arc Additive Manufacturing

“…WAAM materials possess strong adaptability, and the manufacture of complex structures and large parts became an important direction based on the past simple thin-walled parts. Yifeng Li et al [10] successfully manufactured thin-walled parts with curved surface overhanging by using robotic wire and arc additive manufacturing (RWAAM) technology and proposed a practical algorithm, which was verified by a test case. The National Aeronautics and Space Administration (NASA) developed an arc-based liquid engine matrix and sheath process, which solved the difficult problems of traditional casting and forging processes that cannot be achieved [8].…”