@phdthesis{Nguyen2022, author = {Nguyen, Qui Lam}, title = {Tool path planning for wire-arc additive manufacturing processes}, doi = {10.26127/BTUOpen-5982}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-59827}, school = {BTU Cottbus - Senftenberg}, year = {2022}, abstract = {Among variants of AM technology, wire-arc additive manufacturing (WAAM) process suitably produces bulky metal parts with a medium complexity. Although WAAM shows a great potential, this process has not been fully explored, and it is therefore a worthwhile subject to further investigate. This monograph engages with tool path planning for the WAAM process and existing problems in WAAM are subsequently addressed, as following: The existing overlapping models yield an uneven surface due to the inner beads overlapping with two neighbor beads while the outers have only a one-sided overlap. New mathematical models are established to obtain optimal distances between adjacent weld beads and to make surfaces more even. Lightweight structures have high strength as compared to their weight. Producing these structures by WAAM results in imperfections because of uneven weld beads - an inevitable phenomenon when starting a new track. A new tool path strategy to produce lightweight structures is developed using contour patterns, which transforms any arbitrary geometry into that of a continuous path. Unfortunately, voids are formed at junctions when using contour patterns. An adaptive correction using machine learning is then developed to overcome this defect. Large overhangs and inclined features are out of reach of WAAM when operating in the x-y plane in Cartesian system. This limits the ability of the WAAM process. To overcome that, each overhang feature should be welded with a distinct direction. This approach is realized within the robot based WAAM process. Establishing the kinematics of the FANUC robot arm and the positioner helps compute the new coordinates, the angular displacements of the positioner, and the orientation of the torch. The proposed strategy is examined through the construction of an overhang part. The capabilities of the multi-axis deposition are extended by constructing curved thin-walled structures. Irregular thickness layers are deposited by controlling the travel speed, resulting in a different deposition rate. The curved thin-walled structures can be properly fabricated by combining a multi-axis deposition with non-uniform thickness layers. Bonding quality as well as geometric accuracy are also to be investigated. To ensure geometric accuracy, a compensation strategy is developed. The performance of the proposed algorithm is validated on different geometries. This monograph will conclude with a summary of this work's main achievements and contributions as well as outlooks on future research.}, subject = {Wire-arc additive manufacturing; Lightweight structures; Curve thin-walled structures; Multi-bead overlapping models; Lichtbogenadditive Fertigung; Leichte Strukturen; Gekr{\"u}mmte d{\"u}nnwandige Strukturen; {\"U}berlappende Modelle; Rapid Prototyping ; D{\"u}nne Schale; Lichtbogen; {\"U}berlappung}, language = {en} }