Abstract
The wire and arc additive manufacturing (WAAM) is an additive manufacturing route in which the part is fabricated by layers composed by multiple arc weld beads side-by-side. One of the current challenges for the actual implementation of this DED-type additive manufacturing, with its full capabilities, to revolutionize state-of-the-art manufacturing is the geometric prediction of the layers during deposition. One of the alternatives that help in this prediction is the use of several coupled optical sensors that read the conditions online. However, this method can have disadvantages such as a decrease in the degrees of orientation material deposition freedom as well as an increase in the capital cost of equipment. Another way to predict layer geometry is by creating a geometric results database and developing mathematical equations to represent the most interesting depositing conditions and use it to simulate and predict future deposits geometries with a dedicated algorithm integrated in the deposition trajectory generation CAE software. This paper demonstrates a methodology for creating this database from hands-on experiments to optimize weld bead overlap based on measuring and comparing overlapped deposition areas between weld beads and their center points. The generated algorithm calculates the optimal offset between passes to result in a layer with homogeneous height. The algorithm was fed with data obtained in the single weld bead deposition, subsequently using the algorithm was calculated the ideal distance in function of the overlap area. In addition, it was variated adding and decreasing 10% in the calculated distante in order to evaluate the algorithm precision and accuracy. The overlap beads were built with a CMT power source with a ER70S6 wire feedstock under conventional deposition conditions. The results showed that the algorithm is a reliable approximation of the real geometry, presenting low error. With the second-degree equation used as model it was possible to create a method to define the optimal overlap condition and mitigate welding defects like under cut, lack of fusion and other common to these depositions.
Keywords: Additive manufacturing; Simulation; WAAM; Directed Energy Deposition; MIG; TIG.
Reference:
ROCHA, P. C. J.; SCHWEDERSKY, M. B.; MACIEL, P. C.; GALEAZZI, D.; SILVA, R. H. G.. Welding Beads Overlapping Algorithm Dedicated to Waam. 26th ABCM International Congress of Mechanical Engineering. November 22-26, 2021. Florianópolis, SC, Brazil