Resumo Soldagem em ângulo de componentes estruturais com espessuras dissimilares por tradicionais procedimentos, manuais ou automáticos, de soldagem podem apresentar falta de penetração, mordeduras e perfurações. A ocorrência destes defeitos se deve ao uso de uma incorreta corrente de soldagem e à falta de robustez do procedimento de soldagem diante das possíveis irregularidades geométricas nas juntas. Além disso, a profundidade das mordeduras e a quantidade de perfurações são ampliadas quando se deseja aumentar a produção. Isso se deve ao incremento da potência elétrica do arco para manter constante a quantidade de material depositado na junta em função do aumento da velocidade de soldagem. O presente artigo propõe o uso da técnica de oscilação longitudinal da tocha de soldagem, conhecida na literatura por switch back, para aumentar a produção com qualidade na soldagem. Foram usadas trajetórias de soldagem do tipo linear convencional e switch back de três passes com velocidade da tocha constante e variável (velocidade de avanço quatro vezes maior que a de retorno). O critério de aprovação dos cordões de solda foi baseado nas normas ISO de soldagem. Os resultados evidenciaram um aumento não significativo de produção com o uso da técnica switch back do tipo velocidade constante da tocha.

Abstract Angle welding of structural components with dissimilar thickness by traditional, manual or automatics, welding procedures can show lack of penetration, undercut and perforations. The occurrence of these defects must be the incorrect use of the welding current and the lack of robustness of the welding procedure among the geometrical irregularity possibilities in the joints. In addition, the depth of the undercut and the quantity of the perforations are enlarged when the increase of the production is wanted. This occurs due the electrical power increment from the arc to keep constant the quantity of the material in the welding joint to get higher the welding speed. This work apply the longitudinal oscillation from the welding torch known on the literature as switch back, to increase the production with quality in welding. Were used trajectories of the type linear conventional and switch back of three steps with constant and variable torch velocity (forward velocity four times faster than the return). The weld seams approval standard was based in the welding ISO. The results showed a non-significant increase of the production with the technique switch back of the type constant speed from the torch.

The additive manufacturing processes emerged at the end of the last century and became popular by low-cost 3D printers. The most used printers work on a cartesian configuration, but recently were launched delta machines. These 3D printers use a more complex control system due to their trajectories generation but may present some advantages over the cartesian configuration. To increase the knowledge about additive manufacturing, a comparative study with cartesian and delta printers was performed to evaluate the performance on printing a testing part. Three samples were produced in each printer and compared based on surface quality, manufacturing time, mass and dimensional measurement. The printed objects were 3D scanned for comparing the digitized geometry by aligning the point cloud generated to its virtual 3D model. The parts produced in delta printer obtained better surface quality, while cartesian printer provided better dimensional accuracy. The results also showed that the variation of the mass and time to produce the parts were not significant.