Analysis and compensation of shrinkage and distortion in wire-arc additive manufacturing of thin-walled curved hollow sections
- Journal Article
Curved hollow sections are used in numerous applications from lightweight space frames to pipings in process engineering. In conventional manufacturing, such structures are produced mainly by metal forming or casting. Despite ongoing efforts in rapid tooling technologies for casting and flexible forming processes, there is a demand for dieless manufacturing of curved hollow structures, as this would allow to produce parts with greatly reduced lead-times, e.g., as on-demand spare parts and on construction sites using mobile equipment. Wire-arc additive manufacturing (WAAM) processes with multi-axis deposition can be used in this case. This process typically draws upon the gas metal arc welding (GMAW) process with cold metal transfer (CMT) technology. Thin-walled metal parts produced by WAAM may show deviations to the target geometry due to material shrinkage and distortion, which may entail tedious trial-and-error compensation. This study analyses shrinkage and distortion in curved hollow sections with different cross sections and curvature radii both experimentally and with a thermo-mechanical finite element model. Based on these findings, a novel method for the compensation of shrinkage and distortion for thin-walled hollow parts is put forward and validated. The correction method draws upon the geometrical deviations that occur when the part is produced based on the CAD geometry, and computes a correction to the CAD geometry, which is used to define the welding path for a part with improved accuracy. The results show that the geometry of the manufactured part can be corrected to tolerances in the range of the waviness of the surface by applying the proposed correction. Show more
Journal / seriesAdditive Manufacturing
Pages / Article No.
SubjectAM; WAAM; Curved hollow sections; Distortion compensation; Residual stresses
Organisational unit09706 - Bambach, Markus / Bambach, Markus
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