Monday  |  Lakeshore C  |  11:40 AM–12:00 PM

#19534, The Effect of Support Removal Sequence on the Residual Deformation of Additively Manufactured Thin Metallic Plates

In laser powder bed fusion (L-PBF) the complex thermal events taking place during a build cause residual stresses to develop during and after manufacture. In the case of quasi-2D thin metallic structure builds, these residual stresses can ultimately induce significant out-of-plane deflections. While the build platform supporting the parts during the process limits their distortion, the removal of supports from the platform (cutoff) activates redistribution of residual stresses in the parts causing eventual residual deformations. In this work, we use finite element analysis to predict deformations and stresses of thin Inconel 625 reinforced plates during the build process, throughout the support removal sequence, and after complete support removal. The Inconel plates, built in a portrait orientation, are supported by lateral buttresses and base supports which are then removed progressively after cooldown. It is found that the sequence of support removal significantly influences the process of residual stress redistribution, and thus the final deformed plate shape upon complete removal. Several nominally identical Inconel 625 experimental builds were also prepared by L-PBF for validation of the numerical predictions. Stereo digital image correlation (3D-DIC) was used to measure out-of-plane deflection throughout the support removal process with differing removal sequences. The experimental results showed close agreement to the numerical predicted residual shapes in each case. With specific support removal sequences, out-of-plane deflections comparable in magnitude and shape to those of a traditionally machined plate were achieved, whereas with other removal sequences a multifold increase of out-of-plane deflection was seen along with a change of residual deformed shape.

Pouria Khanbolouki   University of Illinois, Urbana-Champaign
Melissa Weihrauch   University of Liverpool
Eann Patterson   University of Liverpool
Christopher Sutcliffe   Meta Consulting LDA
John Lambros   University of Illinois, Urbana-Champaign