Improving metal additive manufacturing part design and final part precision using feedback from X-ray computed tomography

Additive metal manufacturing processes, such as laser powder bed fusion, still show difficulties when producing overhang features or internal structures such as channels or bores. Channels are often mutilated by sag defects and dross formation at their upper part, when the channel-axis is close to parallel to the base plate and in the particular case when support structures cannot be used as it would be impossible to remove them after the build. The problem is still not completely solved, although various design guidelines have been developed for various processes and materials in use. So far, a general approach is to tweak the processing parameters or to orient the design on the build plate to reduce downfacing regions at the most critical features of the parts. This work proposes to use feedback from X-ray computed tomography measurements and a new evaluation approach for the additive manufacturing process-chain to obtain improved geometrical accuracy of internal channels. Preliminary results on the evaluation are presented, with the future scope of reducing sag and dross defects by adapting the channels and bores during the design stage.status: publishe