Development of residual stresses in unsupported overhang printing

One of the difficulties in printing unsupported cantilever structures using laser powder bed fusion is the lack of control in the current processing protocol to minimise the development of residual stresses (RS) in the powder-printed area, which, if too significant, can cause superelevation beyond acceptable GD&T limits or even collision with the recoater. The aim of this presentation is to propose approaches to measuring and understanding RS development in cantilevered wall structures printed at an angle of 90-20^o. The approach combines printing parameters, optical imaging of the powder bed and post-print X-ray methods to identify the best strategies to mitigate RS. Different cases of simple and complex geometries printed in IN625 and SS316L are presented.