Penelope: A Novel Prototype for In Situ Defect Removal in LPBF

A new laser powder bed fusion prototype for in situ monitoring of defects and in situ and inline flaw removal has been developed at and patented by Politecnico di Milano (Italy). This prototype allows the identification of a defective layer thanks to an innovative in situ monitoring approach that combines image and video-image data in the visible and infrared ranges.When an alarm is issued, the layer containing the defect is removed in situ and inline, thanks to a novel self-repairing system acting as a grinder on the powder bed. After this removal step, subsequent layers are additively produced starting from the healed height. By comparing specimens obtained with and without such intermediate layer removal, the aim of this preliminary study is to investigate the feasibility of the methodology, revealing that no discontinuity is introduced into the part by the novel inline removal operation. This solution is conceived to enable novel zero-defect and first-time-right capabilities in additive manufacturing.