Fabrication of filigree parts via laser powder bed fusion: From melt spots to stents

Laser powder bed fusion (LPBF) faces challenges when fabricating intricate structures with thin elements, comparable to the laser beam size, and thus requires precise deposition of melt spots. We devised a method for creating a Fe-15Mn-0.8C filigree structure via LPBF with a pulsed Gaussian laser beam. Initially, single melt spots were deposited to determine the optimal exposure time depending on laser power and laser spot size. Arrays of single melt tracks were then deposited, varying laser spot size, power, and point distance between spots, with the depth and width of each melt pool quantified. Through correlation analyses, key parameters were identified: exposure time and laser power for uniform melt spots, and laser power and point distance for melt pool depth. Utilizing the normalized enthalpy criterion, optimal parameter values were determined. We successfully LPBF-fabricated fully dense, 80 µm diameter pillars representing the simplest filigree structures and finally a complex stent structure with 99.5 % relative density. This approach can be adapted to other materials and additive manufacturing technologies using pulsed laser beams, streamlining experimentation.