Laser beam shaping in time, space, and wavelength for powder bed fusion

Ali Gökhan Demir

Associate Professor, Department of Mechanical Engineering, Politecnico di Milano

Le 12 juin 2025 à 13h30, To be communicated

Abstract: 

Amongst the metal additive manufacturing processes laser powder bed fusion (LPBF) is arguably the most mature one for industrial use. The rapid growth of the LPBF technology is closely aligned with the developments in the computational capacity but also thanks to the emergence of the fiber lasers as industrial tools. While the previous allowed to calculate and execute lengthy path programming tasks, the latter allowed for a robust and reliable process previously not available. The contemporary LPBF machines make use of multiple fiber lasers with beam steering optics relying on the simple and yet effective principle of vector-based scanning, producing kilometres of melt tracks that generate 3D functional parts. On the other hand, the LPBF process is limited to available material types and often the products require post-processing stages for surface quality and the mechanical properties. In the meanwhile, the laser technology has taken a new leap towards more flexible control in space and time with new wavelengths in visible range. The next generation of metal additive manufacturing processes can further exploit these control possibilities for higher quality parts with controlled microstructure. This talk will provide an overview of research carried on in the field of LPBF exploiting novel strategies for laser beam control. In temporal domain practical examples exploiting pulsed wave emission as well as arbitrary waveforms will be discussed. In the spatial domain novel beam profiles exploiting core/ring as well as arbitrary beam shapes will be demonstrated. The overview will aim to allocate the different solutions to tackle processability, improve feature resolution, provide microstructural control, decrease crack susceptibility, and increase productivity. 

Biography: 

Ali Gökhan Demir is an Associate Professor of Manufacturing and Production Systems with the Department of Mechanical Engineering at the Politecnico di Milano. He completed his PhD in Mechanical Engineering at the Politecnico di Milano in collaboration with the University of Cambridge in 2014. He carries out research within SITEC - Laboratory for Laser Applications on laser-based manufacturing processes with an emphasis to the light-material interaction mechanism in temporal, spatial and wavelength domains. His research interests cover laser welding, micromachining, and additive manufacturing, developing of novel processing solutions for improving processability and precision, as well as the to produce multi-material structures. He leads the LaserEMobility section of AITeM - Italian Manufacturing Association dedicated to the development of laser processes for EV manufacturing. He has contributed to more than 150 peer-reviewed articles and several patents. He helped with the development of laser-based manufacturing processes for industrial companies operating in automotive, electric mobility, electronics, energy, and aerospace sectors. He serves as the Associate Editor to Additive Manufacturing Letters.