Purpose of the project
The main shape of the laser beam used in the Laser-Powder Bed Fusion technology is the Gaussian one, employed by all the currently produced machines. One of the main limitations of L-PBF technology is its low productivity compared to other techniques. To overcome this limitation, the trend is usually to increase the power of the laser beam or the scanning speed of the laser (main control factors of SLM technology). However, acting on these parameters can lead to the instability of the melt pool due to localized overheating and, in some cases, to the loss of alloying elements (if particularly volatile, such as Mg, Zn). All this leads to a reduction in the productivity of the entire process.
To overcome these problems it is therefore possible to act on the optimization of the laser beam spot, i.e. on its shape, and therefore on the power density distribution, passing from the classic Gaussian shape used on all PBF production L-machines, to the ellipse, ring and flat-top.
The aim of this project is to characterize the behavior of different materials depending on the laser beam shapes.
Development of the project
Cailabs developed the Beam shaper, which is the system capable of modifying the shape of the laser. Then, the characterization of the different materials subject to molding followed (especially the most critical ones due to the characteristics of the formation of cracks during printing, such as Inconel 939), according to different printing parameters.