Productivity optimization in laser powder bed fusion of 316L by combining beam shaping and increased layer thickness

In recent years, beam shaping has been recognized as an effective strategy for increasing the total productivity of the laser powder bed fusion process. The majority of the modified intensity distributions have wider beam profiles, allowing for increased hatch spacing, thereby directly affecting the build rate. However, most research on beam shaping productivity focuses on optimizing scan speed and hatch spacing, while ignoring the influence of layer thickness on the total productivity. This work discusses the effect of layer thickness variations on an increase in productivity in the 316L stainless steel for both a Gaussian beam and a ring-shaped beam. While for 30 μm layers, the ring beam has a larger process window and a higher build rate, for thicker layers, an equally powerful ring-shaped beam is shown to be not more productive than the conventionally shaped Gaussian beam, owing to the flat bottomed melt pool requiring slower scan speed to reach the desired melt pool depth. However, when a slight amount of porosity is accepted, the ring beam showed a significantly higher increase in the build rate, owing to the reduced amount of pore forming locations in the part. Thus, whether Gaussian or shaped beams are better suited for thicker powder layers is dependent on the desired applications and corresponding required material densities.