What powder property is most critical for achieving high part density in SLS printing?

The powder property most critical for achieving high part density in SLS (Selective Laser Sintering) printing is particle size distribution. Particle size distribution refers to the range of sizes present in the powder material and their relative proportions. A powder with a broad, well-graded particle size distribution, meaning it contains a mix of small, medium, and large particles, tends to pack more efficiently than a powder with a uniform particle size. The smaller particles can fill the voids between the larger particles, resulting in a higher packing density and a lower overall porosity in the powder bed. This higher initial packing density translates directly into a higher density in the sintered part because there is less void space to eliminate during the sintering process. If the powder has a narrow, uniform particle size distribution, the particles will not pack as efficiently, resulting in a lower density powder bed and a more porous, weaker final part. Therefore, controlling and optimizing the particle size distribution is paramount for achieving high-density parts in SLS printing.