3D Printing Primer

Chapter 3. Powder-Bed (Granular) Processes

Process name	Description of method	Machine cost	Upkeep cost	Open source?	Primary distributors
Powder-bed or granular processes	Bind or melt layers of powder together. Various materials used.	High	High	No	Commercial: 3D Systems and ExOne See also: Reneshaw, SLM, Concept Laser, Arcam, EOS

One of the more diverse classes of 3D printer are what I will generalize as powder-bed processes, though many different commercial names are applied to several specific variations of this sort of approach. You will also find them described as granular methods, in that powders are used rather than liquids or solid filaments.

In a powder-bed printer, two actions are repeated alternatively throughout the duration of the print. The first action involves sweeping a thin, uniform layer of powder from a reservoir across a build platform. This recoating step is generally performed using a doctor blade or roller, which feeds powder from a supply platform to the build platform.

In the second action, the freshly swept powder layer is selectively melted, bound, fused, or otherwise glued together. After this, the build platform lowers, and the cycle repeats itself as a new layer of powder is swept across the surface for patterning. The final result might be a solid part (perhaps fused to the build platform) or a porous/weak part that requires additional infiltration/processing to densify/strengthen it.

Figure 3-1 shows a powder-bed printer for the production ...