Method and apparatus for fluid flow for additive manufacturing apparatus

A method for operating an additive manufacturing apparatus, the method comprising:

• generating, via a body with a plurality of openings, a first flow region, a second flow region, a third flow region, and a fourth flow region in sequential adjacent arrangement from a build platform to a laser window, wherein the first flow region is proximate to the build platform, and wherein the fourth flow region is proximate to the laser window, wherein a reference distance extends between the build platform and the laser window, wherein the first flow region corresponds to between 0.1% and 10% of the reference distance, the second flow region corresponds to between 2% and 50% of the reference distance, the third flow region comprises at least 20% of the reference distance, and the fourth flow region comprises 20% or less of the reference distance;
• and
• flowing a flow of fluid, via the body, at separate flow rates in the respective first, second, third, and fourth flow regions to generate:
• a maximum spatial gradient between a minimum velocity of the third flow region and a maximum flow velocity of the second flow region or a maximum flow velocity of the fourth flow region of approximately 100 1/s;
• and
• a velocity ratio of 1/8 or greater between the respective first, second, third, and fourth flow regions.