Abstract: An inlet manifold is for use in a laser powder bed fusion system having a build platform for carrying a powder bed and a pump or blower for supplying a gas flow in a direction relative to a surface of the build platform. The inlet manifold is made of a gas flow guide structure having a gas flow inlet to receive the gas flow and being comprised of a plurality of stacked gas flow guides, each being defined by top and bottom guide plates oriented downwards at an angle A relative to the direction of the gas flow for guiding the gas flow downwards towards a gas flow outlet. At least some of the top and the bottom guide plates have upwardly curved ends at the gas flow outlet to redirect the gas flow to be substantially parallel to the surface of the build platform.