Niobium is an important material for high temperature applications, in space, in superconductors or in chemical processconstructions. Laser-based powder bed fusion of niobium (PBF-LB/M/Nb) offers new opportunities in design, though it isstill an expensive technique. The build-up rate is an important factor for economical manufacturing using PBF-LB/M/Nb.It is largely influenced by variation of process parameters, affecting the heat flow during the manufacturing process. Inthis work, an empirical model for PBF-LB/M/Nb is developed. Based on this model, manufacturing parameter sets usingdifferent volume build-up rates are predicted and confirmed. They enable the manufacture of parts with homogeneousand crack-free microstructure with more than 99.9\% relative density. Tensile and hardness tests of specimens, which weremanufactured using different parameter sets, are performed to determine the effects of the build-up rate—and thus theheat flow during manufacturing—on different mechanical properties. The ultimate tensile strength and yield strength ofas-manufactured specimens reach values up to 525 MPa and 324 MPa, respectively, while the elongation at break rangesbetween approximately 8 and 16\%. The Vickers hardness of all specimens was in the range of 149±8 HV0.1. In addition,the microstructure of the manufactured samples is investigated by means of light as well as scanning electron microscopy.