Abstract: An additive manufacturing apparatus (10) includes (a) a light polymerizable resin unit comprising a surface on which a light polymerizable resin can be supported; (b) a light engine (17) configured to illuminate a region of the light polymerizable resin unit; (c) a carrier platform on which an object can be produced; (d) a drive assembly operatively associated with the carrier platform for advancing said carrier platform (12) and said light polymerizable resin unit away from one another as said object is produced; (e) a purge chamber (300) surrounding at least a portion of said light engine (17); and (f) a purge gas in said purge chamber, or a purge gas supply operatively associated with said purge chamber (300).

Abstract: A stereolithography apparatus includes a light transmissive window defining a build region in which a polymerizable resin can be supported, the window characterized by a transmission spectra curve having a low transmissivity region between first and second high transmissivity regions; a carrier platform positioned above the window; a drive operatively associated with the carrier platform and the window and configured for advancing the window and the carrier platform away from one another; an ultraviolet light source positioned beneath the window; at least one infrared heat source positioned beneath the window; at least one temperature sensor operatively associated with the build region and configured to sense (directly or indirectly) the temperature of a polymerizable resin in the build region; and a temperature controller operatively associated with the temperature sensor and the infrared heat source, the controller configured to intermittently activate the infrared heat source to an elevated temperature at