Abstract: A method of reducing performance deviation in at least one additive manufacturing apparatus during production of parts is provided. Each apparatus has a light source configured for polymerizing a light polymerizable resin with sequential doses of patterned light to produce a 3D object. The light source has an assigned nominal emission data, such as an expected or preset standard emission data, and actual emission data. The method includes modifying at least some of said light doses in said at least one apparatus during production of parts therein to compensate for a deviation of said actual light source emission data from the assigned nominal emission data.

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).