Abstract: An additive manufacturing system may include an irradiation device configured to emit an energy beam having a manufacturing power level selected to additively manufacturing a three-dimensional object by irradiating a powder material, and a controller configured to perform one or more beam alignment operations when irradiating the powder material. The irradiation device may include a beam source, one or more beam positioning elements, a beam splitter configured to split a measurement beam from the energy beam, and one or more beam sensors configured to determine one or more parameters of the measurement beam. The one or more beam alignment operations may include determining position information of the energy beam based on the one or more parameters of the measurement beam, and aligning the energy beam with an optical axis of the irradiation device by adjusting a position of the one or more beam positioning elements based on the position information.