Lower gas flow injection system and method for additive manufacturing system

A method for additively manufacturing an object comprising:

• disposing a build platform in a lower portion of a chamber defined by a housing;
• depositing a bed of a powder material on the build platform positioned at a first elevation within the chamber;
• positioning a lower gas inlet a distance above or below the build platform in an upstream end portion of the chamber, the lower gas inlet supplying a lower gas flow to the chamber;
• directing via a contoured surface extending tangentially between the lower gas inlet and the build platform the lower gas flow from the lower gas inlet toward the build platform, the lower gas flow flowing along the contoured surface and discharging from the contoured surface in a direction substantially parallel to the build platform;
• disposing an upper gas inlet in a first side wall of an upper portion of the chamber, the upper gas inlet supplying an upper gas flow in the direction substantially parallel to the build platform;
• regulating via one or more gas delivery devices coupled to the lower gas inlet and to the upper gas inlet, one or more flow characteristics of the lower gas flow and the upper gas flow;
• and
• applying a focused energy beam to at least a portion of the bed of the powder material deposited on the build platform to form a solidified layer.