Patent attributes
A metering apparatus and corresponding method meter a powder material in a three-dimensional (3D) printing system. The metering apparatus comprises a hopper with walls configured to contain a powder material, a metering roller, and a tool. The metering roller is located beneath an opening of the hopper. The metering roller and a given wall of the walls of the hopper are spaced apart by a gap therebetween at the opening; the gap in combination with rotation of the metering roller causes the powder material to flow from under the given wall of the hopper at a substantially predictable rate. The tool is positioned at the given wall where the flow emerges and is configured to force the powder material off of the metering roller to supply the 3D printing system with the powder material for printing a 3D object.