Apparatus for the manufacture of three-dimensional objects

An apparatus for manufacturing a three-dimensional object, the apparatus comprising:

• a powder tank;
• a stirring device configured to rotate within the powder tank about an axis of rotation, wherein the stirring device includes,
• a base plate, and
• a strut extending from the base plate into the powder tank, the strut including a leading portion having a leading edge with respect to the direction of rotation, and a trailing portion having a trailing edge with respect to the direction of rotation, the leading portion having an inner face facing the axis of rotation and into the powder tank, and the trailing portion having an inner face facing the axis of rotation and into the powder tank and forming an obtuse angle with the inner face of the leading portion, one or more blades extending from the inner face of the trailing portion into the powder tank and towards the inner face of the leading portion, each of the one or more blades forming an acute angle with the leading edge of the strut;
• and
• the powder tank further including an inner wall extending parallel to the axis of rotation and having an inner wall surface conforming at least partially to a portion of the shape of the base plate, wherein the strut is mounted to the outer periphery of the base plate such that upon rotation of the stirring device about the axis of rotation the leading edge of the strut sweeps the inner wall surface of the tank and lifts the powder within the tank.