Digital manufacturing system for printing three-dimensional objects on a rotating surface

A three-dimensional printer comprising:

• a hollow member having a wall and the hollow member includes a ledge movable between a first position and a second position;
• a first printhead mounted within the hollow member to enable the printhead to eject material onto an inner surface of the wall;
• a first driver operatively connected to the hollow member to rotate the wall of the hollow member about the printhead;
• and
• a controller operatively connected to the first printhead and the first driver, the controller being configured to operate the first driver to rotate the hollow member and to operate the first printhead to eject material onto the inner surface of the wall and build layers of material on the wall as the wall rotates about the first printhead and the controller is configured to adjust a rotation of the hollow member to enable gravitational force to cause the layers of material on the wall to move relative to the hollow member and the ledge in the first position prevents the layers of material on the wall from moving relative to the hollow member due to the gravitational force and the ledge in the second position enables the layers of material on the wall to move relative to the hollow member due to gravitational force.