A method of surface equalization of a part formed by 3D printing, comprising: providing a part-containing tank having a first flat side and a second flat side, wherein the first flat side is opposite the second flat side; and an oblong portion, wherein the oblong portion has a first oblong side and a second oblong side; wherein a motor mount is attached to an outer surface of a base in a location offset from a center of the base of the part-containing tank, wherein at least one eccentric motor is attached to the motor mount, and wherein a plurality of springs is attached to the part-containing tank; filling the part-containing tank with a media; generating a motion on the part-containing tank in a z-direction; wherein the flow of media in the part-containing tank is directed away from an inner surface of the part-containing tank by structural features on the inner surface of the part-containing tank; activating the motor to rotate the media in the part-containing tank; placing a part in the part-containing tank; suspending the part in the media within the media; equalizing the surface of the part; characterized in that the part-containing tank has a first diverter proximate an exhaust surface edge of the media and has a second diverter proximate an intake surface edge of the media; and the first diverter is located vertically above the second diverter or a plurality of semi cylindrical guide ribs is located running across an upper portion of the first oblong side to the upper portion of the second oblong side, wherein the plurality of guide ribs are spaced at intervals longitudinally across the oblong portion of the part-containing tank. providing a part-containing tank having a first flat side and a second flat side, wherein the first flat side is opposite the second flat side; and an oblong portion, wherein the oblong portion has a first oblong side and a second oblong side; wherein a motor mount is attached to an outer surface of a base in a location offset from a center of the base of the part-containing tank, wherein at least one eccentric motor is attached to the motor mount, and wherein a plurality of springs is attached to the part-containing tank; filling the part-containing tank with a media; generating a motion on the part-containing tank in a z-direction; wherein the flow of media in the part-containing tank is directed away from an inner surface of the part-containing tank by structural features on the inner surface of the part-containing tank; activating the motor to rotate the media in the part-containing tank; placing a part in the part-containing tank; suspending the part in the media within the media; equalizing the surface of the part; characterized in that the part-containing tank has a first diverter proximate an exhaust surface edge of the media and has a second diverter proximate an intake surface edge of the media; and the first diverter is located vertically above the second diverter or a plurality of semi cylindrical guide ribs is located running across an upper portion of the first oblong side to the upper portion of the second oblong side, wherein the plurality of guide ribs are spaced at intervals longitudinally across the oblong portion of the part-containing tank.