Lyon & Lyon
Method of and apparatus for making a three-dimensional product by stereolithography
 Apparatus and methods for stereolithographically forming a three-dimensional object includes a vessel for holding a building material and a smoothing member for forming a uniform coating over a previously formed layer of the object. The smoothing member has a plurality of blades. The smoothing member is swept over a previously formed layer of the object, in at least two directions. Different clearances between the lower surface of the smoothing member and the upper surface of the previously formed layer are used to provide a uniform coating for a subsequent layer over the previously formed layer. The sweeping velocity of the smoothing member can be varied. Retractable needles are attached to the smoothing member for adjusting a blade gap between the lower surface of the smoothing member and the surface of the building material. 
3D Systems, Inc.
B G G G B Y B
B29C G01F G05D G01F B33Y Y10T B29C
inventional inventional inventional inventional inventional additional inventional
Paul F. Borzo Charles W. Mark A. Thomas A. Abraham
Jacobs Modrek Lewis Lewis Almquist Liran