Abstract: An apparatus for fabricating integral three-dimensional objects from successive layers of photoformable compositions by exposing the layers of the composition through a semi-permeable film that allows creation of release coatings on the side of the film facing the composition.

Abstract: An apparatus and method for fabricating integral three-dimensional objects from contiguous layers of a photosensitive composition in an imagewise manner, with an additional photogelled portion or photohardened wall, or both, surrounding the three-dimensional object.

Abstract: Apparatus and methods for modulating light involving the formation of bubbles in a normally opaque dye solution contained within a cell. The bubbles are created in the dye solution by focusing a beam from a laser in regions of the dye solution thereby vaporizing a solvent in the solution. When the bubble is formed, the modulator becomes substantially transparent in the region of the bubble. If the focused laser beam is turned off, the bubble condenses and the modulator again becomes opaque in the region of the condensed bubble.

Abstract: A method and composition for forming investment casting patterns wherein thermally-collapsible microspheres are incorporated into the pattern composition. The patterns can be made either by conventional pattern forming techniques or by solid imaging techniques. After investing the microsphere containing pattern in the ceramic shell, the pattern and shell are heated, causing a collapse of the microspheres and thereby preventing cracking of the shell. The shell is then heated to burn-out the remaining pattern material and fire the shell, thereby creating a mold.

Abstract: An apparatus and method for fabricating integral three-dimensional objects from successive layers of deformable and photoformable compositions by exposing the layers of the composition through a tensioned, elastomeric transparent film, in a way that the weak bonds between the film and each newly solidified layer are broken by changing the tension on the film, thus allowing a new layer of deformable composition to be introduced between the film and the solidified layer.

Abstract: An apparatus and method for fabricating integral three-dimensional objects from successive layers of photoformable compositions by exposing the layers of the composition through a detachable flexible transparent film, one side of the film being in contact with the composition and the other side of the film with a rigid transparent plate, which guides and supports the film.

Abstract: An apparatus and method for fabricating integral three-dimensional objects from successive layers of photoformable compositions by exposing the layers of the composition through a semi-permeable film that allows creation of release coatings on the side of said film facing said composition.

Abstract: An imaging method and apparatus produces an integral three-dimensional object from a multiplicity of cross sectional portions of the object. The cross sectional portions correspond to photohardened portions of contiguous photoformed precursor sheets of a photohardenable liquid composition.

Abstract: In a solid imaging system, the beam of a relatively high-powered beam radiation source, and more particularly a laser, is modulated in accordance with its varying vector sweep speed so that substantially constant layer depth is maintained at all scanner speeds in a strip of photohardenable composition as it hardens and solidifies in response to the source's irradiation.

Abstract: An apparatus for cleaning the surface of a pipeline by grit blasting, particularly the surface of a leaking bell and spigot joint, prior to encapsulating the joint for leak sealing purposes. The apparatus is mounted to the pipeline and has drive means to both move the apparatus around the pipeline and reciprocate the grit blasting nozzle.