Abstract: Apparatus for and related methods of forming three-dimensional objects out of a building material, which is normally solid, but which is flowable when heated. In one embodiment, a support material is used to fill in portions of layers which are not to be solidified as part of the object, thus providing support to otherwise unsupported portions of other layers. Advantageously, the support material is also normally solid and flowable when heated, and has a lower melting point than the building material enabling the support material to later be removed without damaging the object. In an alternative embodiment this support material can be used to build a support such as a web support, or the like, for supporting an object surface from a second surface.

Abstract: Apparatus for and related methods of forming three-dimensional objects out of a building material, which is normally solid but which is flowable when heated. In one embodiment a support material is used to fill in portions of layers which are not to be solidified as part of the object to provide support to otherwise unsupported portions of other layers. Advantageously, the support material is also normally solid and flowable when heated, and has a lower melting point than the building material enabling the support material to later be removed without damaging the object. In an alternative embodiment this support material can be used to build a support such as a web support, or the like, for supporting an object surface from a second surface.

Abstract: An apparatus and a method for calibrating and normalizing a stereolithographic apparatus so that a reaction means directed by a positioning means supplied with positioning means information may be positioned accurately on a designated surface of a working medium. One or more sensors fixed in location with respect to the designated surface of the working medium are utilized to correlate positioning means information with specific locations on the designated surface of the working medium. Other locations intermediate the specific locations may then be determined by the technique of linear interpolation.

Abstract: A low cost multipurpose electronic ballast for ultraviolet transilluminators and crosslinkers for starting and operating four or more ultraviolet lamps simultaneously. The electronic ballast is designed to be capable of operating with input voltages ranging from 85 volts AC to 250 volts AC and input frequencies ranging from 40 Hertz to 400 Hertz. The output to the lamps comes from a group of capacitors which control the current to the lamps. Because the output comes from capacitive ballasts in parallel, alternate sets of capacitors can be switched to alternate sets of lamps allowing the central ballast control to be used with different sets of lamps. By placing another set of capacitors in parallel with the existing output capacitors and making a momentary connection, a momentary power boost can be achieved. This feature also allows a variable intensity control comprised of a number of different size capacitors in series with the parallel group to vary the total current to all the lamps.

Abstract: Improved apparatus and methods for forming a layer of material over a surface of a previously-formed cross-section of a three-dimensional object in anticipation of forming a next cross-section of the object out of the layer. A volume of material, including at least some excess material, is placed over the surface, and the excess material is swept off by placing the excess material in the predetermined path of a sweeping member, the path being substantially in a plane spaced from a working surface of material. The member may be directed to sweep the excess material away through a successive number of sweeps, which may vary for each cross-section, at least a velocity which may vary for each sweep. Additionally, the clearance between the member and the surface of the previous cross-section may vary for each sweep. A "winged" member is also provided, comprising two legs extending from a base, and a "Trident" embodiment is also provided, comprising three legs extending from a base.

Abstract: 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.

Abstract: Apparatus for and related methods of forming three-dimensional objects out of a building material, which is normally solid but which is flowable when heated. In one embodiment a support material is used to fill in portions of layers which are not to be solidified as part of the object to provide support to otherwise unsupported portions of other layers. Advantageously, the support material is also normally solid and flowable when heated, and has a lower melting point than the building material enabling the support material to later be removed without damaging the object. In an alternative embodiment this support material can be used to build a support such as a web support or the like for supporting an object surface from a second surface.

Abstract: An improved stereolithography system for generating a three-dimensional object by creating a cross-sectional pattern of the object to be formed at a selected surface of a fluid medium capable of altering its physical state in response to appropriate synergistic stimulation by impinging radiation, particle bombardment or chemical reaction, information defining the object being specially processed to reduce curl and distortion, and increase resolution, strength, accuracy, speed and economy of reproduction even for rather difficult object shapes, the successive adjacent laminae, representing corresponding successive adjacent cross-sections of the object, being automatically formed and integrated together to provide a step-wise laminar buildup of the desired object, whereby a three-dimensional object is formed and drawn from a substantially planar surface of the fluid medium during the forming process.

Abstract: An apparatus and a method for calibrating and normalizing a stereolithographic apparatus so that a reaction means directed by a positioning means supplied with positioning means information may be positioned accurately on a designated surface of a working medium. One or more sensors fixed in location with respect to the designated surface of the working medium are utilized to correlate positioning means information with specific locations on the designated surface of the working medium. Other locations intermediate the specific locations may then be determined by the technique of linear interpolation.

Abstract: An active mirror laser amplifier is described having a slab of Nd:glass which is optically pumped through the back face while the laser beam enters the slab through the front face and is reflected by a coating on the back face which reflects the laser beam while transmitting the pumping radiation. The laser beam is amplified as it moves toward the back face and after reflection from the back face as it propagates out and is emitted from the front face. The front face has an anti-reflection coating for the laser beam which coating reflects the pumping radiation. The storage efficiency of the laser is thereby increased and the temperature gradients in the slab are reduced (viz., the temperature profile is smoothed such that distortion of the slab is reduced and high power operation at high repetition rates of the laser pulse is obtainable).