Abstract: Methods and apparatus for forming three-dimensional objects from a medium solidifiable when subjected to a beam of pulsed radiation wherein the pulses of radiation are made to occur when the beam is directed to desired pulsing locations on a target surface of the medium. Preferred embodiments of the instant invention include a pulsed laser assembly, including a laser and a pulse generation circuit, a control computer, a plurality of mirrors and mirror encoders. The computer controls the movement of the mirrors which guide the laser beam across the surface of the solidifiable medium. The pulsing of the laser beam is correlated to the position of the mirrors and thus, is not dependent upon time. Pulsing linked to position of beam placement allows controlled and repeatable use of a pulsed beam for the formation of objects.

Abstract: A variety of support structures and build styles for use in Rapid Prototyping and Manufacturing systems are described wherein particular emphasis is given to Thermal Stereolithography, Fused Deposition Modeling, and Selective Deposition Modeling systems, and wherein a 3D modeling system is presented which uses multijet dispensing and a single material for both object and support formation.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for making high resolution objects utilizing low resolution materials which are limited by their inability to reliably form coatings of a desired thickness. The formation of coatings of such materials is limited to a Minimum Recoating Depth (MRD), when formed over entirely solidified laminae, which is thicker than the desired layer thickness or object resolution. Data manipulation techniques result in layers of material (and laminae) of the object being categorized as non-consecutive primary layers (laminae) and secondary layers (laminae) positioned intermediate to the primary layers (laminae).

Abstract: Embodiments of the instant invention are directed to laser exposure system that employs a pulsed solid state laser to provide a reactive response wavelength and a pulse repetition rate specifically optimized for application to solidification of a liquid photopolymer in a stereolithographic process. The solid state laser employs two second harmonic crystals for generating an emission wavelength at about 320-345 nm and a pulse repetition rate, wherein the pulse repetition rate is selected such that a pulse separation at the target surface results which is less than a diameter of the beam when the beam is being scanned at a desired velocity and an average exposure deposited by the beam is equal to a desired amount.

Abstract: A method, system and apparatus for variably controlling the temperature in a selective deposition modeling environment. The temperature of the formed portion of the three-dimensional object is detected. A gas is forced onto a surface of the formed portion of the three-dimensional object. The forced gas has a characteristic, such as temperature and quantity, that is variably controlled based on the detected temperature of the formed portion of the three-dimensional object.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for making three-dimensional objects with simplified correlation of building parameters with object data. Object data is preferably correlated to (1) object build parameters that are used in solidifying object portions of layers of the material, (2) recoating parameters that are used in forming layers of material that include object data, (3) support build parameters that are used in solidifying support portions of layers of the material, (4) recoating parameters that are used in forming layers of material that include support data but no object data, and (5) parameters for use in generating a support structure that will be used to support the object during its formation. A style file is identified with each set of parameters. An algorithm (i.e. style wizard) is used to select among a plurality of styles of each type.

Abstract: A solid-state laser includes a high-absorption coefficient solid-state gain medium such as Nd:YVO.sub.4 that is side pumped with a semiconductor laser diode array. The resonant cavity of the solid-state laser is positioned so that the TEM.sub.00 mode is spaced from the face of the laser through which the laser is pumped by a distance sufficient to reduce diffraction losses but sufficiently near to allow coupling of pump light into the gain mode. The gain medium, the doping level of the gain medium, and the operating temperature of the pump laser are selected to efficiently couple pump light into the gain mode. The pump laser is positioned to side pump the gain medium without collimating or focusing optics between the pump laser and the face of the gain medium. A gap between the pump laser and the gain medium is empirically selected to match the angular extent of the pump laser output light to the height of the gain mode at the position of the gain mode fixed to optimize coupling and diffraction losses.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for making three-dimensional objects with enhanced control of the temperature of the build environment. A modulated control signal is supplied to a heating element based on a difference between a desired build temperature and a detected temperature. The modulated signal result in the heater supplying, on average, more energy to the build chamber when the temperature difference is large and supplying, on average, less energy to the build chamber when the difference is small. The detection of the build chamber temperature may occur at one or more locations. If multiple locations are used, the detected temperatures may be averaged, or otherwise combined, to derive a single difference value that will be used to control the heater.

Abstract: A method is disclosed for making a molded refractory article comprising the steps of providing a mold including a molding pattern, the mold and molding pattern defining a mold cavity; filling the mold cavity around the molding pattern with a mixture comprising refractory particles and a heat fugitive binder; inserting a plurality of elements of relatively high melting point material into the mixture to displace a portion of the mixture; curing the mixture; separating the mold and molding pattern from the cured mixture; and sintering the combination of the cured mixture and mixture displacing elements to provide a reinforced molded refractory article. The mixture displacing elements preferably comprise a plurality of parallel tool steel rods. Also disclosed is an apparatus for molding the aforedescribed reinforced refractory article.

Abstract: Techniques for printing raster lines in a selective deposition modeling (SDM) system. Raster lines may be printed using different numbers of jets in each group in different passes. Moreover, full and partial head randomization is available. Selected raster lines are printed in one direction, although the print head prints in two directions. Furthermore, raster lines printing may be interlaced, and deposition order may be changed between layers.

Abstract: Phase change compositions that are solid at ambient temperature and liquid at an elevated temperature above ambient temperature are disclosed for advantageous use in selective deposition modeling methods for building three-dimensional objects. A phase change composition according to the disclosed invention is a semi-crystalline component mixture having a freezing point of at least about 68.degree. C., a melting point of at least about 88.degree. C. and a viscosity of about 13 centipoise at 135.degree. C. The composition includes a plurality of waxes having a broad melting point range and molecular weight range. Three-dimensional objects having minimal curl, delamination and stress cracks can be produced at a faster rate than heretofore known by using selective deposition modeling techniques employing the disclosed compositions.

Abstract: A novel thermopolymer material adapted for use in thermal stereolithography. More particularly, a thermopolymer material comprising a mixture of: a low shrinkage polymer resin; a low viscosity material such as paraffin wax; at least one microcrystalline wax; a toughening polymer; a plasticizer. Alternative embodiments further include components to improve the materials ability to transfer heat and to improve strength. The subject material, together with the described process greatly reduce part building distortions while retaining desirable toughness, strength and jetting properties.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for producing three-dimensional objects by selectively subjecting a liquid or other fluid-like material to a beam of prescribed stimulation. In a preferred embodiment a source of prescribed stimulation is controlled to reduce or inhibit the production of the prescribed stimulation during at least some periods when the prescribed stimulation is not needed to expose the material. In another preferred embodiment, the source of stimulation is controlled to vary the quantity of prescribed stimulation that is produced and allowed to reach the material. In an additional preferred embodiment control of laser output occurs based on a combination of supplying a regulated amount of voltage to an AOM in conjunction with temporary sensing of laser power and a known desired power to attain.

Abstract: A solubilizing agent and a compound made by reacting selected nucleophiles, including fatty acid reactants and amines with an isocyanate are disclosed. The addition of the isocyanate and the different nucleophiles will create a di-urethane tetra-amide solubilizing agent product. The polyamide-solubilizing agent is useful as an ingredient in a phase change solid imaging material and as carrier compositions used to make phase change ink jet inks.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for producing three-dimensional objects by selectively subjecting a liquid or other fluid-like material to a beam of prescribed stimulation. In a preferred embodiment a source of prescribed stimulation is controlled to reduce or inhibit the production of the prescribed stimulation during at least some periods when the prescribed stimulation is not needed to expose the material. In another preferred embodiment, the source of stimulation is controlled to vary the quantity of prescribed stimulation that is produced and allowed to reach the material. In an additional preferred embodiment, control of laser output occurs based on a combination of supplying a regulated amount of voltage to an AOM in conjunction with temporary sensing of laser power and a known desired power to attain.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for producing three-dimensional objects by selectively subjecting a liquid or other fluid-like material to a beam of prescribed stimulation. In a preferred embodiment a source of prescribed stimulation is controlled to reduce or inhibit the production of the prescribed stimulation during at least some periods when the prescribed stimulation is not needed to expose the material. In another preferred embodiment, the source of stimulation is controlled to vary the quantity of prescribed stimulation that is produced and allowed to reach the material. In an additional preferred embodiment control of laser output occurs based on a combination of supplying a regulated amount of voltage to an AOM in conjunction with temporary sensing of laser power and a known desired power to attain.

Abstract: A phase change ink carrier composition comprising at least one anhydride/alcohol inclusive reaction product.

Abstract: A rapid prototyping and manufacturing (e.g. stereolithography) method and apparatus for making three-dimensional objects with enhanced control of coating parameters used when forming layers of liquid or other fluid-like material in preparation for forming laminae of the object. The each lamina of the object is treated as either a primary laminae or secondary laminae. Only minority portions of the secondary layers are solidified when their associated layers are formed. Primary laminae are solidified in majority portions, along with previously unsolidified portions of secondary lamina, when their associated layers are formed. Recoating parameters are supplied for groups of primary layers and secondary layers such that coating formation may be controlled differently for primary layers and for secondary layers. Coating control for secondary layers may be based on the position of individual secondary layers, or sets of secondary layers, relative to the primary layers.

Abstract: An improved method for providing a continuous supply of liquid ink to an ink jet print head is provided. The method maintains an estimate in a memory source of the amount of liquid in a reservoir that is available to the print head. The estimate is periodically updated by information received from an ink sensor in the reservoir. By comparing the estimate to a plurality of ranges, the method determines whether additional ink may be added to the reservoir.

Abstract: An ink jet printer includes an image transfer drum and a print head for ejecting drops of ink toward the image transfer drum as the drum rotates relative to the print head undergo. A control mechanism controls operation of the print head relative to rotation of the drum in response to a dot clock signal. The control mechanism includes a position encoder which generates an encoder signal at a frequency dependent on rotation of the image transfer drum and a digital phase locked loop circuit which receives the encoder signal and generates the dot clock signal at a frequency equal to the frequency of the encoder signal multiplied by a rational number.