Abstract: A method and apparatus for making an object by stereolithography from layers of a medium solidifiable upon exposure to synergistic stimulation by selecting an area element of a first layer of medium. The depth of the medium within the object underlying the area element is determined and compared to the depth to the minimum solidification depth of the medium. The area element is exposed to solidifying synergistic stimulation only if the depth of the medium equals or exceeds the minimum solidification depth. A next layer is created over the first layer without exposing the first layer to solidifying synergistic stimulation, if the depth is less than the minimum solidification depth. The layers may have a thickness selected such that the minimum solidification depth is a integer multiple of the layer thickness.

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: A stereolithography system employing a more powerful laser and faster dynamic mirrors to speed up part building without sacrificing accuracy is described, especially large or complex parts. A controllable shutter is placed in the beam path of the laser to selectably block the passage of the beam and prevent unwanted solidification. A suitable servo controlled feedback loop is provided to accurately position the mirrors at the higher velocity.Also described is a means to reduce data flow by distributing tasks in a multiple processor environment, and to improve user interaction by the use of a spreadsheet model. These also improve the speed of part building, especially for large or complex parts.

Abstract: An improved stereolithographic apparatus (SLA) and an improved method for generating a part from curable material. The invention utilizes control and/or knowledge of depths of penetration of actinic radiation into a vat of photopolymer to determine and/or control and/or produce desirable characteristics associated with the creation of parts. From a predictive point of view, these desirable characteristics may include determination of cure depth from a given exposure, determination cure width, determination of required minimum surface angle (MSA), determination of optimum skin fill spacing, the strength of cross sections of partially polymerized material, amount of curl type distortion, and necessary overcure to attain adhesion between layers, etc. These determinations can lead to the use of particular building techniques to insure adequate part formation.

Abstract: An improved method for stereolithographically making an object by alternating the order in which similar sets of vectors are exposed over two or more layers. In another method, a pattern of tightly packed hexagonal tiles are drawn. Each tile is isolated from its neighboring tiles by specifying breaks of unexposed material between the tiles. Using an interrupted scan method, vectors are drawn with periodic breaks along their lengths. In another method, modulator and scanning techniques are used to reduce exposure problems associated with the acceleration and deceleration of the scanning system when jumping between vectors or changing scanning directions.

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: A system for generating three-dimensional objects 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, 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 improved stereolithography system and method for curing a stereolithography-produced part, including at least some material that is no more than partially transformed, by exposing the part to off-peak absorptive wavelengths of synergistic stimulation to achieve a more uniform cure.

Abstract: An improved stereolithographic apparatus and method is described. In one embodiment, the improvement includes immersing at least a portion of a part in a volume of a liquid solvent in a vapor degreaser while subjecting the portion to ultrasonic agitation to substantially remove excess resin. Several examples of solvents are provided, including ethanol, and Freon TMS. In a second embodiment, the improvement includes building the part on a layer of liquid resin supported by a volume of a dense, immiscible, and UV transparent intermediate liquid, and integratably immersing at least a portion of the built part in the intermediate liquid, and then either subjecting the immersed portion to ultrasonic agitation to substantially remove excess resin, or subjecting the immersed portion to UV light. Several examples of intermediate liquids are provided, including perfluorinated fluids, such as Fluorinert FC-40, and water-based salt solutions, such as solutions of magnesium sulfate or sodium chloride in water.

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: A stereolithographic device and method including a process module, a control module and a service module. A laser is employed through a dynamic mirror system controlled by the control module to generate solidified cross sections of a selected part design on the surface of a photocurable polymer liquid. By lowering cured cross sections into the vat, additional cross sections can be perpared and joined therewith to define a prototype product. A stationary mirror in the beam path between the dynamic mirror system and the photocurable polymer is employed to make the system more compact and practical. A calibration and normalization process provides correction to distortions and misalignment of the stationary mirror.

Abstract: A stereolithographic method for constructing an object from a medium capable of solidification upon exposure to synergistic stimulation (e.g. a laser beam). Stacked layers of solidified medium are constructed by exposing the medium to synergistic stimulation in magnitude and pre-selected pattern, such that each layer is formed with external boundaries and up and down facing surfaces as necessary. At least a portion of a layer which is neither upfacing nor downfacing is also skinned, e.g., provided with a continuous skin formed by overlapping skin vectors or traces of the laser beam. Alternatively, all intermediate or internal cross-sectional layers are provided with skin and cross-hatch. Upfacing and downfacing features, and intermediate layers may be provided with a skin created by scanning in a first pass using non-consecutive skin vectors followed by scanning in at least one additional pass that completes the exposing process by filling in between the originally drawn vectors.

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 improved sterolithography system for generating a three-dimensional object from object defining information, the information defining the object being structurally specified to reduce curl, stress and distortion in the ultimately formed object is described. A stereolithographic distortion known as curl is reduced by the system, and several techniques to eliminate or reduce curl are utilized by the system, including dashed line, bent line, secondary structure, rivets, and multi-pass techniques.

Abstract: Disclosed is a system for fabricating an object by selective curing of successive films of curable resin formed separately from the object being formed. In a first preferred embodiment, a thin film is formed and selectively cured and stripped to form a layer of an object of predetermined pattern. In a second preferred embodiment, a carousel of funnels carries out parallel film formation and curing. A third preferred embodiment is disclosed having rotating carriers to achieve parallel film formation and curing. A fourth preferred embodiment is disclosed for forming very small objects of successive thin films.

Abstract: An apparatus and a method for profiling the intensity of a beam and thus measuring the overall intensity and power of a beam are disclosed that have particular use in stereolithography. A beam sensor comprising a pinhole in a plate and a photodetector behind the pinhole measures the intensity of portions of a beam as the beam is moved over the beam sensor. Software associated with the sensors in a computer controls the scanning mechanism for the beam so that the beam is shifted to find the pinhole and move across it in order to develope the intensity profile. The invention can be used to detect drift in the scanning mechanism, determine the focus of the beam, and predict the depth and width of photopolymer cured by the beam.

Abstract: An apparatus and a method for correcting for drift in production of objects by stereolithography is disclosed. A beam sensor comprising a pinhole in a plate and a photodector behind the pinhole is used to obtain the apparent position of the beam at calibration time and subsequently. A comparison between the prior and present apparent position of the sensor is made in order to determine a drift error correction term to be used to compensate for drift and thereby improve the accuracy and pointing repeatability of the scanning mechanism.

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, stress, birdnesting and other distortions, 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 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 tailored to provide built-in supports for the object, reduce curl and distortion, and increase resolution, strength, accuracy, speed and economy of reproduction, 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 improved sterolithography 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 bonbardment 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, and further including post processing wheren the object is subjected to additional UV curing while the object is