Abstract: A stereolithography apparatus having a resin vat with resupply containers in one-way flow communication and a leveling container in two-way flow communication, an automatic offload cart to remove and replace build support platforms, an elevator assembly for supporting and releasably retaining a build platform removably attached to the stereolithography apparatus frame such that elevator forks supporting the build platform can be released into the vat and removed from the stereolithography apparatus with the vat, and a recoater assembly and recoater blade for mapping the resin surface in the vat and applying a fresh coating of resin to a cross-section being built in the vat.

Abstract: The invention relates to a method producing parts using laser sintering wherein a fusible powder is exposed to a plurality of laser scans at controlled energy levels and for time periods to melt and densify the powder and in the substantial absence of particle bonding outside the fusion boundary. Strength is improved up to 100% compared to previous methods. An example includes a relatively high energy initial scan to melt the powder followed by lower energy scans controlled to densify the melt and separated in time to dissipate heat to the surrounding part cake. The rate and extent to which the powder particles are fused together can be controlled so that each successive scan can be used to fuse the particles together in discreet incremental steps. As a result, the final dimensions of the part and its density and mechanical properties can be improved compared to conventional methods and part growth avoided.

Abstract: A stereolithography apparatus having a resin vat with resupply containers in one-way flow communication and a leveling container in two-way flow communication, an automatic offload cart to remove and replace build support platforms, an elevator assembly for supporting and releasably retaining a build platform removably attached to the stereolithography apparatus frame such that elevator forks supporting the build platform can be released into the vat and removed from the stereolithography apparatus with the vat, and a recoater assembly and recoater blade for mapping the resin surface in the vat and applying a fresh coating of resin to a cross-section being built in the vat.

Abstract: The invention is a method for controllably cooling at least a portion of a part-cake from a laser sintering system to minimize cool down time, maximize throughput, and minimize thermal gradients within the part-cake. The method generally comprises forming one or more thermal transfer channels within the part-cake. The thermal transfer channels can include ducts and cooling fins in the part-cake surrounding the formed part. The method can further comprise removing unfused powder from the ducts and introducing cooling media into the ducts. The invention also includes a part-cake having thermal transfer channels formed therein and a laser sintering apparatus comprising a part-cake containing cylinder having permanent fittings therein for receiving terminal portions of thermal transfer channels formed in the part-cake.

Abstract: Methods for generating supports (30) for parts (50) produced by solid freeform fabrication (“SFF”) are disclosed. The method includes defining a plurality of layers (L) that make up the part, and for each layer, determining those regions (R) that require support. The method also includes merging the regions for the different layers (L) into one or more common regions that require support, and providing at least one support for each of the one or more common regions. The result is that fewer supports are used as compared to conventional SFF fabrication methods.

Abstract: A solid imaging apparatus and method employing a radiation transparent build material carrier and a build material dispensing system that accurately controls the thickness of the transferred layer of solidifiable liquid build material to the radiation transparent build material carrier to achieve high resolution imaging in three-dimensional objects built using an electro-optical radiation source.

Abstract: A method and apparatus for pneumatic powder transfer from a powder supply container to applications such as laser sintering systems. The method and apparatus use both constant and cyclic flows of a pressurized gas to fluidize and convey powders without the need for any tilting unloading stands, vibration or other mechanical working of the powder.

Abstract: A convection cooling technique for selective deposition modeling utilizing a venturi duct to establish a low-pressure port for drawing a second flow of air into the duct. The second flow of air is drawn across a heat generating component in the selective deposition modeling apparatus. A low-pressure zone is established at the low-pressure port sufficient to meet the head loss that results when drawing the second flow across the heat generating component and into the venturi duct. A desired flow rate is achieved at a pressure drop that is greater than that possible by the direct use of a fan. The cooling system is well suited for use in providing steady state cooling of radiation exposure systems used in selective deposition modeling to initiate curing of the layers of dispensed material.

Abstract: Solid imaging apparatus and methods for use are disclosed that reduce the amount of uncured solid imaging build material remaining on a completed build object following the completion of the solid imaging build process. The amount of uncured build material is reduced through the use of either an uncoating web that removes excess build material from the build object during the course of the building process or an ink jet source of build material that uses only as much build material as is necessary for the fabrication of the build part. Also disclosed is an imager assembly for use with such a solid imaging apparatus that incorporates two or more individual imagers in an array and accounts for variations in the intensity and alignment of adjacent imagers. The apparatus can be modified for semi-continuous operation and for integrating into a manufacturing operation, if desired.

Abstract: A flash curing system for solid freeform fabrication which generates a plurality of radiation emitting pulses that forms a planar flash. The planar flash initiates curing of a curable material dispensed by a solid freeform fabrication apparatus. The radiation emitting pulses have a high peak power value that releases a sufficient quantity of free radicals from the photoinitiator to initiate curing and overcome the problem of oxygen inhibition. Substantially less power is consumed and less heat generated by the flash curing system compared to conventional continuous emission curing systems.

Abstract: A jettable non-curable support material composition useful for three-dimensional ink jet printing comprising at least one fatty alcohol and at least one abietic rosin ester alcohol, wherein the support material has a melting point between about 50° C. to about 65° C. and a freezing point between about 45° C. to about 55° C.

Abstract: A UV curable composition useful for three-dimensional inkjet printing comprising (i) at least one UV curable urethane (meth)acrylate resin; (ii) at least one wax; (iii) at least one (meth)acrylate diluent; (iv) at least one photoinitiator; and (v) at least one polymerization inhibitor; wherein the amount of wax (ii) is sufficient to phase change the UV curable composition after jetting.

Abstract: The invention is a rapid prototype apparatus having a removable build chamber and a plurality of alignments surfaces that can be used to properly align the build chamber with the process chamber with minimal adjustments by a user. In one embodiment, the apparatus comprises a process chamber attached to a support housing and a build chamber that is removably attached to the support housing. The build chamber may be inserted into the support housing and is moveable between a load position and a build position. The build chamber includes a moveable build platform and a plurality of alignment surfaces that are each adapted to releasably engage a corresponding surface on the support housing. As the build chamber moves into the build position, the alignment surfaces align the build platform the process chamber. As a result, the apparatus may be used to accurately align the build chamber with the process chamber.

Abstract: A radiation curable composition comprising: A) at least one urethane poly(meth) acrylate compound; B) at least one poly(meth)acrylate compound; C) at least one polyester poly(meth)acrylate compound; D) at least one silicone poly(meth)acrylate compound; E) at least one visible light range free radial photopolymerization initiator; and F) at least one UV light range free radical polymerization initiator.

Abstract: A laser scanning system in a rapid-protyping system is controlled during vector scanning by providing a commanded-position signal to each of first and second rotary motive devices to rotate respective mirrors of the scanning system, each mirror undergoing acceleration at the beginning of the vector, wherein the commanded-position signals are calculated based on physical mathematical modeling of the acceleration of the mirrors taking into account effects of inertia of the scanning system, and wherein actual positions of the mirrors are measured with fast-response devices and digital feedback control of the mirror positions is employed at a periodic rate sufficiently small to maintain a following error of the laser spot less than about 200 ?s at all times. A laser power control method employs a fast-response power meter for measuring laser power.

Abstract: A method and apparatus for pneumatic powder transfer from a powder supply container to applications such as laser sintering systems. The method and apparatus use both constant and cyclic flows of a pressurized gas to fluidize and convey powders without the need for any tilting unloading stands, vibration or other mechanical working of the powder.

Abstract: A method for removing supports from a three-dimensional objected formed by selective deposition modeling. The three-dimensional object is formed from a curable phase change material and the supports are formed from a non-curable phase change material. The curable phase change material contains between about 5% to about 25% of a non-reactive wax in order to achieve the desired phase change characteristics of the material. When removing the supports with heat, discoloration undesirably occurs in the three-dimensional object as the non-reactive wax migrates within the object. The method prevents wax migration by cooling the object slowly past the freezing point of the build material such that a temperature differential no greater than about 5° C. is present within the object. With the preferred build material having a freezing point of about 49.5° C., this is achieved by lowering the temperature between about 62° C. to about 52° C.