This invention relates to printable high strength/toughness polymerizable material systems for making dental products such as artificial teeth, dentures, splints, veneers, inlays, onlays, orthodontic appliances, aligners, copings, frame patterns, crowns and bridges and the like. A DLP, stereolithography, modified or their modification and combination based printer is used to cure polymerizable material in several different methods of this invention to build-up the object. The resulting three-dimensional object has good dimensional stability.

A method of forming a three-dimensional object is carried out by: providing a carrier and an optically transparent member having a build surface, the carrier and the build surface defining a build region therebetween; filling the build region with a polymerizable liquid; irradiating the build region through the optically transparent member to form a solid polymer from the polymerizable liquid while concurrently advancing the carrier away from the build surface to form the three-dimensional object from the solid polymer, while also concurrently: (i) continuously maintaining a dead zone of polymerizable liquid in contact with the build surface by electrochemically generating a polymerization inhibitor therein from a precursor of the polymerization inhibitor, and (ii) continuously maintaining a gradient of polymerization zone (e.g., an active surface) between the dead zone and the solid polymer and in contact with each thereof, the gradient of polymerization zone comprising the polymerizable liquid in partially cured form. Apparatus for carrying out the method is also described.

A disclosed system includes an additive manufacturing printer that performs a layer by layer three-dimensional printing process generating a casting mold based on a three-dimensional numerical specification. The numerical specification is based on a desired casting shape, including internal features such as hollow areas formed by cores, and is further based on a thermo-mechanical model of a casting process. The numerical specification describes variations in material and geometric properties of one or more layers of the casting mold corresponding to variations in the thermal and mechanical properties of the casting processes, as predicted by the thermo-mechanical model. The system may vary the thickness of features of the casting mold, based on predicted cooling rates, to reduce cooling non-uniformities and to provide for controlled, predictable cooling of the casting. The system may further generate trusses and heat sinks in the mold to respectively strengthen and weaken various features of the mold.

An additive manufacturing apparatus includes a table, an ejecting unit that faces the table and ejects photocurable droplets toward the table, a light-applying unit that applies light to and cures the droplets on the table, a moving unit that moves the table back and forth along with the light-applying unit and relative to the ejecting unit, and a controller that controls the ejecting unit, the light-applying unit, and the moving unit such that the ejecting unit ejects droplets toward the table while the table is moved relative to the ejecting unit; the light-applying unit applies, when a direction of relative movement of the table is changed, light to the droplets that have moved together with the table out of an area where the table faces the ejecting unit; and a three-dimensional object is formed as a stack of layers composed of the droplets that have been cured.

The inventive subject matter provides an apparatus for reproducibly fabricating hydrogel-based organ and tumor models inside multi-well plates. For example, tumor models made using the inventive apparatus can be used for studying the progression of cancer, cancer diagnostics, and therapeutic screening. A mold controls the thickness of each hydrogel layer. A photomask controls the size and shape of each hydrogel layer, allowing the hydrogel diameter to be smaller than the diameter of each well so that liquid media can be exchanged around both the sides and top of the hydrogels. A holder aligns the photomask with the multi-well plate, and polymerization is initiated by a light source.

A method for additive manufacturing includes: at a build tray arranged over a build window and containing a resin reservoir of a resin, heating the resin reservoir toward a target bulk resin temperature less than a heat deflection temperature of the resin in a photocured state; at a resin interface between a surface of the build window and the resin reservoir, heating an interface layer of the resin reservoir toward a target reaction temperature; and, in response to the resin reservoir exhibiting a first temperature proximal the target bulk resin temperature and to the interface layer exhibiting a second temperature proximal the target reaction temperature: at the resin interface, selectively photocuring a first volume of the resin to form a first layer of a build adhered to a build platform; and retracting the build platform away from the build window.

A method for additive manufacturing includes: at a build tray arranged over a build window and containing a resin reservoir of a resin, heating the resin reservoir toward a target bulk resin temperature less than a heat deflection temperature of the resin in a photocured state; at a resin interface between a surface of the build window and the resin reservoir, heating an interface layer of the resin reservoir toward a target reaction temperature; and, in response to the resin reservoir exhibiting a first temperature proximal the target bulk resin temperature and to the interface layer exhibiting a second temperature proximal the target reaction temperature: at the resin interface, selectively photocuring a first volume of the resin to form a first layer of a build adhered to a build platform; and retracting the build platform away from the build window.

A sliding window is used in a projection-based stereolithographic process to more quickly deliver uncured resin after each curing pass. The sliding window may be configured in different patterns, and includes features for delivering resin and exposing resin to curing radiation. The window screen divides the stereolithographic building area divided into two portions, a light exposure portion for resin curing and a liquid resin refilling portion. The light exposure portion is used to selectively solidify liquid resin, while the liquid resin refilling portion is used to quickly refill liquid resin in order to build additional layers. During the layer fabrication process, a mask image is projected to the tank; however, the projection light only passes through the light exposure portion of the window screen.

A sliding window is used in a projection-based stereolithographic process to more quickly deliver uncured resin after each curing pass. The sliding window may be configured in different patterns, and includes features for delivering resin and exposing resin to curing radiation. The window screen divides the stereolithographic building area divided into two portions, a light exposure portion for resin curing and a liquid resin refilling portion. The light exposure portion is used to selectively solidify liquid resin, while the liquid resin refilling portion is used to quickly refill liquid resin in order to build additional layers. During the layer fabrication process, a mask image is projected to the tank; however, the projection light only passes through the light exposure portion of the window screen.

An additive manufacturing machine includes: a resin support which has at least a portion which is transparent, wherein the resin support defines a build surface; a material depositor operable to deposit a resin which is radiant-energy-curable onto the build surface; at least two build stations, each build station including: a stage positioned adjacent the build zone and configured to hold a stacked arrangement of one or more cured layers of the resin; one or more actuators operable to manipulate a relative position of the stage and the build surface; and at least one radiant energy apparatus positioned opposite to the stage, and operable to generate and project radiant energy in a predetermined pattern.