Abstract: A method of additive manufacturing of a three-dimensional object includes sequentially dispensing and solidifying a plurality of layers. The plurality of layers may be formed with a plurality of different colored model materials, a flexible material arranged in a configured pattern to form a sacrificial structure at least partially encompassing the object, and a soft material. The soft material is arranged in a configured pattern to provide separation between the model material and the sacrificial structure. The plurality of different colored model materials is arranged in a configured pattern corresponding to the shape and color definition of the object.

Abstract: An inkjet printing method and inkjet compositions are disclosed. The method includes selectively depositing by inkjet printing, layer by layer, a first composition and a second composition onto a receiving media from different dispensers to form polymerizable deposited layers. The first composition includes one or more free-radical polymerizable compounds and a cationic photoinitiator and is devoid of compounds able to undergo cationic photopolymerization within the first composition. The second composition includes one or more cationic polymerizable compounds and is devoid of cationic photoinitiators. At least one of the compositions includes a radical photoinitiator. The method further includes exposing the deposited layers to actinic radiation to initiate polymerization of the free-radical polymerizable compounds and the cationic polymerizable compounds within the deposited layers.

Abstract: A method of additive manufacturing of a three-dimensional object includes sequentially dispensing and solidifying a plurality of layers. The plurality of layers may be formed with a plurality of different colored model materials, a flexible material arranged in a configured pattern to form a sacrificial structure at least partially encompassing the object, and a soft material. The soft material is arranged in a configured pattern to provide separation between the model material and the sacrificial structure. The plurality of different colored model materials is arranged in a configured pattern corresponding to the shape and color definition of the object.

Abstract: A method of three-dimensional fabrication of an object is disclosed. The method comprises: forming a plurality of layers in a configured pattern corresponding to the shape of the three-dimensional object, at least one layer of the plurality of layers being formed at a predetermined and different thickness selected so as to compensate for post-formation shrinkage of the layer along a vertical direction. In various exemplary embodiments of the invention spread of building material of one or more layers is diluted at least locally such as to maintain a predetermined thickness and a predetermined planar resolution for the layer.

Abstract: A method of additive manufacturing of a three-dimensional object is disclosed. The method comprises sequentially forming a plurality of layers each patterned according to the shape of a cross section of the object. In some embodiments, the formation of at least one of the layers comprises performing a raster scan to dispense at least a first building material composition, and a vector scan to dispense at least a second building material composition. The vector scan is optionally along a path selected to form at least one structure selected from the group consisting of (i) an elongated structure, (ii) a boundary structure at least partially surrounding an area filled with the first building material, and (iii) an inter-layer connecting structure.

Abstract: A method of three-dimensional fabrication of an object is disclosed. The method comprises: forming a plurality of layers in a configured pattern corresponding to the shape of the three-dimensional object, at least one layer of the plurality of layers being formed at a predetermined and different thickness selected so as to compensate for post-formation shrinkage of the layer along a vertical direction. In various exemplary embodiments of the invention spread of building material of one or more layers is diluted at least locally such as to maintain a predetermined thickness and a predetermined planar resolution for the layer.

Abstract: A method of printing a three-dimensional (3D) object and a support construction for the 3D object includes depositing a model material, layer-by-layer, on a fabrication platform, to print a first portion of the 3D object, and depositing a support material, layer-by-layer on the fabrication platform, to print the support construction, wherein, in a predetermined number of the deposited layers, the model material and the support material are deposited such that a gap is formed between a surface of the first portion of the 3D object and a surface of the support construction.

Abstract: A method of additive manufacturing of a three-dimensional object. The method comprises: sequentially dispensing and solidifying a plurality of layers comprising (i) a stack of model layers arranged in a configured pattern corresponding to the shape of the object and being made of a modeling material, (ii) a sacrificial structure having a stack of sacrificial layers made of an elastomeric material, and (iii) a stack of intermediate layers made of a support material having an elastic modulus less than the elastomeric material and being between the stack of model layers and the sacrificial structure; and applying a peeling force to the sacrificial structure to remove the sacrificial structure, and to expose the stack of model layers and/or the stack of intermediate layers beneath the sacrificial structure.

Abstract: A method of additive manufacturing of a three-dimensional object is disclosed. The method comprises sequentially forming a plurality of layers in a configured pattern corresponding to the shape of the object. Each layer is formed by dispensing at least one modeling material to form an uncured layer, and curing the uncured layer by radiation. In various exemplary embodiments of the invention the method comprises, for at least one layer, forming a stack of sacrificial radiation-protective layers to cover an exposed portion of the layer, such that an upper layer of the stack remains exposed during formation of any subsequent layer of the plurality of layers.

Abstract: A method of additive manufacturing a three-dimensional object by layerwise deposition of a building material with an inkjet printing system comprising a print head and a building tray, comprises calculating a weighting value for each nozzle, then for each layer obtaining a 2-D map of the layer, comprising active pixels at building material dispensing positions; obtaining a Data Correction Filter (DCF) including a height map of the previous layer, comparing the data of the 2D map to the data of the DCF at each position and determining if the nozzle at that position should dispense, then printing the layer, updating the weighting values and adjusting the position of the print head vis a vis the printing tray. The above is repeated until the three-dimensional object is printed.

Abstract: A method of additive manufacturing of a three-dimensional object. The method comprises: sequentially dispensing and solidifying a plurality of layers comprising (i) a stack of model layers arranged in a configured pattern corresponding to the shape of the object and being made of a modeling material, (ii) a sacrificial structure having a stack of sacrificial layers made of an elastomeric material, and (iii) a stack of intermediate layers made of a support material having an elastic modulus less than the elastomeric material and being between the stack of model layers and the sacrificial structure; and applying a peeling force to the sacrificial structure (e.g., in dry environment) to remove the sacrificial structure, and to expose the stack of model layers and/or the stack of intermediate layers beneath the sacrificial structure.

Abstract: A method of additive manufacturing a three-dimensional object by layerwise deposition of a building material with an inkjet printing system comprising a print head and a building tray, comprises calculating a weighting value for each nozzle, then for each layer obtaining a 2-D map of the layer, comprising active pixels at building material dispensing positions; obtaining a Data Correction Filter (DCF) including a height map of the previous layer, comparing the data of the 2D map to the data of the DCF at each position and determining if the nozzle at that position should dispense, then printing the layer, updating the weighting values and adjusting the position of the print head vis a vis the printing tray. The above is repeated until the three-dimensional object is printed.

Abstract: A method for preventing detachment of a three-dimensional object from a printing tray of a printing apparatus is disclosed. The method includes printing a carpet of building material below and around the base of a three-dimensional object to be printed; and printing said three-dimensional object. The portions of the carpet that protrude out of the boundaries of the base of the three-dimensional object are coated with one or more layers of support material to help keep the carpet flexible and adhesive in texture.

Abstract: A method of additive manufacturing of a three-dimensional object is disclosed. The method comprises sequentially forming a plurality of layers each patterned according to the shape of a cross section of the object. In some embodiments, the formation of at least one of the layers comprises performing a raster scan to dispense at least a first building material composition, and a vector scan to dispense at least a second building material composition. The vector scan is optionally along a path selected to form at least one structure selected from the group consisting of (i) an elongated structure, (ii) a boundary structure at least partially surrounding an area filled with the first building material, and (iii) an inter-layer connecting structure.

Abstract: A method of layerwise solid freeform fabrication is disclosed. The method comprises, for each of at least a few of the layers, dispensing and hardening at least a first modeling material and a second modeling material to form a core region and one or more envelope regions at least partially surrounding the core region. In some embodiments, the ratio between the elastic moduli of adjacent regions, when hardened, is from about 1 to about 20.

Abstract: A method of additive manufacturing of a three-dimensional object is disclosed. The method comprises sequentially forming a plurality of layers each patterned according to the shape of a cross section of the object. In some embodiments, the formation of at least one of the layers comprises performing a raster scan to dispense at least a first building material composition, and a vector scan to dispense at least a second building material composition. The vector scan is optionally along a path selected to form at least one structure selected from the group consisting of (i) an elongated structure, (ii) a boundary structure at least partially surrounding an area filled with the first building material, and (iii) an inter-layer connecting structure.

Abstract: A system and methods for solid freeform fabrication of an object is disclosed. The system comprises a solid freeform fabrication apparatus having a plurality of dispensing heads, a building material supply apparatus configured to supply a plurality of building materials to the fabrication apparatus, and a control unit configured for controlling the fabrication apparatus and the supply apparatus based on an operation mode selected from a plurality of predetermined operation modes.

Abstract: A method of layerwise solid freeform fabrication is disclosed. The method comprises, for each of at least a few of the layers, dispensing and hardening at least a first modeling material and a second modeling material to form a core region and one or more envelope regions at least partially surrounding the core region. In some embodiments, the ratio between the elastic moduli of adjacent regions, when hardened, is from about 1 to about 20.

Abstract: 3D (three-dimensional) ink-jet printing includes techniques for evaporating a carrier liquid during printing while at least a portion of dispersant remains in the printed layer; evaporating dispersant in a first layer prior to sintering the first layer and/or prior to printing a second layer; leveling an upper-layer of a printed object using a horizontal roller; and printing layers of an object, each layer with both object and support portions, resulting in an object with support, in particular, support for negative angles and molds.

Abstract: A method suitable for solid freeform fabrication is disclosed. The method comprises mixing respective amounts of a plurality of materials such as to provide a building material characterized by at least one attribute, and using the building material for fabricating a three-dimensional object.