Abstract: Novel support material formulations, characterized as providing a cured support material with improved dissolution rate, while maintaining sufficient mechanical strength, are disclosed. The formulations comprise a water-miscible non-curable polymer, a first water-miscible, curable material and a second, water-miscible material that is selected capable of interfering with intermolecular interactions between polymeric chains formed upon exposing the first water-miscible material to curing energy. Methods of fabricating a three-dimensional object, and a three-dimensional object fabricated thereby are also disclosed.

Abstract: A method of three-dimensional printing, comprises: operating a printing head having a nozzle array to dispense a building material formulation, wherein the printing head is directly connected to a cartridge containing the building material formulation, and wherein the printing head comprises a channel conveying a building material formulation received from the cartridge to the nozzle array; discarding the building material formulation from the channel; and connecting a cartridge containing a building material formulation that is different from the discarded building material formulation to the channel.

Abstract: A method of additive manufacturing, comprises: dispensing from an array of nozzles an amount of building material formulation to form a layer in a configured pattern corresponding to a shape of a slice of an object, and hardening the layer. Based on the amount and a geometrical characteristic of the slice, a thermal mass of the layer is calculated. A cooling system is controlled in a closed loop control responsively to the calculated thermal mass.

Abstract: A formulation usable as a modeling material formulation in additive manufacturing of a three-dimensional object and additive manufacturing methods utilizing same are provided. The formulation comprises one or more curable materials; and a radiopaque material, and features, when hardened, a CT number of at least 100 HU at 70 kV. Objects made by the additive manufacturing method utilizing the formulation are usable as radiological phantoms.

Abstract: A printing head for inkjet printing comprises: a manifold having a channel for holding material formulation therein; and an array of controllable nozzles fluidly connected to the channel for dispensing the material formulation by inkjet technology. In an embodiment, the array of nozzles is characterized by a pitch that varies along the array. In an embodiment, the nozzles are arranged over a curved line engaging a horizontal plane.

Abstract: Methods and systems (100) of printing a 3D object (101) comprising: depositing material, layer by layer, via printing heads (72) comprising one or more nozzle arrays; and activating each of said printing heads (72) to dispense a building material (50) at least once within a specified period of time during printing.

Abstract: A method of printing comprises: detecting a defective nozzle in a first array of nozzles; disabling a nozzle in a second array of nozzles; dispensing a first material formulation from nozzles of the first array, other than the defective nozzle; and dispensing a second material formulation from nozzles of the second array, other than the disabled nozzle.

Abstract: Methods, systems and formulations of building a three-dimensional object with a glossy surface, the method may include: selectively depositing a first material in a plurality of layers to form a body region of the three-dimensional object, wherein said first material comprises a multifunctional acrylic monomer; selectively depositing a second material in a plurality of layers to form a support region, wherein said second material comprises a monofunctional hydrophilic acrylic monomer and does not comprise a multifunctional acrylic monomer; curing each of the deposited layers, wherein in at least one of the deposited layers the first material and the second material mix to form an intermediate region at their mutual interface; dissolving the support region in an aqueous solution; and drying the body region and the intermediate region, whereby the dried intermediate region provides a glossy surface on the body region of said three-dimensional object.

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 to define construction of a green compact with at least one object embedded therein is disclosed. The method includes receiving three-dimensional data defining the at least one object and identifying a planar surface in the at least one object based on the three-dimensional data. Orientation of the at least one object is defined so that the planar surface extends at least partially over a Z height of the green compact. A mask pattern is defined per layer to form the at least one object in the defined orientation by an additive manufacturing process with powder material.

Abstract: Formulation systems usable for fabricating a three-dimensional object made of a polyamide-containing material, by three-dimensional 3D inkjet printing, and methods and systems utilizing same, are provided. The formulation systems are formed of at least a first and second model formulations containing a lactam and a catalyst for inducing anionic ring opening polymerization of the lactam in the first formulation, and an activator for promoting anionic ring opening polymerization of the lactam in the second formulation, and are further characterized as: including in the first and/or second formulation a compound capable of increasing a rate of said polymerization upon exposure to said curing energy; including as an activator a lactam-blocked polyisocyanate; and/or as including in the first model formulation at least one material capable of reducing a melting point of said first model formulation. Formulation systems usable at a selected ratio are also provided.

Abstract: A method of additive manufacturing of three-dimensional objects by sequentially dispensing and solidifying layers. The layers may include (i) stacks of model layers arranged in configured patterns corresponding to shapes of one or more objects and being made of one or more modeling materials; (ii) an intermediate layer surrounding said shapes of one or more objects and comprising at least a support material, and (iii) a flexible overlay surrounding said first intermediate layer, the intermediate layer and flexible overlay forming a flexible sacrificial structure. The model stack or stacks can be removed from the flexible sacrificial structure by application of pressure to the flexible sacrificial structure, separating the model stack from the flexible structure along the intermediate layer.

Abstract: A formulation system usable in additive manufacturing of a three-dimensional object that comprises, in at least a portion thereof, a cyanate ester-containing polymeric network, and additive manufacturing processes employing the formulation system are provided. Also provided are objects obtainable by the additive manufacturing and kits containing the formulation system. The formulation system includes a first modeling material formulation which includes a first curable material which is a thermally-curable cyanate ester and a second modeling material formulation which comprises an activating agent for promoting polymerization of the cyanate ester and is devoid of the first curable material, and further includes a second curable material which is different from the first curable material, and optionally an agent for promoting hardening of the second curable material.

Abstract: Novel support material formulations, characterized as providing a cured support material with improved dissolution rate, while maintaining sufficient mechanical strength, are disclosed. The formulations comprise a water-miscible non-curable polymer, a first water-miscible, curable material and a second, water-miscible material that is selected capable of interfering with intermolecular interactions between polymeric chains formed upon exposing the first water-miscible material to curing energy. Methods of fabricating a three-dimensional object, and a three-dimensional object fabricated thereby are also disclosed.

Abstract: Formulations and methods employing these formulation for fabricating an object by additive manufacturing, such as three-dimensional inkjet printing are provided. The formulations comprise at least 50 weight percents of hydrophilic curable materials, and upon curing, provide a material that is characterized by water absorbance of at least 5%, and by high HDT and impact resistance values. Objects containing cured material made of these formulations are also provided.

Abstract: A method of additive manufacturing for producing a 2-part mold suitable for use in injection molding, comprises: obtaining a computerized 3D representation of a 2-part mold (3D mold); delimiting one or more regions within the 3D mold; assigning a material or a combination of materials to each delimited region which is different from different from materials used in other delimited regions or outside the delimited regions; and producing the 2-part mold by additive manufacturing; wherein the delimiting comprises carrying out an offset from a surface of the 3D mold which is intended to be in contact with injected material, and wherein the offset is carried out within the solid part of the 3D mold.

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.