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 system for three-dimensional printing is disclosed. The system comprises: a rotary tray configured to rotate about a vertical axis; a printing head, each having a plurality of separated nozzles; and a controller configured for controlling the inkjet printing head to dispense, during the rotation, droplets of building material in layers, such as to print a three-dimensional object on the tray.

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 system and a method of mitigating color discrepancies in three-dimensional (3D) printing systems may including a plurality of printing heads may include: printing one or more samples according to one or more sample parameters; obtaining a color offset vector from the one or more samples; receiving a model representing a 3D object, the model comprising a plurality of model printing points associated with respective color; analyzing the model in view of the obtained color offset vector to produce a calibrated data structure, adapted to mitigate color discrepancies; and printing the 3D object according to the calibrated data structure.

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 calibrating a print head of a printing system comprises applying voltage to the print head to effect a dispensing of liquid material from the print head; receiving, directly from a sensor within the print head, a signal correlative to a change in an amount of liquid in the print head; and varying the voltage responsively to the signal.

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 printing a three-dimensional (3D) color object, layer-by-layer, comprises: obtaining a 3D CAD specification defining a 3D geometry and a surface color distribution for the color object to be printed, defining regions on a surface of the color object; defining colors for each region based on the CAD specification; determining, using the 3D geometry of the specification, conditions applying at respective regions that are liable to cause color variation, such that using the colors as defined at the respective regions may give rise to a coloration error; selecting color corrections defined for respective determined conditions; correcting the defined colors; and printing the 3D color object with the color corrections.

Abstract: A tubular structure fabricated by additive manufacturing from non-biological building material formulations, and featuring an elongated core, a shell encapsulating the core and an intermediate shell between the core and the shell. Each of the core, the shell and the intermediate shell is made of a different material or a different combination of materials. Both the core and the intermediate shell are sacrificial. Additive manufacturing of the tubular structure is usable for fabricating an object featuring properties of a blood vessel.

Abstract: A system includes a plurality of building trays, a printing station, a powder delivery station, a powder spreading station, a process compaction station and a stage. The printing station prints a mask pattern on each of the plurality of building trays. The powder delivery station applies a dose of powder material on each of the plurality of building trays. The powder spreading station configured to spread the dose of powder material on each of the plurality of building trays. The process compaction station compacts the powder material. The stage concurrently advances the plurality of building trays to each of the stations to concurrently build a single layer on each the plurality of building trays and repeats the advancing to build a plurality of layers on each of the plurality of building trays. A three dimensional object is formed in each of the building trays.

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: Methods, particularly automated methods, are provided, as well as 3D-printed composite and hollow objects and 3D-printing systems for printing them. Methods comprise deriving a central line of a hollow 3D object model, calculating reference point(s) and/or line(s) along an inner surface of the hollow 3D object model, and filling the hollow 3D object model with material that comprises a thread defined with respect to the central line and the reference point(s) and/or line(s) and with filling material surrounding the thread. The support construction thus formed may be removed from the 3D object by pulling on the thread, extracting it and the surrounding support filling from the hollow object, thus enabling 3D-printing of convoluted or elongated hollow objects and objects with narrow openings. The parameters of the thread, such as type of curve and thickness, are selected to ensure thread extraction without risk of tearing or knotting the thread.

Abstract: Curable formulations which are usable in additive manufacturing of three-dimensional objects using a transparent material, and which can be advantageously usable in additive manufacturing systems that utilize a LED curing source are provided. Additive manufacturing processes using same and objects made thereby are also provided.

Abstract: A method of treating an object fabricated from a modeling material by additive manufacturing, comprises exposing the object to visible light having a peak wavelength less than 470 nm, and to a temperature of less than a heat deflection temperature (HDT) of the modeling material.

Abstract: A method for dynamically controlling layer thickness during an additive manufacturing process of building a block including an object with layers of powder material, detecting a height of the block after each layer is compacted, determining a delta between the detected height and a height in a computer model defining slices of the block and compensating for the determined delta in subsequent cycles. A cycle in the additive manufacturing process includes selectively printing a layer pattern, spreading a powder layer over the layer pattern with a spreader and compacting the powder layer with the layer pattern.

Abstract: A method of printing a three-dimensional object (90) including: providing a 3D inkjet printing system including: a printing chamber (162) accommodating a printing unit (120) having an inkjet printing head and a curing subunit (124), and a supply unit (130) including a modeling material and a support material; and printing the 3D object (90) in multiple consecutive layers according to a predefined printing sequence, wherein for at least one of the multiple consecutive layers the predefined printing sequence for the same respective layer includes depositing and curing the modeling material and the support material separately from each other either in time or in space. Some embodiments may include controlling a concentration of oxygen in the printing chamber (162) to be in a predefined oxygen concentration range. Some embodiments may include controlling a temperature in the printing chamber (162) to be in a predefined temperature range.

Abstract: An additive manufacturing (AM) system includes a carriage that deposits material in a defined pattern and a building platform that receives material deposited from the carriage. The carriage includes a pre-heating assembly with a plurality of pre-heating chambers and a printing block with a plurality of slots for receiving a plurality of printing heads. The carriage is equipped with more pre-heating chambers than head slots.

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 tubular structure fabricated by additive manufacturing from non-biological building material formulations, and featuring an elongated core, a shell encapsulating the core and an intermediate shell between the core and the shell. Each of the core, the shell and the intermediate shell is made of a different material or a different combination of materials. Both the core and the intermediate shell are sacrificial. Additive manufacturing of the tubular structure is usable for fabricating an object featuring properties of a blood vessel.

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.