Abstract: A system (100) for building a three dimensional object includes a powder delivery station (10) for applying a layer of powder material on a building tray (200), a digital printing station (30) for printing a mask pattern on the layer, a sintering station (50) for selectively sintering the portion of the layer that is defined by the mask to be sintered and a stage (250) for repeatedly advancing the building tray (200) to each of the powder delivery station, digital printing station and sintering station to build a plurality of layers that together form the three dimensional object. The mask pattern defines a negative portion of the layer to be sintered. Optionally, the system includes a die compaction station (40) for compacting per layer of powder material.

Abstract: Methods of layerwise fabrication of a three-dimensional object, and objected obtained thereby are provided. The methods are effected by dispensing at least a first modeling formulation and a second modeling formulation to form a core region using both said first and said second modeling formulations, an inner envelope region at least partially surrounding said core region using said first modeling formulation but not said second modeling formulation, and an outer envelope region at least partially surrounding said inner envelope region using said second modeling formulations but not said first modeling formulation; and exposing said layer to curing energy, thereby fabricating the object, The first and second modeling formulations are selected such they differ from one another, when hardened, by at least one of Heat Deflection Temperature (HDT), Izod Impact resistance, Tg and elastic modulus.

Abstract: Formulations usable in additive manufacturing, 3D inkjet printing in particular, of a three-dimensional object that contains a polyimide material, and additive manufacturing utilizing same are provided. The formulations contain a polyimide precursor (e.g., a bismaleimide) and an additional curable material, which is a multifunctional curable material, and are devoid of an organic solvent.

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 3D printing to achieve a desired surface quality on at least one surface of a 3D printed object comprising selecting a base surface having the desired surface quality; and printing the 3D printed object on the base surface, so that the desired surface quality is imparted to one surface of the 3D printed object during printing. The surface quality may be glassiness, roughness, smoothness and texture in general. Objects may thus be manufactured in which electronic components are integrated in or under a glass-like surface.

Abstract: A pressure controlling system for an inkjet printer includes a pressure chamber, a pump fluidically connected to the chamber and adapted for increasing or decreasing the pressure within the pressure chamber, a controllable three port two way valve, and a sensing unit including one or more pressure sensors. The pressure sensing unit is in fluidic communication with the pressure chamber for sensing the pressure therein. The valve has a first port controllably fluidically connectable to the pressure chamber, a second port controllably fluidically connectable to an inkjet print head, and a third port controllably fluidically connectable with atmospheric air. The sensing unit is adapted for sending signals representative of the pressure within the pressure chamber to at least one processor/controller. The pump and the valve are controlled by receiving control signals from the processor/controller(s). There are provided a method for operating the system and a printer including the system.

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 of a three-dimensional object, comprises: dispensing from a first array of nozzles a modeling material formulation containing a polyimide precursor to form a layer in a configured pattern corresponding to a shape of a slice of the object; applying to the layer ultraviolet radiation and infrared radiation from two different radiation sources; and repeating the dispensing and the application of radiation to form a plurality of layers in configured patterns corresponding to shapes of other slices of the object. Optionally, an additional modeling material formulation or a support material formulation is dispensed from a second array of nozzles.

Abstract: Modeling material formulation systems usable in additive manufacturing, 3D inkjet printing in particular, of three-dimensional objects, are provided. The formulations comprise two or more curable materials, such that an average molecular weight of the curable materials in each formulation is no more than 500 grams/mol, such that each formulation features a viscosity of no more than 50 centipoises at a temperature of 35° C. Kits comprising the formulations or formulation systems and additive manufacturing processes utilizing same are also provided.

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: Methods of fabricating three-dimensional objects featuring properties of a soft bodily tissue and three-dimensional objects featuring properties of a soft bodily tissue or of an organ comprising same are provided.

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: Novel support material formulations, characterized as providing a cured support material which is readily removable by contacting with water, are disclosed. The formulations comprise a curable water-soluble mono-functional monomer, a water-miscible polymer and a silicone polyether. Methods of fabricating a three-dimensional object, and a three-dimensional object fabricated thereby are also disclosed.

Abstract: Apparatus for producing a three-dimensional model by sequentially forming layers of photopolymer material one on top of the other responsive to data defining the three-dimensional model is disclosed. The apparatus includes at least one printing head configured to dispense the photopolymer material, an array of LEDs controllable to provide radiation to polymerize the photopolymer material and a controller. The controller is configured to control the at least one printing head to dispense the photopolymer material to sequentially form the layers of material. The controller is also configured to turn on the array of LEDs to provide the radiation to cure the photopolymer material when situated above the model and to turn off the array of LEDs when not situated above the model.

Abstract: A printing head for a printing system is disclosed. The printing head comprises a plurality of compartments, each having an outlet port for depositing liquid and an inlet port separately connectable to a separate liquid container. At least two compartments are in controllable fluid communication with each other, and the printing head comprises an arrangement of sensors configured for generating signals indicative of (i) a filling state of each compartment, and (ii) a fluid communication state between the at least two compartments.

Abstract: A pressure controlling system for an inkjet printer includes a pressure chamber, a pump fluidically connected to the chamber and adapted for increasing or decreasing the pressure within the pressure chamber, a controllable three port two way valve, and a sensing unit including one or more pressure sensors. The pressure sensing unit is in fluidic communication with the pressure chamber for sensing the pressure therein. The valve has a first port controllably fluidically connectable to the pressure chamber, a second port controllably fluidically connectable to an inkjet print head, and a third port controllably fluidically connectable with atmospheric air. The sensing unit is adapted for sending signals representative of the pressure within the pressure chamber to at least one processor/controller. The pump and the valve are controlled by receiving control signals from the processor/controller(s). There are provided a method for operating the system and a printer including the system.

Abstract: A direct inkjet printing system for fabricating a part by an additive manufacturing process includes an ink delivery system operative to circulate the ink, a printhead associated with the ink delivery system, the printhead operative to dispense ink from the ink delivery system through a plurality of nozzles and based on a defined pattern, a building table for receiving the dispensed ink one layer at a time based on the defined pattern, wherein the part is formed from a plurality of layers of the ink dispensed from the printhead and a drying station operative to perform a drying process on layers of the ink dispensed from the printhead on a per layer basis.

Abstract: A method of rendering data for addressable dispensing of material over a working surface, comprises: receiving input image data arranged grid-wise over a plurality of picture-elements; generating an initial map describing a distance field and having a plurality of map-elements each storing distance information corresponding to one picture-element; for each picture-element of at least a portion of the picture-elements: linearly scanning the map independently along a first axis and along a second axis, and updating a respective map-element based on values of map-elements visited during the scan. The distance field can include distances defined perpendicularly to the working surface.

Abstract: Methods for fabricating three-dimensional objects by 3D-inkjet printing technology are provided. The methods utilize a combination of curable materials that polymerize via ring-opening metathesis polymerization (ROMP) and curable materials that polymerize via free-radical polymerization (FRP) for fabricating the object. Systems suitable for performing these methods, kits containing modeling material formulations usable in the methods and objects obtained thereby are also provided.

Abstract: Formulations usable as support material in additive manufacturing such as 3D inkjet printing and which feature a viscosity of no more than 50 cPs at 35° C., are provided. The formulations are composed of at least one hydrophilic curable material which provides, when hardened, a material that is dissolvable or swellable in an aqueous solution; and at least one non-curable material that is capable of being swelled by said hardened material formed of said at least one curable material. Additive manufacturing processes utilizing these formulations and objects obtained thereby are also provided.