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: 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: A waste management system for an AM device includes a waste container, an air cleaning device installed within an enclosure of the AM device, a first conduit and at least one second conduit. The air cleaning device condense vapors formed within an enclosure of the AM device during operation of the AM device. The first conduit directs the condensed vapors in a liquid state from the air cleaning device to the waste container and the at least one second conduit directs waste accumulated during operation of the AM device to the waste container. The waste container stores waste accumulated by the AM device during operation of the AM device.

Abstract: An additive manufacturing method for printing an object includes receiving three-dimensional printing data corresponding to the object, defining an internal region of the object to be formed with a structured air pocket and printing the object with an additive manufacturing system. The object includes an internal region formed with a structured air pocket.

Abstract: A method of additive manufacturing of a three-dimensional object, comprises: sequentially dispensing and solidifying layers to form on a surface a sacrificial structure. In embodiments the sacrificial structure comprises a bulk volume and heating cells embedded in the bulk volume, where the heating cells release more heat than the bulk volume upon the solidification of the layers. In embodiments, the sacrificial structure comprises pinning structures embedded in the bulk volume. The method also comprises sequentially dispensing and solidifying layers to form the three-dimensional object on a portion of the sacrificial structure.

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: 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: A method of providing nozzle calibration parameters for a 3D printer comprises: printing an arc pattern, printing an X-Y align pattern, and printing a head calibration pattern, measuring actual positions of drops, calculating deviations of said measured actual positions from expected positions, and calculating calibration parameters to correct for the deviations. Indicator drops may be used to allow built-in image recognition to find the calibration drops, and a cam system is provided to guide nozzle wipers.

Abstract: A method of additive manufacturing of a three-dimensional object, comprises: sequentially dispensing and solidifying layers to form on a surface a sacrificial structure. In embodiments the sacrificial structure comprises a bulk volume and heating cells embedded in the bulk volume, where the heating cells release more heat than the bulk volume upon the solidification of the layers. In embodiments, the sacrificial structure comprises pinning structures embedded in the bulk volume. The method also comprises sequentially dispensing and solidifying layers to form the three-dimensional object on a portion of the sacrificial structure.

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 providing nozzle calibration parameters for a 3D printer comprises: printing an arc pattern, printing an X-Y align pattern, and printing a head calibration pattern, measuring actual positions of drops, calculating deviations of said measured actual positions from expected positions, and calculating calibration parameters to correct for the deviations. Indicator drops may be used to allow built-in image recognition to find the calibration drops, and a cam system is provided to guide nozzle wipers.

Abstract: System for controlling fabrication of three-dimensional objects, layer by layer are disclosed. The system includes a printing assembly having an irradiation unit and a printing head, the printing assembly is movable between a printing area and a service area. The system further includes a light sensor positioned at the service area to measure the output radiation power of the irradiation unit and a controller to receive information from the sensor and to automatically adjust the electrical power supplied to the irradiation unit.

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: System for controlling fabrication of three-dimensional objects, layer by layer are disclosed. The system includes a printing assembly having an irradiation unit and a printing head, the printing assembly is movable between a printing area and a service area. The system further includes a light sensor positioned at the service area to measure the output radiation power of the irradiation unit and a controller to receive information from the sensor and to automatically adjust the electrical power supplied to the irradiation unit.

Abstract: Embodiments of the present invention are directed to a system and method for controlling fabrication of three-dimensional objects, layer by layer, the system comprising a printing assembly, including an irradiation unit and a printing head, the printing assembly is movable between a printing area and a service area. A light sensor positioned at the service area to measure output radiation power of the irradiation unit at a printing plane and a controller to receive information from the sensor and to automatically adjust electrical power supplied to the irradiation unit based on the information.

Abstract: A printing method includes controlling timing parameters for application of electrical pulses to a piezoelectric nozzle of an inkjet printing head so as to dispense droplets of a material from the nozzle. The timing parameters are controlled to introduce gas bubbles into the droplets of material so as to reduce the density of the material to a selected density value that is less than a natural density of the material.

Abstract: A printing method includes controlling timing parameters for application of electrical pulses to a piezoelectric nozzle of an inkjet printing head so as to dispense droplets of a material from the nozzle. The timing parameters are controlled to introduce gas bubbles into the droplets of material so as to reduce the density of the material to a selected density value that is less than a natural density of the material.

Abstract: Embodiments of the invention are directed to systems and methods for accurate positioning of a unit movable by a drive system. The method may include adjusting tension of a resilient element of the drive system to reduce hysteresis motion errors of the resilient element below a predetermined threshold by performing measurements of the hysteresis motion errors of the resilient element for two or more tension values and selecting a tension value for which the hysteresis motion error is below the threshold.

Abstract: An Apparatus for polymerizing photoactive materials included in a liquid material by electromagnetic radiation, by dispensing the liquid material layer-wise into a container and irradiating the accumulated layers by a curing radiation, wherein a substantial part of the radiation is well transmitted through the photoactive material.

Abstract: Method and apparatus for polymerizing photoactive materials included in a liquid material by electromagnetic radiation, by dispensing the liquid material layer-wise into a container and irradiating the accumulated layers by a curing radiation, wherein a substantial part of the radiation is well transmitted through the photoactive material.