Abstract: A method of layerwise fabrication of a three-dimensional object is disclosed. The method comprises, for each of at least a few of the layers: dispensing at least a first modeling formulation and a second modeling formulation to form a core region using both the first and the second modeling formulations, and at least one envelope region at least partially surrounding the core region using one of the first and the second modeling formulations but not the other one of the first and the second modeling formulations. The method can also comprise exposing the layer to curing energy. The first modeling formulation is characterized, when hardened, by heat deflection temperature (HDT) of at least 90° C., and the second modeling formulation is characterized, when hardened, by Izod impact resistance (IR) value of at least 45 J/m.

Abstract: Methods and systems are provided, which convert points in a cloud into a model for 3D printing in a computationally efficient manner and while maintaining and possibly adjusting shape, volume and color information. Methods include deriving, from the points, a crude watertight mesh with respect to the points, e.g., an alpha shape, determining, using normal vectors associated with the points, locations of the points with respect to the mesh (e.g., as being inside, outside or within the model) and using the derived mesh to define the model with respect to the determined locations of the points. Combining the computational geometry approach with the field approach is synergetic and results in better information content of the resulting model for 3D printing while consuming less computational resources.

Abstract: A method of processing data for additive manufacturing of a 3D object comprises: receiving graphic elements defining a surface of the object, and an input color texture to be visible over a surface of the object; transforming the elements to voxelized computer object data; constructing a 3D color map having a plurality of pixels, each being associated with a voxel and being categorized as either a topmost pixel or an internal pixel. Each topmost pixel is associated with a group of internal pixels forming a receptive field for the topmost pixel. A color-value is assigned to each topmost pixel and each internal pixel of a receptive field associated with the topmost pixel, based on the color texture and according to a subtractive color mixing. A material to be used during the additive manufacturing is designated based on the color-value.

Abstract: Provided are methods of fabricating an object, effected by jetting two or more different compositions, each containing a different material or mixture of materials, which, when contacted on a receiving medium, undergo a chemical reaction therebetween to form the building material. The chemical composition of the formed building material is dictated by a ratio of the number of voxels of each composition in a voxel block. Systems for executing the methods, and printed objects obtained thereby are also provided.

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 system for additive manufacturing comprises a dispensing head for dispensing building materials on a working surface, a hardening system for hardening the building materials, a cooling system for evacuating heat away from the building materials, and a computerized controller. A thermal sensing system is mounted above the working surface in a manner that allows relative motion between the sensing system and the working surface, and is configured to generate sensing signals responsively to thermal energy sensed thereby. The controller controls the dispensing head to dispense the building materials in layers, the sensing system to generate the sensing signals only when the sensing system is above the building materials once hardened, and the heat evacuation rate of the cooling system responsively to the sensing signals.

Abstract: A method of additive manufacturing (AM) includes dispensing a first building material formulation to form an outer region, and dispensing a second building material formulation to form an inner region, the outer region surrounding the inner region, the inner and outer regions being shaped to form a layer of the object; exposing the layer to a first curing condition, repeating the dispensing and the exposing to sequentially form a plurality of layers of the object and collectively exposing the plurality of layers to a second curing condition. The selections are such that the first building material formulation is hardened to a higher degree than the second building formulation. The outer regions form a hardened coating that at least partially encapsulates the inner regions. The second curing condition is other than the first curing condition and is selected to increase the degree that the inner region is hardened.

Abstract: A supporting structure built together with an object in an additive manufacturing (AM) process and configured to support an overhang of the object is described. The supporting structure includes a first array of pillars formed with a first material and reinforced with a second material. Each of the pillars in the first array includes a top. At least a portion of the tops in the first array adjoin and define a surface on which the overhang of the object may be supported. The first material is support material.

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: A method of producing an object by sequentially printing layers of construction material one on top of the other, the method comprising: providing the construction material at a first lower temperature; flowing the construction material through a heated flow path in a flow structure to heat the construction material and delivering the heated construction material to a heated reservoir in a printing head; and dispensing the heated construction material from the reservoir to build the object layer by layer.

Abstract: A method for selection of a print head of a three-dimensional (3D) printer includes receiving a model data element having first and second 3D shells, producing an ordered set of slice data elements corresponding to a planar slice of the 3D model, determining an overlapping region of the first and second 3D shells, attributing a property vector value (such as a colorization vector value or a printing material vector value) based on an overlap rule, and selecting a printing head based on the property vector value. A 3D printing system comprises printing heads that can be selected according to the method.

Abstract: Methods and systems are disclosed for selecting a print head of a 3D printing machine to apply 3D printing material at one or more positions in a printed 3D object. Embodiments of the present invention may include, in the selection process one or more elements pertaining for example to: geometry of the received 3D model; colorization of the received 3D model; transparency of the received 3D model; properties of the 3D printing material; and constraints of the 3D printing machine.

Abstract: A method of layerwise fabrication of a three-dimensional object is disclosed. The method comprises, for each of at least a few of the layers: dispensing at least a first modeling formulation and a second modeling formulation to form a core region using both the first and the second modeling formulations, and at least one envelope region at least partially surrounding the core region using one of the first and the second modeling formulations but not the other one of the first and the second modeling formulations. The method can also comprise exposing the layer to curing energy. The first modeling formulation is characterized, when hardened, by heat deflection temperature (HDT) of at least 90° C., and the second modeling formulation is characterized, when hardened, by Izod impact resistance (IR) value of at least 45 J/m.

Abstract: An apparatus for preparing a two-dimensional layer of a three-dimensional object during three-dimensional printing of the object. The apparatus may include a controller; a transparent substrate for receiving a deposited layer of liquid materials on an upper surface thereof; a selective deposition unit that deposits at least one liquid body material and a liquid support material different from the at least one liquid body material, on the transparent substrate according to signals received from the controller; and a selective curing unit that selectively solidifies, by curing irradiation, a portion of the deposited layer of liquid body materials on the transparent substrate according to signals received from the controller, such that some of the liquid body material remains uncured.

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 for additive manufacturing comprises a dispensing head for dispensing building materials on a working surface, a hardening system for hardening the building materials, a cooling system for evacuating heat away from the building materials, and a computerized controller. A thermal sensing system is mounted above the working surface in a manner that allows relative motion between the sensing system and the working surface, and is configured to generate sensing signals responsively to thermal energy sensed thereby. The controller controls the dispensing head to dispense the building materials in layers, the sensing system to generate the sensing signals only when the sensing system is above the building materials once hardened, and the heat evacuation rate of the cooling system responsively to the sensing signals.

Abstract: A method of processing data for additive manufacturing of a 3D object comprises: receiving graphic elements defining a surface of the object, and an input color texture to be visible over a surface of the object; transforming the elements to voxelized computer object data; constructing a 3D color map having a plurality of pixels, each being associated with a voxel and being categorized as either a topmost pixel or an internal pixel. Each topmost pixel is associated with a group of internal pixels forming a receptive field for the topmost pixel. A color-value is assigned to each topmost pixel and each internal pixel of a receptive field associated with the topmost pixel, based on the color texture and according to a subtractive color mixing. A material to be used during the additive manufacturing is designated based on the color-value.

Abstract: A method of monitoring an amount of building material in a cartridge that supplies the material to an additive manufacturing system, comprises introducing gas into the cartridge and measuring the pressure within the cartridge. When the pressure reaches a predetermined level, the amount of building material in the cartridge is determined based on a volume of gas introduced into the cartridge or based on a proxy of the volume.

Abstract: Systems and methods for predefining at least one support structure for at least one three-dimensional object for printing thereof using a three-dimensional printing system are disclosed. Default support structures are replaced by improved support structures or not depending on the result of an assessment, based on predefined rules of the body region in the slice that needs support.