WO2025141568A1 - Method and system for additive manufacturing hangable object - Google Patents

Abstract

An object assembly (410) comprises a first plurality of layers formed by additive manufacturing and defining a three-dimensional object (414), and a second plurality of layers formed by additive manufacturing and defining a three-dimensional hangable element (410) detachably protruding out of an outer surface of the object.

Description

METHOD AND SYSTEM FOR ADDITIVE MANUFACTURING HANGABLE OBJECT

RELATED APPLICATION

This application claims the benefit of priority of U.S. Provisional Patent Application No. 63/615,802 filed on December 29, 2023, the contents of which are incorporated herein by reference in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to additive manufacturing and, more particularly, but not exclusively, to a method and system for additive manufacturing a hangable object.

Additive manufacturing (AM) is generally a process in which a three-dimensional (3D) object is manufactured utilizing a computer model of the objects. Such a process is used in various fields, such as design related fields for purposes of visualization, demonstration and mechanical prototyping, as well as for rapid manufacturing (RM). The basic operation of any AM system consists of slicing a three-dimensional computer model into thin cross sections, translating the result into two-dimensional position data and feeding the data to control equipment which manufacture a three-dimensional structure in a layerwise manner.

One type of AM is three-dimensional inkjet printing processes. In this process, a building material is dispensed from a dispensing head having a set of nozzles to deposit layers on a supporting structure. Depending on the building material, the layers may then be cured or solidified using a suitable device. Various three-dimensional inkjet printing techniques exist and are disclosed in, e.g., U.S. Patent Nos. 6,259,962, 6,569,373, 6,658,314, 6,850,334, 7,183,335, 7,209,797, 7,225,045, 7,300,619, 7,479,510, 7,500,846, and 7,962,237.

In extrusion-based AM, e.g., fused deposition modeling, a 3D object is manufactured by extruding a viscous, flowable thermoplastic or filled thermoplastic material from a print head along toolpaths at a controlled extrusion rate. The extruded flow of material is deposited as a sequence of roads or beads following the defined toolpaths. The material fuses to previously deposited material and solidifies upon a drop in temperature. The print head includes a liquefier which receives a supply of the thermoplastic material in the form of a flexible filament, and a nozzle tip for dispensing molten material. Various three-dimensional extrusion-based AM techniques exist and are disclosed in, e.g., such as those disclosed in U.S. Patent Nos. 5,503,785, 7,384,255, 7,604,470, 7,625,200, 8,153,182, 8,419,996, 8,647,102, 8,926,882 and 10,513,104.

Other AM techniques include selective laser sintering, powder or binder jetting, electronbeam melting, electrophotographic imaging, and stereolithographic processes.

SUMMARY OF THE INVENTION

According to some embodiments of the invention the present invention there is provided a hangable object assembly. The object assembly comprises a first plurality of layers formed by additive manufacturing and defining a three-dimensional object, and a second plurality of layers formed by additive manufacturing and defining a three-dimensional hangable element detachably protruding out of an outer surface of the object.

According to an aspect of some embodiments of the present invention there is provided a method of additive manufacturing. The method comprises forming by additive manufacturing a first plurality of layers in configured patterns corresponding to shapes of slices of a three- dimensional object, and forming by additive manufacturing a second plurality of layers in configured patterns corresponding to shapes of slices of a three-dimensional hangable element detachably protruding out of an outer surface of the object, thereby manufacturing a hangable object assembly.

According to some embodiments of the invention the hangable element comprises a breakable portion adjacent to the outer surface of the object.

According to some embodiments of the invention the breakable portion is tapered.

According to some embodiments of the invention the breakable portion comprises air voids.

According to some embodiments of the invention a material of the breakable portion is different than a material of other portions of the hangable element.

According to some embodiments of the invention the additive manufacturing is inkjet printing, wherein the breakable portion comprises an inkjet-printed digital material.

According to some embodiments of the invention the hangable element comprises a peelable portion adjacent to the outer surface of the object.

According to some embodiments of the invention a portion of the second plurality of layers is formed together with a portion of the first plurality of layers to form an internal portion of the hangable element that is embedded within the object.

According to some embodiments of the invention the internal portion of the hangable element has a tapered or a flared shape. According to some embodiments of the invention a distal end of the hangable element with respect to the outer surface of the object is shaped to form a connecting member.

According to some embodiments of the invention the distal end is shaped as a hook or an eyelet.

According to some embodiments of the invention the connecting member is a connector shaped and sized to match a hanger in a male-female connection relation.

According to some embodiments of the invention the object assembly also comprises the hanger.

According to some embodiments of the invention the hangable element comprises an identifiable pattern on an outer surface of the hangable element.

According to some embodiments of the invention the hangable element comprises an identifiable pattern on an outer surface of the hangable element, and wherein the hanger also has the identifiable pattern on an outer surface of the hanger.

According to some embodiments of the invention the identifiable pattern is user-specific.

According to some embodiments of the invention the hangable element comprises a core and a coating, and wherein the core is more rigid than the coating.

According to some embodiments of the invention a rigidity of the hangable element increases gradually away from the object.

According to some embodiments of the invention the first and the second pluralities of layers are formed by the same additive manufacturing technology.

According to some embodiments of the invention the first and the second pluralities of layers are formed by different additive manufacturing technology.

According to some embodiments of the invention at least one of the first and the second pluralities of layers are formed by inkjet printing.

According to some embodiments of the invention the method comprises manufacturing the hanger by additive manufacturing.

According to some embodiments of the invention the method comprises manufacturing a plurality of hangable object assemblies each having a connector shaped and sized to match the hanger in a male-female connection relation.

According to some embodiments of the invention the method comprises applying a post additive manufacturing process to the hangable object assembly, and detaching the hangable element from the object following the application of the post additive manufacturing process. According to some embodiments of the invention the second plurality of layers are made of a curable material, and the method comprising curing the second plurality of layers in a manner that an extent of the curing is higher at the breakable portion than at other portions.

According to some embodiments of the invention the method comprises automatically selecting at least one property of the pattern based on a material from which the hangable element is formed.

According to some embodiments of the invention the method comprises applying a post additive manufacturing process to the hangable object assembly, wherein at least one of a type and a protocol of the post additive manufacturing process is selected based on the identifiable pattern.

According to some embodiments of the invention the method comprises calculating an expected mass and/or volume of the object, and automatically selecting at least one of a size and a shape of the hangable element based on the calculated mass and/or volume.

According to some embodiments of the invention the hangable element protrudes out of the outer surface of the object at a protruding location over the surface, and the method comprises calculating an expected a center-of-mass of the object, and automatically selecting the protruding location based on the calculated center-of-mass.

According to some embodiments of the invention the method comprises prior to the forming the first and the second pluralities of layers: displaying a graphical user interface (GUI) having a protruding location control, for allowing a user to select a protruding location over the outer surface of the object at which the hangable element protrudes out of the surface; receiving protruding location input from the protruding location control; and displaying on the GUI an expected hanging orientation of the hangable object assembly responsively to the input.

According to an aspect of some embodiments of the present invention there is provided a computerized controller for an additive manufacturing system. The computerized controller comprises a circuit configured for operating the additive manufacturing system to execute the method as delineated above and optionally and preferably as further detailed below.

According to an aspect of some embodiments of the present invention there is provided an additive manufacturing system. The system comprises a dispensing head, a working surface and the computerized controller.

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

Implementation of the method and/or system of embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of embodiments of the method and/or system of the invention, several selected tasks could be implemented by hardware, by software or by firmware or by a combination thereof using an operating system.

For example, hardware for performing selected tasks according to embodiments of the invention could be implemented as a chip or a circuit. As software, selected tasks according to embodiments of the invention could be implemented as a plurality of software instructions being executed by a computer using any suitable operating system. In an exemplary embodiment of the invention, one or more tasks according to exemplary embodiments of method and/or system as described herein are performed by a data processor, such as a computing platform for executing a plurality of instructions. Optionally, the data processor includes a volatile memory for storing instructions and/or data and/or a non-volatile storage, for example, a magnetic hard-disk and/or removable media, for storing instructions and/or data. Optionally, a network connection is provided as well. A display and/or a user input device such as a keyboard or mouse are optionally provided as well.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings and images. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

FIGs. 1A-D are schematic illustrations of an additive manufacturing system according to some embodiments of the invention;

FIGs. 2A-2C are schematic illustrations of printing heads according to some embodiments of the present invention; FIGs. 3A and 3B are schematic illustrations demonstrating coordinate transformations according to some embodiments of the present invention;

FIGs. 4A and 4B are schematic illustrations of a hangable object assembly, according to some embodiments of the present invention;

FIGs. 5A-H are schematic illustrations showing magnified views of hangable elements according to some embodiments of the present invention;

FIGs. 6A-F are schematic illustrations of representative example of shapes and sizes for an immobilized structure to which a connecting member can connect according to some embodiments of the present invention;

FIGs. 7A and 7B are schematic illustrations of a hangable element in embodiments of the present invention in which the rigidity of the hangable element increases away from an object to which it is connected;

FIGs. 7C and 7D are schematic illustrations of a hangable element in embodiments of the present invention in which the hangable element comprises a core and a coating;

FIG. 8 is a flowchart diagram of a method suitable for additive manufacturing of a hangable object assembly in layers, according to various exemplary embodiments of the present invention;

FIG. 9 is a schematic illustration of a graphical user interface according to some embodiments of the present invention; and

FIG. 10 is an image of an object assembly manufactured during experiments performed according to some embodiments of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to additive manufacturing and, more particularly, but not exclusively, to a method and system for additive manufacturing a hangable object.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

The method and system of the present embodiments manufacture three-dimensional objects based on computer object data in a layerwise manner by forming a plurality of layers in a configured pattern corresponding to the shape of the objects. The computer object data can be in any known format, including, without limitation, a Standard Tessellation Language (STL) or a StereoLithography Contour (SLC) format, an OBJ File format (OBJ), a 3D Manufacturing Format (3MF), Virtual Reality Modeling Language (VRML), Additive Manufacturing File (AMF) format, Drawing Exchange Format (DXF), Polygon File Format (PLY), or any other format suitable for Computer-Aided Design (CAD).

The term "object" as used herein refers to a whole object or a part thereof.

Each layer is formed by an additive manufacturing apparatus which scans a two- dimensional surface and patterns it. While scanning, the apparatus visits a plurality of target locations on the two-dimensional layer or surface, and decides, for each target location or a group of target locations, whether or not the target location or group of target locations is to be occupied by building material formulation, and which type of building material formulation is to be delivered thereto. The decision is made according to a computer image of the surface.

The present embodiments contemplate any AM technique known in the art, including, without limitation, three-dimensional printing, fused deposition modeling, selective laser sintering, powder or binder jetting, stereolithography, powder binding, electron-beam melting, electrophotographic imaging.

In preferred embodiments of the present invention the AM comprises three-dimensional printing, more preferably three-dimensional inkjet printing. In these embodiments a building material is dispensed from a printing head having one or more arrays of nozzles to deposit building material in layers on a supporting structure. The AM apparatus thus dispenses building material in target locations which are to be occupied and leaves other target locations void. The apparatus typically includes a plurality of arrays of nozzles, each of which can be configured to dispense a different building material. This is typically achieved by providing the printing head with a plurality of fluid channels are separated from each other such that there is no fluid communication therebetween, wherein each channel receives a different building material through a separate inlet and conveys it to a different array of nozzles.

Thus, different target locations can be occupied by different building material formulations. The types of building material formulations can be categorized into two major categories: modeling material formulation and support material formulation. The support material formulation serves as a supporting matrix or construction for supporting the object or object parts during the fabrication process and/or other purposes, e.g., providing hollow or porous objects. Support constructions may additionally include modeling material formulation elements, e.g. for further support strength. The modeling material formulation is generally a composition which is formulated for use in additive manufacturing and which is able to form a three-dimensional object on its own, without having to be mixed or combined with any other substance.

The final three-dimensional object is made of the modeling material formulation or a combination of modeling material formulations or modeling and support material formulations or modification thereof (e.g., following curing). All these operations are well-known to those skilled in the art of solid freeform fabrication.

In some exemplary embodiments of the invention an object is manufactured by dispensing two or more different modeling material formulations, each material formulation from a different array of nozzles (belonging to the same or different printing heads) of the AM apparatus. In some embodiments, two or more such arrays of nozzles that dispense different modeling material formulations are both located in the same printing head of the AM apparatus. In some embodiments, arrays of nozzles that dispense different modeling material formulations are located in separate printing heads, for example, a first array of nozzles dispensing a first modeling material formulation is located in a first printing head, and a second array of nozzles dispensing a second modeling material formulation is located in a second printing head.

In some embodiments, an array of nozzles that dispense a modeling material formulation and an array of nozzles that dispense a support material formulation are both located in the same printing head. In some embodiments, an array of nozzles that dispense a modeling material formulation and an array of nozzles that dispense a support material formulation are located in separate printing heads.

A representative and non-limiting example of a system 110 suitable for AM of an object 112 according to some embodiments of the present invention is illustrated in FIG. 1A. System 110 comprises an additive manufacturing apparatus 114 having a dispensing unit 16 which comprises a plurality of printing heads. Each head preferably comprises one or more arrays of nozzles 122, typically mounted on an orifice plate 121, as illustrated in FIGs. 2A-C described below, through which a liquid building material formulation 124 is dispensed.

Preferably, but not obligatorily, apparatus 114 is a three-dimensional printing apparatus, in which case the printing heads are printing heads, and the building material formulation is dispensed via inkjet technology. This need not necessarily be the case, since, for some applications, it may not be necessary for the additive manufacturing apparatus to employ three-dimensional printing techniques. Representative examples of additive manufacturing apparatus contemplated according to various exemplary embodiments of the present invention include, without limitation, fused deposition modeling apparatus and fused material formulation deposition apparatus.

Each printing head is optionally and preferably fed via one or more building material formulation reservoirs which may optionally include a temperature control unit (e.g. , a temperature sensor and/or a heating device), and a material formulation level sensor. To dispense the building material formulation, a voltage signal is applied to the printing heads to selectively deposit droplets of material formulation via the printing head nozzles, for example, as in piezoelectric inkjet printing technology. Another example includes thermal inkjet printing heads. In these types of heads, there are heater elements in thermal contact with the building material formulation, for heating the building material formulation to form gas bubbles therein, upon activation of the heater elements by a voltage signal. The gas bubbles generate pressures in the building material formulation, causing droplets of building material formulation to be ejected through the nozzles. Piezoelectric and thermal printing heads are known to those skilled in the art of solid freeform fabrication. For any types of inkjet printing heads, the dispensing rate of the head depends on the number of nozzles, the type of nozzles and the applied voltage signal rate (frequency).

In an embodiment of the invention, the overall number of dispensing nozzles or nozzle arrays is selected such that half of the dispensing nozzles are designated to dispense support material formulation and half of the dispensing nozzles are designated to dispense modeling material formulation, i.e. the number of nozzles jetting modeling material formulations is the same as the number of nozzles jetting support material formulation. The ratio of modeling material dispensing arrays to support material dispensing arrays may vary. In the representative example of FIG. 1A, four printing heads 16a, 16b, 16c and 16d are illustrated. Each of heads 16a, 16b, 16c and 16d has a nozzle array. In this Example, heads 16a and 16b can be designated for modeling material formulation/s and heads 16c and 16d can be designated for support material formulation. Thus, head 16a can dispense one modeling material formulation, head 16b can dispense another modeling material formulation and heads 16c and 16d can both dispense support material formulation. In an alternative embodiment, heads 16c and 16d, for example, may be combined in a single head having two nozzle arrays for depositing support material formulation. In a further alternative embodiment any one or more of the printing heads may have more than one nozzle arrays for depositing more than one material formulation, e.g. two nozzle arrays for depositing two different modeling material formulations or a modeling material formulation and a support material formulation, each formulation via a different array or number of nozzles. Yet it is to be understood that it is not intended to limit the scope of the present invention and that the number of modeling material formulation printing heads (modeling heads) and the number of support material formulation printing heads (support heads) may differ. Generally, the number of arrays of nozzles that dispense modeling material formulation, the number of arrays of nozzles that dispense support material formulation, and the number of nozzles in each respective array are selected such as to provide a predetermined ratio, a, between the maximal dispensing rate of the support material formulation and the maximal dispensing rate of modeling material formulation. The value of the predetermined ratio, a, is preferably selected to ensure that in each formed layer, the height of modeling material formulation equals the height of support material formulation. Typical values for a are from about 0.6 to about 1.5.

As used herein throughout the term “about” refers to ± 10 %.

For example, for a = 1, the overall dispensing rate of support material formulation is generally the same as the overall dispensing rate of the modeling material formulation when all the arrays of nozzles operate.

Apparatus 114 can comprise, for example, M modeling heads each having m arrays of p nozzles, and S support heads each having s arrays of q nozzles such that Mxmxp = Sxsxq. Each of the Mxm modeling arrays and Sxs support arrays can be manufactured as a separate physical unit, which can be assembled and disassembled from the group of arrays. In this embodiment, each such array optionally and preferably comprises a temperature control unit and a material formulation level sensor of its own, and receives an individually controlled voltage for its operation.

Apparatus 114 can further comprise a solidifying device 324 which can include any device configured to emit light, heat or the like that may cause the deposited material formulation to harden. For example, solidifying device 324 can comprise one or more radiation sources, which can be, for example, an ultraviolet or visible or infrared lamp, or other sources of electromagnetic radiation, or electron beam source, depending on the modeling material formulation being used. In some embodiments of the present invention, solidifying device 324 serves for curing or solidifying the modeling material formulation.

In addition to solidifying device 324, apparatus 114 optionally and preferably comprises an additional radiation source 328. Radiation source 328 can be the same as the radiation source employed by device 18 (e.g., an ultraviolet radiation source) or it can be configured to effect solvent evaporation, in which case it optionally and preferably generates infrared radiation. In some embodiments of the present invention apparatus 114 comprises cooling system 134 such as one or more fans or the like

The printing head(s) and radiation source are preferably mounted in a frame or block 128 which is preferably operative to reciprocally move over a tray 360, which serves as the working surface. In some embodiments of the present invention the radiation sources are mounted in the block such that they follow in the wake of the printing heads to at least partially cure or solidify the material formulations just dispensed by the printing heads. Tray 360 is positioned horizontally. According to the common conventions an X-Y-Z Cartesian coordinate system is selected such that the X-Y plane is parallel to tray 360. Tray 360 is preferably configured to move vertically (along the Z direction), typically downward. In various exemplary embodiments of the invention, apparatus 114 further comprises one or more leveling devices 132, e.g. a roller 326. Leveling device 326 serves to straighten, level and/or establish a thickness of the newly formed layer prior to the formation of the successive layer thereon. Leveling device 326 preferably comprises a waste collection device 136 for collecting the excess material formulation generated during leveling. Waste collection device 136 may comprise any mechanism that delivers the material formulation to a waste tank or waste cartridge.

In use, the printing heads of unit 16 move in a scanning direction, which is referred to herein as the X direction, and selectively dispense building material formulation in a predetermined configuration in the course of their passage over tray 360. The building material formulation typically comprises one or more types of support material formulation and one or more types of modeling material formulation. The passage of the printing heads of unit 16 is followed by the curing of the modeling material formulation(s) by radiation source 126. In the reverse passage of the heads, back to their starting point for the layer just deposited, an additional dispensing of building material formulation may be carried out, according to predetermined configuration. In the forward and/or reverse passages of the printing heads, the layer thus formed may be straightened by leveling device 326, which preferably follows the path of the printing heads in their forward and/or reverse movement. Once the printing heads return to their starting point along the X direction, they may move to another position along an indexing direction, referred to herein as the Y direction, and continue to build the same layer by reciprocal movement along the X direction. Alternately, the printing heads may move in the Y direction between forward and reverse movements or after more than one forward-reverse movement. The series of scans performed by the printing heads to complete a single layer is referred to herein as a single scan cycle. Once the layer is completed, tray 360 is lowered in the Z direction to a predetermined Z level, according to the desired thickness of the layer subsequently to be printed. The procedure is repeated to form three-dimensional object 112 in a layerwise manner.

In another embodiment, tray 360 may be displaced in the Z direction between forward and reverse passages of the printing head of unit 16, within the layer. Such Z displacement is carried out in order to cause contact of the leveling device with the surface in one direction and prevent contact in the other direction.

System 110 optionally and preferably comprises a building material supply system 42 which comprises the building material formulation containers or cartridges and supplies a plurality of building material formulations to fabrication apparatus 114.

A controller 20 controls fabrication apparatus 114 and optionally and preferably also supply system 42. Controller 20 typically includes an electronic circuit configured to perform the controlling operations. Controller 20 preferably communicates with a host computer 24 which transmits digital data pertaining to fabrication instructions based on computer object data, e.g., a CAD configuration represented on a computer readable medium in a form of a Standard Tessellation Language (STL) format or the like. Typically, controller 20 controls the voltage applied to each printing head or each nozzle array and the temperature of the building material formulation in the respective printing head or respective nozzle array.

Once the manufacturing data is loaded to controller 20 it can operate without user intervention. In some embodiments, controller 20 receives additional input from the operator, e.g., using computer 24 or using a user interface 116 communicating with unit 20. User interface 116 can be of any type known in the art, such as, but not limited to, a keyboard, a touch screen and the like. For example, controller 20 can receive, as additional input, one or more building material formulation types and/or attributes, such as, but not limited to, color, characteristic distortion and/or transition temperature, viscosity, electrical property, magnetic property. Other attributes and groups of attributes are also contemplated.

Another representative and non-limiting example of a system 10 suitable for AM of an object according to some embodiments of the present invention is illustrated in FIGs. 1B-D. FIGs. 1B-D illustrate a top view (FIG. IB), a side view (FIG. 1C) and an isometric view (FIG. ID) of system 10.

In the present embodiments, system 10 comprises a tray 12 and a plurality of inkjet printing heads 16, each having one or more arrays of nozzles with respective one or more pluralities of separated nozzles. The material used for the three-dimensional printing is supplied to heads 16 by a building material supply system 42. Tray 12 can have a shape of a disk or it can be annular. Nonround shapes are also contemplated, provided they can be rotated about a vertical axis.

Tray 12 and heads 16 are optionally and preferably mounted such as to allow a relative rotary motion between tray 12 and heads 16. This can be achieved by (i) configuring tray 12 to rotate about a vertical axis 14 relative to heads 16, (ii) configuring heads 16 to rotate about vertical axis 14 relative to tray 12, or (iii) configuring both tray 12 and heads 16 to rotate about vertical axis 14 but at different rotation velocities (e.g., rotation at opposite direction). While some embodiments of system 10 are described below with a particular emphasis to configuration (i) wherein the tray is a rotary tray that is configured to rotate about vertical axis 14 relative to heads 16, it is to be understood that the present application contemplates also configurations (ii) and (iii) for system 10. Any one of the embodiments of system 10 described herein can be adjusted to be applicable to any of configurations (ii) and (iii), and one of ordinary skills in the art, provided with the details described herein, would know how to make such adjustment.

In the following description, a direction parallel to tray 12 and pointing outwardly from axis 14 is referred to as the radial direction r, a direction parallel to tray 12 and perpendicular to the radial direction r is referred to herein as the azimuthal direction <p, and a direction perpendicular to tray 12 is referred to herein is the vertical direction z-

The radial direction r in system 10 enacts the indexing direction y in system 110, and the azimuthal direction cp enacts the scanning direction x in system 110. Therefore, the radial direction is interchangeably referred to herein as the indexing direction, and the azimuthal direction is interchangeably referred to herein as the scanning direction.

The term “radial position,” as used herein, refers to a position on or above tray 12 at a specific distance from axis 14. When the term is used in connection to a printing head, the term refers to a position of the head which is at specific distance from axis 14. When the term is used in connection to a point on tray 12, the term corresponds to any point that belongs to a locus of points that is a circle whose radius is the specific distance from axis 14 and whose center is at axis 14.

The term “azimuthal position,” as used herein, refers to a position on or above tray 12 at a specific azimuthal angle relative to a predetermined reference point. Thus, radial position refers to any point that belongs to a locus of points that is a straight line forming the specific azimuthal angle relative to the reference point.

The term “vertical position,” as used herein, refers to a position over a plane that intersect the vertical axis 14 at a specific point. Tray 12 serves as a building platform for three-dimensional printing. The working area on which one or objects are printed is typically, but not necessarily, smaller than the total area of tray 12. In some embodiments of the present invention the working area is annular. The working area is shown at 26. In some embodiments of the present invention tray 12 rotates continuously in the same direction throughout the formation of object, and in some embodiments of the present invention tray reverses the direction of rotation at least once (e.g., in an oscillatory manner) during the formation of the object. Tray 12 is optionally and preferably removable. Removing tray 12 can be for maintenance of system 10, or, if desired, for replacing the tray before printing a new object. In some embodiments of the present invention system 10 is provided with one or more different replacement trays (e.g., a kit of replacement trays), wherein two or more trays are designated for different types of objects (e.g., different weights) different operation modes (e.g., different rotation speeds), etc. The replacement of tray 12 can be manual or automatic, as desired. When automatic replacement is employed, system 10 comprises a tray replacement device 36 configured for removing tray 12 from its position below heads 16 and replacing it by a replacement tray (not shown). In the representative illustration of FIG. IB tray replacement device 36 is illustrated as a drive 38 with a movable arm 40 configured to pull tray 12, but other types of tray replacement devices are also contemplated.

Exemplified embodiments for the printing head 16 are illustrated in FIGs. 2A-2C. These embodiments can be employed for any of the AM systems described above, including, without limitation, system 110 and system 10.

FIGs. 2A-B illustrate a printing head 16 with one (FIG. 2A) and two (FIG. 2B) nozzle arrays 22. The nozzles in the array are preferably aligned linearly, along a straight line. In embodiments in which a particular printing head has two or more linear nozzle arrays, the nozzle arrays are optionally and preferably can be parallel to each other. When a printing head has two or more arrays of nozzles (e.g., FIG. 2B) all arrays of the head can be fed with the same building material formulation, or at least two arrays of the same head can be fed with different building material formulations.

When a system similar to system 110 is employed, all printing heads 16 are optionally and preferably oriented along the indexing direction with their positions along the scanning direction being offset to one another.

When a system similar to system 10 is employed, all printing heads 16 are optionally and preferably oriented radially (parallel to the radial direction) with their azimuthal positions being offset to one another. Thus, in these embodiments, the nozzle arrays of different printing heads are not parallel to each other but are rather at an angle to each other, which angle being approximately equal to the azimuthal offset between the respective heads. For example, one head can be oriented radially and positioned at azimuthal position <pi, and another head can be oriented radially and positioned at azimuthal position 92. In this example, the azimuthal offset between the two heads is 91-92, and the angle between the linear nozzle arrays of the two heads is also 91-92.

In some embodiments, two or more printing heads can be assembled to a block of printing heads, in which case the printing heads of the block are typically parallel to each other. A block including several inkjet printing heads 16a, 16b, 16c is illustrated in FIG. 2C.

In some embodiments, system 10 comprises a stabilizing structure 30 positioned below heads 16 such that tray 12 is between stabilizing structure 30 and heads 16. Stabilizing structure 30 may serve for preventing or reducing vibrations of tray 12 that may occur while inkjet printing heads 16 operate. In configurations in which printing heads 16 rotate about axis 14, stabilizing structure 30 preferably also rotates such that stabilizing structure 30 is always directly below heads 16 (with tray 12 between heads 16 and tray 12).

Tray 12 and/or printing heads 16 is optionally and preferably configured to move along the vertical direction z, parallel to vertical axis 14 so as to vary the vertical distance between tray 12 and printing heads 16. In configurations in which the vertical distance is varied by moving tray 12 along the vertical direction, stabilizing structure 30 preferably also moves vertically together with tray 12. In configurations in which the vertical distance is varied by heads 16 along the vertical direction, while maintaining the vertical position of tray 12 fixed, stabilizing structure 30 is also maintained at a fixed vertical position.

The vertical motion can be established by a vertical drive 28. Once a layer is completed, the vertical distance between tray 12 and heads 16 can be increased (e.g., tray 12 is lowered relative to heads 16) by a predetermined vertical step, according to the desired thickness of the layer subsequently to be printed. The procedure is repeated to form a three-dimensional object in a layerwise manner.

The operation of inkjet printing heads 16 and optionally and preferably also of one or more other components of system 10, e.g., the motion of tray 12, are controlled by a controller 20. The controller can have an electronic circuit and a non-volatile memory medium readable by the circuit, wherein the memory medium stores program instructions which, when read by the circuit, cause the circuit to perform control operations as further detailed below.

Controller 20 can also communicate with a host computer 24 which transmits digital data pertaining to fabrication instructions based on computer object data, e.g., in a form of a Standard Tessellation Language (STL) or a StereoLithography Contour (SLC) format, Virtual Reality Modeling Language (VRML), Additive Manufacturing File (AMF) format, Drawing Exchange Format (DXF), Polygon File Format (PLY) or any other format suitable for Computer-Aided Design (CAD). The object data formats are typically structured according to a Cartesian system of coordinates. In these cases, computer 24 preferably executes a procedure for transforming the coordinates of each slice in the computer object data from a Cartesian system of coordinates into a polar system of coordinates. Computer 24 optionally and preferably transmits the fabrication instructions in terms of the transformed system of coordinates. Alternatively, computer 24 can transmit the fabrication instructions in terms of the original system of coordinates as provided by the computer object data, in which case the transformation of coordinates is executed by the circuit of controller 20.

The transformation of coordinates allows three-dimensional printing over a rotating tray. In non-rotary systems with a stationary tray with the printing heads typically reciprocally move above the stationary tray along straight lines. In such systems, the printing resolution is the same at any point over the tray, provided the dispensing rates of the heads are uniform. In system 10, unlike non-rotary systems, not all the nozzles of the head points cover the same distance over tray 12 during at the same time. The transformation of coordinates is optionally and preferably executed so as to ensure equal amounts of excess material formulation at different radial positions. Representative examples of coordinate transformations according to some embodiments of the present invention are provided in FIGs. 3A-B, showing three slices of an object (each slice corresponds to fabrication instructions of a different layer of the objects), where FIG. 3A illustrates a slice in a Cartesian system of coordinates and FIG. 3B illustrates the same slice following an application of a transformation of coordinates procedure to the respective slice.

Typically, controller 20 controls the voltage applied to the respective component of the system 10 based on the fabrication instructions and based on the stored program instructions as described below.

Generally, controller 20 controls printing heads 16 to dispense, during the rotation of tray 12, droplets of building material formulation in layers, such as to print a three-dimensional object on tray 12.

System 10 optionally and preferably comprises one or more radiation sources 18, which can be, for example, an ultraviolet or visible or infrared lamp, or other sources of electromagnetic radiation, or electron beam source, depending on the modeling material formulation being used. Radiation source can include any type of radiation emitting device, including, without limitation, light emitting diode (LED), digital light processing (DLP) system, resistive lamp and the like. Radiation source 18 serves for curing or solidifying the modeling material formulation. In various exemplary embodiments of the invention the operation of radiation source 18 is controlled by controller 20 which may activate and deactivate radiation source 18 and may optionally also control the amount of radiation generated by radiation source 18.

In some embodiments of the invention, system 10 further comprises one or more leveling devices 32 which can be manufactured as a roller or a blade. Leveling device 32 serves to straighten the newly formed layer prior to the formation of the successive layer thereon. In some embodiments, leveling device 32 has the shape of a conical roller positioned such that its symmetry axis 34 is tilted relative to the surface of tray 12 and its surface is parallel to the surface of the tray. This embodiment is illustrated in the side view of system 10 (FIG. 1C).

The conical roller can have the shape of a cone or a conical frustum.

The opening angle of the conical roller is preferably selected such that there is a constant ratio between the radius of the cone at any location along its axis 34 and the distance between that location and axis 14. This embodiment allows roller 32 to efficiently level the layers, since while the roller rotates, any point p on the surface of the roller has a linear velocity which is proportional (e.g., the same) to the linear velocity of the tray at a point vertically beneath point p. In some embodiments, the roller has a shape of a conical frustum having a height h, a radius Ri at its closest distance from axis 14, and a radius R2 at its farthest distance from axis 14, wherein the parameters h, R\ and R satisfy the relation R IR2=(R-h)lh and wherein R is the farthest distance of the roller from axis 14 (for example, R can be the radius of tray 12).

The operation of leveling device 32 is optionally and preferably controlled by controller 20 which may activate and deactivate leveling device 32 and may optionally also control its position along a vertical direction (parallel to axis 14) and/or a radial direction (parallel to tray 12 and pointing toward or away from axis 14.

In some embodiments of the present invention printing heads 16 are configured to reciprocally move relative to tray along the radial direction r. These embodiments are useful when the lengths of the nozzle arrays 22 of heads 16 are shorter than the width along the radial direction of the working area 26 on tray 12. The motion of heads 16 along the radial direction is optionally and preferably controlled by controller 20.

Some embodiments contemplate the fabrication of an object by dispensing different material formulations from different arrays of nozzles (belonging to the same or different printing head). These embodiments provide, inter alia, the ability to select material formulations from a given number of material formulations and define desired combinations of the selected material formulations and their properties. According to the present embodiments, the spatial locations of the deposition of each material formulation with the layer is defined, either to effect occupation of different three-dimensional spatial locations by different material formulations, or to effect occupation of substantially the same three-dimensional location or adjacent three-dimensional locations by two or more different material formulations so as to allow post deposition spatial combination of the material formulations within the layer, thereby to form a composite material formulation at the respective location or locations.

Any post deposition combination or mix of modeling material formulations is contemplated. For example, once a certain material formulation is dispensed it may preserve its original properties. However, when it is dispensed simultaneously with another modeling material formulation or other dispensed material formulations which are dispensed at the same or nearby locations, a composite material formulation having a different property or properties to the dispensed material formulations may be formed.

In some embodiments of the present invention the system operates to form inkjet-printed digital material for at least one region in the object.

The phrase “inkjet-printed digital material”, abbreviated below as "digital material," as used herein and in the art, describes a combination of two or more materials on a pixel level or voxel level such that pixels or voxels of different material formulations are interlaced with one another over a region. Such digital materials may exhibit new properties that are affected by the selection of types of material formulations and/or the ratio and relative spatial distribution of two or more material formulations.

As used herein, a "voxel" of a layer refers to a physical three-dimensional elementary volume within the layer that corresponds to a single pixel of a bitmap describing the layer. The size of a voxel is approximately the size of a region that is formed by a building material, once the building material is dispensed at a location corresponding to the respective pixel, leveled, and solidified.

In the context of a digital material, the interlacing can be either among single voxels, each containing a different building material, or among blocks of voxels wherein a block of voxels is defined as a continues region that is occupied by n voxels all containing the same building material, and wherein the border of this region is define as a collection of voxels that are adjacent to at least one voxel that contains a building material other than the building material contained in the voxels of the collection. In preferred embodiments, n is less than 1000, or less than 500, or less than 100, or less than 50, or less than 10.

In exemplary digital materials, the modeling material of each voxel or voxel block, obtained upon curing, is independent of the modeling material of a neighboring voxel or voxel block, obtained upon curing, such that each voxel or voxel block may result in a different model material and the new properties of the whole part are a result of a spatial combination, on the voxel level, of several different model materials.

The present embodiments thus enable the deposition of a broad range of material formulation combinations, and the fabrication of an object which may consist of multiple different combinations of material formulations, in different parts of the object, according to the properties desired to characterize each part of the object.

Further details on the principles and operations of an AM system suitable for the present embodiments are found in U.S. Patent No. 9,031,680, the contents of which are hereby incorporated by reference.

The Inventor found that objects manufactured by AM often present challenges in handling and care after the AM stage of (e.g., post process stages), attributed to their intricate designs, fragility, and specific post processing requirements. Handling difficulties are posed also in cases of small-size objects (on a millimeter or centimeter scale). For example, the structure of an object might contain intricate geometries and fine details or be very small and delicate, making it susceptible to damage or deformation if mishandled. Certain objects manufactured by AM require application of one or more post- AM processes, such as, but not limited to, waterjet, sand blasting, rotary tumbling, vibratory tumbling, burnishing, sanding, magnetic pin finishing, spray coating, dipping, coating (e.g., epoxy coating), plating (e.g., electroplating), heat and/or UV curing, and drying. The Inventors found that post- AM processes may pose challenges, especially concerning processes that require application from all sides or angles of the object.

In a search for overcoming the above challenges, the Inventor devised a technique that allows more convenient and oftentimes also cautious handling of object manufactured by AM often while preserving their structural integrity and allowing them to be processed post manufacturing.

FIGs. 4A and 4B are schematic illustrations of a hangable object assembly 400, according to some embodiments of the present invention. Object assembly 400 comprises a first plurality 402 of layers 404 formed by additive manufacturing and defining a three-dimensional object 414, and a second plurality 406 of layers 408 formed by additive manufacturing and defining a three- dimensional hangable element 410. First 402 and second 406 pluralities of layers can be manufactured by any AM technology known in the art, including, without limitation, three-dimensional printing, three-dimensional inkjet printing (e.g., Stratasys™ PolyJet™ technology), fused deposition modeling (FDM), selective laser sintering (SLS), powder bed fusion (PBF), stereolithography (SLA), powder binding, electron-beam melting, electrophotographic imaging, digital light processing (DLP) and LED based vat processing. In some embodiments of the present invention first 402 and second 406 pluralities of layers are manufactured by the same AM technology and in some embodiments of the present invention first 402 and second 406 pluralities of layers are manufactured by different AM technologies. Preferably, but not necessarily, one of first 402 and second 406 pluralities of layers or both first 402 and second 406 pluralities of layers are manufactured by three-dimensional printing, more preferably three-dimensional inkjet printing using inkjet dispensing heads as further detailed hereinabove.

In some embodiments of the present invention hangable element 410 detachably protrudes out of an outer surface 412 of object 414 and a protruding location 438. For clarity of presentation, the individual layers 404 and 408 are only illustrated in FIGs. 4A-B. It is appreciated that object 414 can have any shape and that the shape shown in FIGs. 4A-B for object 414 is not to be considered as limiting. In particular, outer surface 412 need not be planar. Further, although hangable element 410 is shown to protrude out perpendicularly to the layers of the object, this need not necessarily be the case since in some cases it is more convenient to manufacture hangable element 410 in a manner that it does not protrude out perpendicularly to the layers. For example, hangable element 410 can protrude out at an acute angle to the layers, or it can protrude out parallel to the layers, e.g., out of side surface 413 of object 414. Preferably, but not necessarily, layers 408 of element 410 are parallel to layers 404 of object 414.

In some embodiments of the present invention two or more of the layers 408 of hangable element 410 are leveled with respective to two or more of layers 404, so that hangable element comprises an internal portion 422 that is embedded within object 414. Such a configuration is optionally and preferably achieved by forming the second optionally and preferably layers together with the first plurality of layers. The internal portion 422 can in some embodiments of the present invention be tapered, as illustrated in FIG. 4A, or it can be flared inwardly into object 414, as illustrated in FIG. 4B. Alternatively, hangable element 410 can be formed such that all the layers 408 are external to object 414.

Magnified views of hangable element 410 according to some embodiments of the present invention are illustrated in FIGs. 5A-H. Preferably, hangable element 410 comprises a breakable portion 416 adjacent to outer surface 412 of object 414. Breakable portion 416 is optionally and preferably tapered, with a diameter that decreases toward outer surface 412. In some embodiments of the present invention breakable portion 416 comprises air voids 418 to allow it to break more easily than other parts of element 410. Also contemplated, are embodiments in which the material from which breakable portion 416 is fabricated is different (e.g., more brittle) than the material of other portions of hangable element 410. When hangable element 410 is manufactured by inkjet printing, breakable portion 416 can comprise an inkjet-printed digital material, in which different building materials are interlaced with each other over breakable portion 416. The building materials that form the digital material are preferably selected such that the breakability of portion 416 is higher than the breakability of other portions of element 410. For example, the digital material can include voxels of material A interlaced with voxels of material B, where material A is more rigid than material B. The digital material can optionally and preferably comprise support material voxels.

With reference to FIG. 5E, detachment of hangable element 410 can also be by peeling. In these embodiments, hangable element 410 comprises a peelable portion 420 adjacent to outer surface 412. When a peeling force is applied to peelable portion 420 in the direction shown by the arrow in FIG, 5E, hangable element 410 is detached from surface 412. The magnitude of the peeling force can be from about 1 N to about 20 N, e.g., about 5N or about 10 N or about 15 N. In embodiments in which hangable element 410 comprises peelable portion 420, at least a portion of peelable portion 420 is made of an elastomeric material.

The phrase “elastomeric material” describes a solidifiable (e.g., curable) material, which following a solidification (for example, upon exposure to energy, such as, but not limited to, curing energy) acquires properties of an elastomer (a rubber, or rubber-like material). Representative examples of materials suitable for use in the peelable portion 420 are described in international publication number WO2017208238, the contents of which are hereby incorporated by reference.

Detachment of hangable element 410 can also be by operating a tool such as a cutter, scissors, pliers, a knife, a chisel, and the like for detaching the hangable element from the object 414. Combinations of two or more of the above detachment techniques are also contemplated according to some embodiments of the present invention.

A distal end 424 of hangable element 410 with respect to outer surface 412 of object 414 is optionally and preferably shaped to form a connecting member 426. FIGs. 4A-B and 5B-E illustrate an embodiment in which connecting member 426 is shaped as an eyelet. FIG. 5A illustrate an embodiment in which connecting member 426 is shaped as a hook, and FIGs. 5F-H illustrate an embodiment in which connecting member 426 is a male connector. Also contemplated are embodiment in which connecting member 426 is a female connector. It is to be understood that connecting member 426 can have any shape that allows it to connect to an immobilized structure, such as, but not limited to, a wire, a matching hanger, a matching hook, and the like, irrespective of the mechanism that allows the detachment of element 410 from 412. For example, connecting member 426 can be shaped as an eyelet also when element 410 comprises breakable portion 416 with air voids 418, or be a male or female connector or a hook also when element 410 comprises peelable portion 420.

FIGs. 6A-F illustrate representative examples of shapes and sizes for an immobilized structure 428 to which connecting member 426 can connect according to some embodiments of the present invention. FIGs. 6A-D illustrate embodiments in which immobilized structure 428 is a female hanger matching connecting member 426 when connecting member 426 is embodied as a male connector, FIG. 6E illustrates an embodiment in which immobilized structure 428 is a wire, and FIG. 6F illustrates an embodiment in which immobilized structure 428 is a hook. Also contemplated, are embodiments in which immobilized structure 428 is a male hanger matching connecting member 426 when connecting member 426 is embodied as a female connector.

Before detaching hangable element 410 from object 414, connecting member 426 is connected to immobilized structure 428, thus forming together an object assembly including object 414, connecting member 426, and immobilized structure 428.

The shape and size of connecting member 426 and immobilized structure 428 are preferably selected conjointly to ensure size-wise and shape-wise matching therebetween so as to allow them to connect. Thus, connecting member 426 and immobilized structure 428 can be selected to be a connector and matching hanger that allows a male-female connection relation, or they can be selected as an eyelet and a wire or a hook wherein the eyelet is sized to allow it to receive the wire or the hook, or they can be selected as a hook and a wire wherein the hook is sized to hang on the wire, or they can be selected as a pair of hooks hangable on each other, etc.

In some embodiments of the present invention the connecting member 426 is manufactured by AM. These embodiments are particularly useful when a precise matching between connecting member 426 and immobilized structure 428 is required, for example, in cases of a connector matching a hanger in a male-female connection relation.

In some embodiments of the present invention hangable element 410 comprises an identifiable pattern 432 on an outer surface 430 of hangable element 410, see FIGs. 5F-5H. It is to be understood that although identifiable pattern 432 is only shown in FIGs. 5F-H, the present embodiments contemplate a hangable element with an identifiable pattern irrespective of the shape and detachment mechanism selected for the hangable element. Further, it is to be understood that pattern 432 is shown as a relief pattern in the form of one or more bands surrounding the outer surface 430 of element 410, while the present embodiments contemplate any type of pattern (relief, intaglio, or two-dimensional) having any shape, indicia and/or color. Pattern 432 serves to allow the user to identify hangable element 410 and hence also to identify object 414 that is connected thereto. The advantage of this embodiment is that when it is employed there is no need to add an identifying feature to the object itself in order to distinguish it from other objects manufactured in the same facility or during the same AM batch.

Pattern 432 can be used in more than one way. In some embodiments of the present invention, pattern 432 is user specific. These embodiments are particularly useful in cases in which several users operate AM system(s) within the same facility and it is desired to associate each manufactured object with the user that operated the AM system that produced it.

In some embodiments of the present invention pattern 432 is hanger specific. These embodiments can be employed when connecting member 426 and immobilized structure 428 are a connector and matching hanger, and are particularly useful in cases in which a facility has several lookalike hangers since they allow selecting the appropriate hanger for a particular hangable element without the need to execute a trial- and-error operation, an advantage in cases in which the object is small, delicate, and/or fragile. In these embodiments, the hanger optionally and preferably has the same identifiable pattern on its outer surface. Representative examples are illustrated in FIGs. 5F-H and 6A-D, wherein the connector of the hangable element of FIG. 5F matches the hangers of FIGs. 6A and 6B (a single-band relief pattern), the connector of the hangable element of FIG. 5G matches the hanger of FIG. 6C (a double-band relief pattern), and the connector of the hangable element of FIG. 5H matches the hanger of FIG. 6D (a three-band relief pattern).

In some embodiments of the present invention, pattern 432 comprises a scannable tag (e.g., a barcode, a QR code, etc.) which optionally and preferably encodes post-AM related data, such as post-process stages and order of their execution. The scannable tag may be either manufactured by AM as part of hangable element 410 or added after hangable element 410 is manufactured by AM (e.g., in the form of a sticker).

Pattern 432 can encode instructions regarding required application of one or more post-AM processes. For example, a first unique pattern can encode instructions to execute a first type of post-AM process, a second unique pattern can encode instructions to execute a second type of post- AM process, a third unique pattern can encode instructions to execute the first type of post-AM process and then the second type of post-AM process, and a fourth unique pattern can encode instructions to execute the second type of post-AM process and then the first type of post-AM process.

Unique patterns for executing more than one type of post-AM process, can be combinations of unique patterns that encode instructions to execute each individual post-AM process. For example, suppose that the aforementioned first unique pattern is a relief pattern having a shape of a band and a first specific color, and that the aforementioned second unique pattern is a relief pattern also having the shape of a band but with a second specific color. In this case, the aforementioned third unique pattern can be a double-band relief pattern in which the upper band has the first specific color and the lower band has the second specific color, and the aforementioned fourth unique pattern can also be a double-band relief pattern in which the upper band has the second specific color and the lower band has the first specific color.

The present embodiments contemplate encoding in pattern 432 instructions regarding any type of post-AM process, including, without limitation, an instruction to execute water jetting, an instruction to execute sand blasting, an instruction to execute rotary tumbling, an instruction to execute vibratory tumbling, an instruction to execute burnishing, an instruction to execute sanding, an instruction to execute magnetic pin finishing, an instruction to execute spray coating, an instruction to execute dipping, an instruction to execute coating (e.g., epoxy coating), and an instruction to execute plating (e.g., electroplating).

Any two or more of the above uses of pattern 432 can be combined. Specifically, pattern 432 can be user specific and also encode instructions regarding one or more post-AM processes, or be hanger specific and also encode instructions regarding one or more post-AM processes, or be user specific and also be hanger specific, or be user specific and also be hanger specific and also encode instructions regarding one or more post-AM processes.

Hangable element 410 can be made of any building material suitable for AM. The material of element 410 can be the same of the material from which object 414 is made, or, in case in which object 414 is a multi-material object (an object that us made of more than one building material), element 410 can be made of one of the materials from which object 414 is made. Alternatively, hangable element 410 can be made of a material that is different from the material or different from any of the materials from which object 414 is made. Also contemplated, are embodiments in which hangable element 410 is by itself a multi-material object, wherein one or more of the building materials from which hangable element 410 can be the same or different from the building materials from which object 414 is made. FIGs. 7A and 7B are schematic illustrations of hangable element 410 in embodiments of the present invention in which the rigidity of hangable element 410 increases away from object 414. The direction along which the rigidity is increased is represented in FIGs. 7C and 7D as a block arrow and the rigidity level is represented by the gray level of element 410. These embodiments are particularly useful objects that comprise a flexible material at the interface with hangable element 410. Making the portion of element 410 that interfaces object 414 flexible to facilitates easy detachment of object 410, and making the portion of element 410 that is further away from object 410 rigid, facilitates connecting element to the immobilized structure (not shown in FIGs. 7A and 7B, see FIGs. 6A-F).

FIGs. 7C and 7D are schematic illustrations of hangable element 410 in embodiments of the present invention in which hangable element 410 comprises a core 434 and a coating 436 at least partially surrounding core 434. In some embodiments of the present invention core 434 is more rigid than coating 436. These embodiments are particularly useful for relatively heavy objects that comprise a flexible material at the interface with hangable element 410. The Inventor found that such a structure for element 410 strengthens element 410 in terms of higher tear resistance.

The difference between FIGs. 7 A and 7B and between FIGs. 7C and 7D is that in FIGs. 7 A and 7C internal portion 422 of element 410 is tapered and in FIGs. 7B and 7D internal portion 422 of element 410 flares inwardly into object 414.

FIG. 8 is a flowchart diagram of a method suitable for additive manufacturing, of a three- dimensional object in layers, according to various exemplary embodiments of the present invention. It is to be understood that, unless otherwise defined, the operations described hereinbelow can be executed either contemporaneously or sequentially in many combinations or orders of execution. Specifically, the ordering of the flowchart diagrams is not to be considered as limiting. For example, two or more operations, appearing in the following description or in the flowchart diagrams in a particular order, can be executed in a different order (e.g., a reverse order) or substantially contemporaneously. Additionally, several operations described below are optional and may not be executed.

The method begins at 800 and proceeds to 801 at which computer object data of a three- dimensional object, such as, but not limited to, object 414 is loaded to a computer. The computer object data is typically in the form of graphic elements (e.g., a mesh of polygons, non-uniform rational basis splines, etc.) defining a surface of the object.

In some embodiments of the present invention the method proceeds to 802 at which the expected mass and/or volume of the object is calculated based on the data loaded at 801. The volume can be calculated by analyzing the graphic elements that form the data. The mass can be calculated based on the graphic elements that form the data as well as the density of the material or materials from which the object is to be manufactured.

In some embodiments of the present invention the method proceeds to 803 at which center- of-mass of the object is calculated. This can be done based on the data loaded at 801 and, when it is desired to manufacture a multi-material object, also based on the density of the materials from which the object is to be manufactured.

At 805 a protruding location is optionally and preferably selected for a hangable element, such as, but not limited to, element 410, and at 806 a size and/or a shape of the hangable element and/or the depth by which the hangable element penetrates into the object is selected. The protruding location is preferably selected automatically, typically based on the calculated center- of-mass. For example, the method can select, or receive as input, an orientation that the object would assume once hung, and then select a protruding location that is directly above the center-of- mass with respect to gravity for that orientation. The size and/or shape and/or depth can also be selected automatically, for example, based on the expected mass of the object, wherein larger and more stable shapes and deeper penetration depths are selected for heavier objects. For example, the hangable element shown in FIG. 5B or 5H can be selected for a heavier object and the hangable element shown in FIG. 5D or 5F can be selected for a less heavy object. In some embodiments of the present invention the method displays 804 a graphical user interface (GUI), for allowing the user to force a specific selection of the protruding location, size, and/or shape of the hangable element. Some embodiments of the present invention also encompass an option for selecting (either automatically, semi-automatically or manually) a plurality (two or more) of protruding locations and optionally one or more size and/or shapes and/or material composition of an hangable element at said protruding locations. This may be particularly advantageous with complex shapes of 3D printed objects and/or if some distinct post- AM stages require distinct spatial orientations of the 3D printed object.

The GUI includes a plurality of computer-generated objects, which are referred to as "GUI controls", or in more abbreviated term "controls." Representative examples of GUI controls suitable for the present embodiments include, without limitation, a slider, a dropdown menu, a combo box, a text box and the like.

The GUI controls are responsive to physical operations performed by the user by means of devices that communicate signals to the computer. Such devices can be a computer mouse, a touch screen, a keyboard or the like, and may optionally include a microphone in which case the computer is configured to execute voice-activated software. The GUI can optionally and preferably display additional information, such as non-interactive text and graphics.

During operation, the end-user can select and activate the controls in order to initiate operations to be executed by the processor of the computer. The GUI transmits activation signals to the processor, for example, by means of an I/O circuit configured to communicate signals between the GUI and the processor. The activation signals can be transmitted to the processor either upon activation of the respective control, or at a later time (e.g., upon activation of another control). The controls are represented on the GUI as graphical elements that are optionally and preferably labeled in a manner that is indicative of the operation that the processor executes responsively to the activation of these controls. The controls may be arranged in predefined layouts, or may be created and/or removed dynamically responsively to specific actions being taken by the end-user by means of other GUI controls. By way of example, a user may select a button that opens or closes another control, expands a control, displays an image, and/or switches between GUI layouts (oftentimes referred to as GUI screens).

The GUI of the present embodiments receives from the end-user, by means of the GUI controls, input pertaining to the protruding location, size, and/or shape of the hangable element. Responsively to activation of one or more of the GUI controls, the I/O circuit of the computer communicates signals pertaining to this input from the GUI to the processor, and the processor converts those signals to digital design data allowing the processor to select the protruding location, size, and/or shape of the hangable element.

A representative example of a GUI 900 suitable for the present embodiments is illustrated in FIG. 9. GUI 900 can comprise a hangable element type selection control 902 allowing the user to select a type from a list of shapes suggested by the GUI. Control 902 can also allow the user to load a shape for the hangable element from an external file or allow the user to create a shape by a drawing tool or the like. Control 902 can in some embodiments of the present invention allow the user to select two or more hangable elements of different or the same types, in cases in which it is desired to hang the object by means of more than one hangable element. These embodiments are useful for heady and/or large objects that cannot be supported by a single hangable element.

GUI 900 can also comprise a hangable element size selection control 904 allowing the user to select the size of the selected type. Control 904 can provide a list of sizes from which the size can be selected, or allow entering the size numerically. GUI 900 can also comprise a pattern type selection control 906 allowing the user to select a pattern (such as, but not limited to, pattern 432) to be formed on the outer surface of the hangable element, and a pattern property (e.g., color) selection control 908 allowing the user to select a property or properties (e.g., color or colors) of the selected pattern. GUI 900 can also comprise a penetration depth selection control 912 allowing the user to select the depth by which the hangable element penetrates into the object to form the internal region 422.

GUI 900 can further comprise a visualization area 914 at which GUI 900 displays the object 414 and the hangable element 410 connected thereto. GUI 900 can comprise a protruding location control 910 allowing the user to select the location of the interface between the object and the hangable element (or locations of two or more such interfaces in case in which two or more hangable elements are selected). Conveniently, the control 910 can be in the form of a symbol that is movable over the outer surface of the object 414 displayed at area 914, but other types of controls can also be used. Preferably, the computer calculates a hanging orientation by which the object 414 would be oriented once hanged by means of element 410, and GUI 900 orients or re-orients the image of object 414 at area 914 based on the calculated orientation. GUI 900 can comprise an orientation variation control 916 allowing the user to vary the orientation of object 414. In these embodiments, the computer calculates the protruding location that would provide the orientation displayed on area 910, for example, based on the calculated center-of mass, and suggest this protruding location, for example, by displacing it on area 914. Control 916 can be either an alternative to control 910 or be provided therewith. Also contemplated are embodiments in which none of these controls is provided by GUI 900, in which case the protruding location can be a predefined default location.

Preferably, GUI 900 comprises a material information area 924 that displays the types of building materials that are to be used for manufacturing the object 414. The materials in area 924 allow the computer to suggest recommended states for the various controls. For example, based on these materials GUI 900 can suggest recommended property (e.g., color and/or shape) for the pattern 432. Also, based on these materials the computer can perform the calculations at 802 and 803, and GUI 900 can suggest a recommended size and or shape for the hangable element and/or a recommended protruding location and/or recommended penetration depth.

Referring again to FIG. 8, the method proceeds to 807 at which computer object data of the hangable element are loaded to the computer. The computer object data is typically in the form of graphic elements defining a surface of the hangable element, and are optionally and preferably based on the size and shape selected at 806, either automatically or by means of GUI 900. Practically, a computer readable medium can store several files with computer object data of different types and/or sizes of hangable elements, and the method can select the file based on the selected size and shape.

The method proceeds to 808 at which the computer object data of the object and hangable element are combined. The combination is executed to ensure that the location at which hangable element interfaces the object is according to the protruding location and penetration depth, wherein each of the protruding location and penetration depth can independently be predetermined, calculated, or selected by means of GUI 900. It is appreciated that when combining the two computer object data, some geometrical issues may arise in regions in with there is a spatial overlap between the object and the hangable element. In this case, priority in the combined data is optionally and preferably given to data describing the object over data describing the hangable element.

The method optionally and preferably proceeds to 809 at which the combined computer object data are sliced by the computer running slicer software to provide slice data describing a plurality of slices, each defined over a plurality of voxels, and describing one of the layers of the object or one of the layers of the hangable element. The slicing operation preferably assigns to each voxel of each slice, a building material.

The method proceeds to 810 at which the slice data are transmitted to an AM system to form a first plurality of layers in configured patterns corresponding to shapes of slices of the object, and a second plurality of layers in configured patterns corresponding to shapes of slices of the hangable element. In some embodiments of the present invention the second plurality of layers are made of a curable material, and the AM system cures the second plurality of layers in a manner that an extent of the curing is higher at the breakable portion of the hangable element than at other portions of the hangable element, thus making the hangable element more brittle at the breakable portion. The AM system can optionally and preferably also dispense one or more building material formulations to form a sacrificial structure that serves as a support structure for one or more surfaces of the object and/or the hangable element, or as a filler for filling hollow parts of the object and/or the hangable element during the AM process. The building material formulations that are dispensed for the fabrication of the sacrificial structure typically comprise at least one support material formulation.

In some embodiments of the present invention the method proceeds to 811 at which computer object data of a hanger are loaded to the computer. The computer object data of the hanger are optionally and preferably based on the size and shape of the hangable element. The computer object data of the hanger are sliced 812 and the slice data are transmitted 813 to an AM system to form the hanger. The AM system can optionally and preferably also dispense one or more building material formulations to form a sacrificial structure that serves as a support structure for one or more surfaces of the hanger, or as a filler for filling hollow parts of the hanger. The building material formulations that are dispensed for the fabrication of the sacrificial structure for the hanger typically comprise at least one support material formulation. It is appreciated that a hanger can be used repeatedly and so in some embodiments of the present invention the method forms a plurality of object assemblies for each hanger. When a sacrificial structure is formed at 810 and/or at 813 the method optionally and preferably proceed to 814 at which the sacrificial structure is removed. The removal, can be by applying a jet of liquid (e.g., aqueous liquid, such as, but not limited to, water), and/or by peeling, and/or by breaking, depending on the nature and type of materials, and particularly, but not necessarily exclusively, the type of support material, used for fabricating the respective sacrificial structure.

At 815 the hangable element of the object assembly is hung on a suitable immobilized structure. The immobilized structure can be any of the structures 428 shown in FIGs. 6A-F. In embodiments in which 811-813 are executed the immobilized structure can be the hanger. At 816 a post-AM process is applied to the hangable object assembly, wherein the post-AM process can be any of the aforementioned types of post-AM processes. Preferably, at least one of a type and a protocol of the post-AM process is selected based on the identifiable pattern, as further detailed hereinabove. At 817 the hangable element is detached from the object e.g., by breaking the breakable portion and/or by peeling the peelable portion, and/or by operating a tool such as a cutter, scissors, pliers, a knife, a chisel, and the like for detaching the hangable element from the object.

The method ends at 818.

The terms "comprises", "comprising", "includes", "including", “having” and their conjugates mean "including but not limited to".

The term “consisting of’ means “including and limited to”.

The term "consisting essentially of" means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure.

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof. Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases “ranging/ranges between” a first indicate number and a second indicate number and “ranging/ranges from” a first indicate number “to” a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below find experimental support in the following examples.

EXAMPLES

Reference is now made to the following examples, which together with the above descriptions illustrate some embodiments of the invention in a non limiting fashion.

Table 1 below, lists types and sizes of hangable elements 410, together with preferred diameters of the element at the protruding location and preferred penetration depths. In the table, three sizes of hangable element (referred to as large, medium and small), and two types of connecting members (eyelet see FIGs. 5B-D, and connector see FIGs. 5F-H) are considered. Table 1

Table 2 below, lists colors for pattern 432 that can be suggested as recommended for various colorings of the outer surface 430 of the hangable element 410. The colors listed in each row of the rightmost column of Table 2, are ordered according to their selection priorities, where the leftmost color in each list in the rightmost column has the highest priority to be selected according to a preferred embodiment of the present invention.

Table 2

Experiments were performed to ensure stability of the connection between the object and the hangable element. In an exemplified experiment, a hangable element in the small class (see table 1) and a connecting member in the form of a connector were printed by three-dimensional inkjet printing together with an object being in the form of a figurine, 30 mm in length. In another exemplified experiment, a hangable element in the large class (see table 1) and a connecting member in the form of a connector were printed by three-dimensional inkjet printing together with an object being in the form of a 2 liter bottle (more than 2Kg in weight). In all experiments, the formed object assembly was hung on a wire, and the stability of the connection of the object to the hangable element was observed for at least 3 consecutive days.

FIG. 10 is an image of an object assembly, manufactured by three-dimensional inkjet printing according to some embodiments of the present invention, and including object 414, hangable element 410 comprising relief pattern 432 and breakable portion 416, and hanger 428, wherein hangable element 410 protrudes out of object 414, connector 426 of hangable element 410 is connected by a male-female connection to hanger 428, and hanger 428 is itself hung on a wire 440.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

It is the intent of the applicant(s) that all publications, patents and patent applications referred to in this specification are to be incorporated in their entirety by reference into the specification, as if each individual publication, patent or patent application was specifically and individually noted when referenced that it is to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting. In addition, any priority document(s) of this application is/are hereby incorporated herein by reference in its/their entirety.

Claims

WHAT IS CLAIMED IS:

1. A hangable object assembly, comprising: a first plurality of layers formed by additive manufacturing and defining a three- dimensional object; and a second plurality of layers formed by additive manufacturing and defining a three- dimensional hangable element detachably protruding out of an outer surface of said object.

2. A method of additive manufacturing comprising: forming by additive manufacturing a first plurality of layers in configured patterns corresponding to shapes of slices of a three-dimensional object; and forming by additive manufacturing a second plurality of layers in configured patterns corresponding to shapes of slices of a three-dimensional hangable element detachably protruding out of an outer surface of said object, thereby manufacturing a hangable object assembly.

3. The hangable object assembly or method according to any of claims 1 and 2, wherein said hangable element comprises a breakable portion adjacent to said outer surface of said object.

4. The hangable object assembly or method according to claim 3, wherein said breakable portion is tapered.

5. The hangable object assembly or method according to any of claims 3 and 4, wherein said breakable portion comprises air voids.

6. The hangable object assembly or method according to any of claims 3-5, wherein a material of said breakable portion is different than a material of other portions of said hangable element.

7. The hangable object assembly or method according to any of claims 3-6, wherein said additive manufacturing is inkjet printing, and wherein said breakable portion comprises an inkjet-printed digital material.

8. The hangable object assembly or method according to any of claims 1 and 2, wherein said hangable element comprises a peelable portion adjacent to said outer surface of said object.

9. The hangable object assembly or method according to any of claims 1-8, wherein a portion of said second plurality of layers is formed together with a portion of said first plurality of layers to form an internal portion of said hangable element that is embedded within said object.

10. The hangable object assembly or method according to claim 9, wherein said internal portion of said hangable element has a tapered or a flared shape.

11. The hangable object assembly or method according to any of claims 1-10, wherein a distal end of said hangable element with respect to said outer surface of said object is shaped to form a connecting member.

12. The hangable object assembly or method according to claim 11, wherein said distal end is shaped as a hook or an eyelet.

13. The hangable object assembly or method according to claim 11, wherein said connecting member is a connector shaped and sized to match a hanger in a male-female connection relation.

14. The hangable object assembly or method according to any of claims 1-13, wherein said hangable element comprises an identifiable pattern on an outer surface of said hangable element.

15. The hangable object assembly or method according to claim 13, wherein said hangable element comprises an identifiable pattern on an outer surface of said hangable element, and wherein said hanger also has said identifiable pattern on an outer surface of said hanger.

16. The hangable object assembly or method according to any of claims 14-15, wherein said identifiable pattern is user- specific.

17. The hangable object assembly or method according to any of claims 1-16, wherein said hangable element comprises a core and a coating, and wherein said core is more rigid than said coating.

18. The hangable object assembly or method according to any of claims 1-17, wherein a rigidity of said hangable element increases gradually away from said object.

19. The hangable object assembly or method according to any of claims 1-18, wherein said first and said second pluralities of layers are formed by the same additive manufacturing technology.

20. The hangable object assembly or method according to any of claims 1-18, wherein said first and said second pluralities of layers are formed by different additive manufacturing technology.

21. The hangable object assembly or method according to any of claims 1-18, wherein at least one of said first and said second pluralities of layers are formed by inkjet printing.

22. The method according to claim 13, comprising manufacturing said hanger by additive manufacturing.

23. The method according to claim 22, comprising manufacturing a plurality of hangable object assemblies each having a connector shaped and sized to match said hanger in a male-female connection relation.

24. The method according to any of claims 2-23, comprising applying a post additive manufacturing process to said hangable object assembly, and detaching said hangable element from said object following said application of said post additive manufacturing process.

25. The method according to any of claims 2-24, wherein said second plurality of layers are made of a curable material, and the method comprising curing said second plurality of layers in a manner that an extent of said curing is higher at said breakable portion than at other portions.

26. The method according to claim 14, comprising automatically selecting at least one property of said pattern based on a material from which said hangable element is formed.

27. The method according to any of claims 14-15, comprising applying a post additive manufacturing process to said hangable object assembly, wherein at least one of a type and a protocol of said post additive manufacturing process is selected based on said identifiable pattern.

28. The method according to any of claims 2-27, comprising calculating an expected mass and/or volume of said object, and automatically selecting at least one of a size and a shape of said hangable element based on said calculated mass and/or volume.

29. The method according to any of claims 2-28, wherein said hangable element protrudes out of said outer surface of said object at a protruding location over said surface, and the method comprises calculating an expected a center-of-mass of said object, and automatically selecting said protruding location based on said calculated center-of-mass.

30. The method according to any of claims 2-29, comprising, prior to said forming said first and said second pluralities of layers: displaying a graphical user interface (GUI) having a protruding location control, for allowing a user to select a protruding location over said outer surface of said object at which said hangable element protrudes out of said surface; receiving protruding location input from said protruding location control; and displaying on said GUI an expected hanging orientation of said hangable object assembly responsively to said input.

31. The hangable object assembly according to claim 13, comprising said hanger.

32. A computerized controller for an additive manufacturing system, the computerized controller comprising a circuit configured for operating the additive manufacturing system to execute the method according to any of claims 2-23, 25-26, and 28-30.

33. An additive manufacturing system comprising a dispensing head, a working surface and the computerized controller of claim 32.