WO2021211096A1

WO2021211096A1 - Additively manufacturing a lattice structure including a separable portion

Info

Publication number: WO2021211096A1
Application number: PCT/US2020/028089
Authority: WO
Inventors: Wei Huang; David C. WOODLOCK; Gary J. Dispoto
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2020-04-14
Filing date: 2020-04-14
Publication date: 2021-10-21

Abstract

A device to additively manufacture a first 3D object comprises at least a first portion defining a lattice structure of elements. The lattice structure includes a separation path extending at least partially within an interior portion of the lattice structure and the separation path includes a first release boundary extending through some of the elements along the separation path.

Description

ADDITIVELY MANUFACTURING A LATTICE STRUCTURE INCLUDING A SEPARABLE PORTION

Background

[0001] Additive manufacturing may revolutionize design and manufacturing in producing three-dimensional (3D) objects. Some forms of additive manufacturing may sometimes be referred to as 3D printing, and may produce 3D objects with complex attributes.

Brief Description of the Drawings

[0002] FIG. 1 is a diagram schematically representing an example device and/or example method of additively manufacturing an example 3D object.

[0003] FIG. 2 is a diagram including a front elevational view schematically representing at least a portion of an example 3D object including an example lattice structure.

[0004] FIG. 3 is a diagram including a front elevational view schematically representing at a portion separated from the example lattice structure of the example 3D object of FIG. 2.

[0005] FIG. 4 is a block diagram and an isometric view schematically representing an example device and/or example method to additively manufacture a 3D object. [0006] FIG. 5A is diagram including an isometric view schematically representing a first 3D object including an example portion defining a lattice structure.

[0007] FIG. 5B is a sectional view as taken along lines 5B-5B of the example first assembly in FIG. 5A.

[0008] FIG. 6 is a sectional view like FIG. 5B, except further schematically representing selective removal of an example separable portion of the example lattice structure.

[0009] FIG. 7A is diagram including an sectional view schematically representing an example first 3D object including a recess formed upon selective removal of a separable portion from a lattice structure. [0010] FIG. 7B is diagram like FIG. 7A, and additionally schematically representing the example 3D object with a cover over the recess.

[0011] FIG. 7C is a sectional view schematically representing an example 3D objecting including multiple example lattice portions.

[0012] FIG. 8A is a front elevational view schematically representing an example lattice structure including ring-shaped elements.

[0013] FIG. 8B is a front elevational view schematically representing an example lattice structure including polygonal-shaped elements.

[0014] FIG. 8C is a side sectional view schematically representing an example 3D object including an example lattice structure with a separation path by which releasably connectable rod portions are to be actualized.

[0015] FIG. 8D is a side sectional view of the 3D object in FIG. 8C schematically representing the separable portions spaced apart from each other when the beam is in a disconnected configuration.

[0016] FIG. 9A is block diagram schematically representing an example object formation engine.

[0017] FIG. 9B is block diagram schematically representing an example control portion.

[0018] FIG. 9C is a block diagram schematically representing an example user interface.

[0019] FIG. 10 is flow diagram schematically representing an example method of additively manufacturing a first 3D object including a lattice structure.

Detailed Description

[0020] In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise.

[0021] At least some examples of the present disclosure provide for additively manufacturing a first three-dimensional (3D) object comprising at least a first portion defining a lattice structure of elements, wherein the lattice structure includes a separation path extending at least partially within an interior portion of the lattice structure. In some examples, the separation path may sometimes be referred to as a border.

[0022] The separation path may comprise a first release boundary extending across at least some of the elements of the separation path, wherein the release boundary comprises at least those elements having a reduced-strength segment along the respective elements. In some examples, the reduced-strength segment (of a respective element) may be implemented as at least one of unfused build material, partially fused build material, and an absence of build material. In contrast, some elements of a lattice structure along a separation path which do not have reduced-strength segments may sometimes be referred to elements having a base-strength along a length of the element or be referred to as having base-strength segments across which the separation path extends. In one aspect, the term “base-strength” comprises a strength associated with fully fused build material of the 3D object, and includes those elements of the 3D object which are not reduced-strength elements (i.e. having reduced-strength segments).

[0023] In some examples, the term “base-strength” corresponds to a baseline tensile strength associated with fully fused build material of the 3D object, whereas the term “reduced-strength” corresponds to a reduced tensile strength of a segment at least because the segment is formed of at least one of unfused build material, partially fused build material, and an absence of build material instead of being formed of a fully fused build material.

[0024] In some such examples, the elements comprising a base-strength segment may sometimes be referred to as first elements comprising a first strength while elements comprising a reduced-strength segment may sometimes be referred to as a second element comprising a second strength less than the first strength.

[0025] In some examples, the elements of a lattice structure may comprise elongate elements in which a length of such elements exceeds a width, greatest cross-sectional dimension, and the like of such elements.

[0026] In some examples, the separation path(s) provide a manner by which a portion (or multiple portions) of the lattice structure may be separable from other portions of the lattice structure. In some examples, each separable portion of the lattice structure may sometimes be referred to as a pluckable portion.

[0027] In some examples, by selectively removing (e.g. plucking) one or several separable portions from a lattice structure, a recess may be formed in the lattice structure (and therefore in the 3D object) which has a desired shape which may be simple or which may be complex, such as a recess configured to correspond to (e.g. match) a shape of an article to be placed into the recess.

[0028] In some examples, such lattice structures may define an entire (or substantially) entire additively manufactured 3D object, while in some examples, such lattice structures may comprise just a portion of an additively manufactured 3D object.

[0029] Among other attributes, at least some example lattice structures of the present disclosure enable customizing a geometrical configuration of a 3D object after additive manufacturing. This customization may leverage structural aspects (e.g. separation paths, release boundaries, etc.) of the lattice structure which are formed during additive manufacturing of the 3D object. In some such examples, such customization of a 3D object may be useful in packaging, shipping, or protection of sensitive articles, when the customization may enhance secure reception of an article within the recess formed from removing separable portions of a lattice structure of a 3D object. In some examples, because a separation path includes some solid segments of the respective elements (across which the separation path extends), a lattice structure may bear a shear load and/or compressive loads despite the presence of a release boundary, which comprises some elements including reduced-strength segments (e.g. reduced tensile strength segments), i.e. gapped segments (e.g. split beams), unfused segments, or partially fused of the respective elements (across which the separation path extends). In some examples, the sequence, position, and/or proportion of the reduced-strength segments and base-strength segments (e.g. base tensile strength segments) of the respective elements along a separation path are selected and implemented to resist shear forces and/or to bear compressive loads on the lattice structure.

[0030] In some examples, customization of a geometric shape and/or size of a 3D object after additively manufacturing the 3D object (by leveraging structural aspects of the lattice structure which are formed during additive manufacturing of the 3D object) may comprise forming separation paths (including release boundaries) by which a releasably connectable relationship may be formed between separable portions of the lattice structure.

[0031] These examples, and additional examples, are further described in association with at least FIGS. 1 -10.

[0032] FIG. 1 is a block diagram schematically representing an example method 50 of additively manufacturing an example 3D object. As shown in FIG. 1 , example method 50 comprises additively manufacturing a first three-dimensional object comprising at least a first portion defining a lattice structure of elements. In some such examples, the lattice structure comprises a network of the elements which are interconnected and spaced apart from each other. In some examples, the elements comprise elongate elements, as previously noted.

[0033] In some examples, the lattice structure includes a separation path extending at least partially within an interior portion of the lattice structure, and the separation path may comprise a first release boundary extending across at least some of the elements along the separation path. In some examples, the release boundary comprises at least those elements having a reduced-strength segment along the respective elements, and which may sometimes be referred to as a reduced-strength element. Accordingly, the separation path may comprise a combination of reduced-strength elements and base-strength elements arranged to facilitate selective separability of at least some portions of the lattice structure. [0034] As previously noted, in some examples a reduced-strength segment of a particular element may comprise unfused build material, partially fused build material, and/or an absence of build material. In some examples, at a later point in time after additively manufacturing a lattice structure in which reduced-strength elements were initially formed of unfused build material, the unfused build material may be removed to result in gaps in those respective elements and forming part of the release boundary. In some such examples, such elements may sometimes be referred to as split elements (e.g. split beams), elements comprising split segments, gapped elements, and the like.

[0035] In some examples, a reduced-strength segment and/or a reduced-strength element may have a strength which falls within a range from 0 percent to 80 percent of the strength of a base-strength segment or of a base-strength element. In some such examples, the term “reduced-strength” corresponds to a reduced tensile strength and the term “base-strength” corresponds to a base tensile strength. In some examples, the upper end of the range of reduced-strength for a reduced-strength segment may comprise other percentages (e.g. 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, 5) of the base-strength segment (or base-strength element). Meanwhile, in some examples, the lower end of the range of strength of the reduced-strength may be greater than 0, and may comprise other percentages (e.g. 1 , 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, and so on). [0036] In some examples, a device may comprise instructions, stored in a non- transitory machine-readable storage medium for execution via a processor, to implement at least some of substantially the same features and attributes of the previously described examples of additively manufacturing a 3D object including a lattice structure (50 in FIG. 1 ). In some examples, a device may comprise a print control portion comprising a processor programmed to implement at least some of substantially the same features and attributes of the previously described examples of additively manufacturing a 3D object including a lattice structure (50 in FIG. 1 ). Either of these particular examples may be implemented via at least the examples described later in association with at least FIGS. 9A-9C and/or FIGS. 2-8D and 10. [0037] FIG. 2 is a diagram 100 including a front elevational view schematically representing at least a portion of an example 3D object 102, which comprises an example lattice structure 110. As shown in FIG. 2, the lattice structure 110 comprises a network of interconnected elements 112A, 112B. In the particular example shown in FIG. 2, the elements 112A of lattice structure 110 extend diagonally and generally parallel to each other, while elements 112B also extend diagonally and generally parallel to each other but at an angle relative to the elements 112A. Meanwhile, elements 112C extend across both the elements 112A, 112B and intersect with both elements 112A, 112B at nodes 113 at which elements 112A, 112B intersect with each other. For instance, the lattice structure (e.g. network of interconnected, spaced apart elements) may comprise an end of any one respective elements (e.g. 112A, 112B, 112C) being connected to an end of at least one other respective element (e.g. 112A, 112B, 112C), and a body of the respective elements being spaced apart from each other. It will be understood that the particular example network of interconnected, spaced apart elements 112A, 112B, 112C shown in FIG. 2 provide just one example of many different configurations by which the respective elements, 112A, 112B, 112C can be oriented, interconnected, etc. in a generally spaced relationship relative to each other to provide a lattice structure. Moreover, while the example elements 112A, 112B, 112C shown in FIG. 2 comprise elongate linear elements, it will be understood that elements defining a lattice structure may comprise a wide variety of shapes, sizes, orientations, etc. For examples, just some or all of the elements (e.g. 112A, 112B, 112C) may be curved, just some of all of the elements may comprise a non-uniform thickness, just some or all of the elements may comprise may be rectangular (or circular, hexagonal, etc.) in cross-section, and so on. With this in mind, some of these example shapes, configurations, etc. are illustrated and described later in association with at least FIGS. 8A-8D.

[0038] As further shown in FIG. 2, the lattice structure 1 10 comprises several separation paths (e.g. dashed lines 130A, 130B, 130C, 130D, etc.) extending at least partially within an interior portion 111 of the lattice structure 110. In some examples, some of the separation paths (e.g. 130A, 130B) may extend generally perpendicular (e.g. orthogonal) to some of the other separation paths (e.g. 130C, 130D). As later shown in at least FIG. 8B, in some examples, some separation paths (e.g. 630A) may extend in an orientation which is not perpendicular (i.e. non-orthogonal) to other separation paths (e.g. 630B) and/or not perpendicular to some of the elements forming the lattice structure.

[0039] As further shown in FIG. 2, in some examples the separation paths (e.g. 130A, 130B, 130C, 130D) are defined by at least some of the elements 112A, 112B, 112C comprising a reduced-strength segment 120, which may comprise segment of the particular element which comprises a gap or build material, which is unfused or partially fused. In some such examples, the reduced-strength segments 120 may be formed during additive manufacturing of the lattice structure 110 by providing a reduced-strength segment 120 as a small volume of unfused build material or of partially fused build material, versus the fully-fused build material used to generally form each element 112A, 112B, 112C. In some of examples in which the reduced-strength segments 120 (of respective elements 112A, 112B, 112C) are formed of unfused build material, a post-formation step after additive manufacture of the entire lattice structure 110 may comprise implementing a mechanical, chemical, etc. process by which the unfused build material may be loosened and removed from the lattice structure 110 such that reduced-strength segments 120 become gaps, such as in the example shown in FIG. 2.

[0040] Meanwhile, to help lend stability to the overall lattice structure 110, some of the elements 112A, 112B, 112C along a separation path (e.g., 130A, 130B, 130C, 130D) comprise base-strength segments 121 of respective elements 112A, 112B, 112C which are fully intact (i.e. fully fused without a break).

[0041] In some examples, the reduced-strength segments 120 of elements 112A, 112B, 112C along a respective any one of the separation paths (e.g.130A, 130B, 130C, 130D) define a first release boundary, which facilitates separation of a portion of the lattice structure 110 from the rest of the lattice structure 110. This arrangement will be further described and illustrated in association with at least FIGS. 3, 6. Finally, as previously noted, because the release boundary is made of up the reduced-strength segments 120, the release boundary may sometimes be described as comprising at least one segment comprising unfused build material, segments comprising partially fused build material, and/or gapped segments.

[0042] As further shown by indicator 140 of X, Y, Z reference in FIG. 2, it will be understood that the lattice structure 110 comprises a three-dimensional structure and that separation paths (e.g. 130A, 130B, 130C, 130D) extend three- dimensionally throughout the lattice structure 110. However, in some examples, different regions of the lattice structure 110 may comprise separation paths having different orientations, shapes, etc. than shown in FIG. 2. In some examples, a separation path may comprise shapes which are non-linear, curved, zig-zagged, etc., i.e. having whatever form deemed prudent to accomplish the particular objectives of separability, packaging, etc. for a given 3D object, lattice structure, etc.

[0043] In order to remove a separable portion of the lattice structure 110, a tool (e.g. scissors, knife, etc.) or other mechanical means (e.g. finger pressure) is applied along some of the separation paths (e.g. 130C, 130A) as represented by directional force arrows C in FIG. 2 to cause portion 152 to be separated from a remainder 153 of the lattice structure 110 of the 3D object, as shown in FIG. 3. [0044] As shown in FIG. 3, upon removal of a separable portion 152 of the lattice structure 110, the remainder portion 153 of lattice structure 110 comprises a recess 140 while the separable portion 152 may be discarded or saved for later use in packaging, etc. In some instances, the separable portion 152 may sometimes be referred to as pluckable portion. As shown later in greater details in association with at least FIGS. 6-7B, the recess 140 or void (e.g. empty volume portion) may comprise a recess which is sized, shaped, etc. to receive an object to be packaged or which is to be used to customize the 3D object for other purposes.

[0045] While the example shown in FIG. 3 depicts removal of a single large separable portion 152, it will be understood that in some examples several smaller separable portions may be removed from lattice structure 110 in order to form recess 140. Some such examples may facilitate greater creativity in forming a recess having a particular shape and/or size adapted to receive more complex shaped articles and/or to achieve other objectives. [0046] In some examples, the lattice structure 110 may be formed with just some of the elements (e.g. 112A, 112B, 112C) being rigid or with all the elements of the lattice structure being rigid. In some examples, the lattice structure 110 may be formed with just some elements (e.tg. 112A, 112B, 1 12C) which are resilient or with all the elements of the lattice structure being resilient. In some examples, the lattice structure 110 comprises a combination of rigid elements and resilient elements. In some examples, at least some of the elements of a lattice structure may comprise both a rigid segment and a resilient segment.

[0047] In some examples, such example lattice structures may sometimes be referred to as a non-foam structure, at least to the extent that such lattice structures may be used instead of a foam material for packaging and/or other purposes for which foam may typically be used. However, in at least some examples, the lattice structures do not act like a foam material in terms of responding to a compressive load. For example, at least some example non foam lattice structures of the present disclosure provide a relatively flat stress- strength curve such that increases in an amount of compressive forces applied to the lattice structure (and any article held within a recess of the lattice structure) do not result in increasing amounts of force being applied to the article. In sharp contrast, typical foam materials exhibit a linear stress-strength curve by which increases in the amount of compressive forces applied to the foam material result in corresponding increases in force being applied to an article purportedly being cushioned or protected by a foam material.

[0048] FIG. 4 is a diagram 201 schematically representing an example device 200 to additively manufacture a single 3D assembly including a first 3D object including a lattice structure, such as provided via the examples previously described in association with at least FIGS. 1 -3 and/or later described in association with at least FIGS. 5A-10. Accordingly, the device 200 in FIG. 4 may comprise one example implementation of the arrangement 50 in FIG. 1 and/or comprise at least some of substantially the same features and attributes for additively manufacturing a 3D object as previously described in association with FIGS. 1 -3. [0049] As shown in FIG. 4, in some examples, the device 200 comprises a material distributor 250 and a fluid dispenser 258. The material distributor 250 is arranged to dispense a build material layer-by-layer onto a build pad 242 to additively form the 3D object 280. Once formed, the 3D object 280 may be separated from the build pad 242. It will be understood that a 3D object of any shape and any size can be manufactured, and the object 280 depicted in FIG. 4 provides just one example shape and size of a 3D object. In some instances device 200 may sometimes be referred to as a 3D printer. Accordingly, the build pad 242 may sometimes be referred to as a print bed or a receiving surface. [0050] It will be understood that the material distributor 250 may be implemented via a variety of electromechanical or mechanical mechanisms, such as doctor blades, slot dies, extruders, and/or other structures suitable to spread, deposit, and/or otherwise form a coating of the build material in a generally uniform layer relative to the build pad 242 or relative to a previously deposited layer of build material.

[0051] In some examples, the material distributor 250 has a length (L1) at least generally matching an entire length (L1) of the build pad 242, such that the material distributor 250 is capable of coating the entire build pad 242 with a layer 282A of build material in a single pass as the material distributor 250 travels the width (W1) of the build pad 242. In some examples, the material distributor 250 can selectively deposit layers of material in lengths and patterns less than a full length of the material distributor 250. In some examples, the material distributor 250 may coat the build pad 242 with a layer 282A of build material(s) using multiple passes instead of a single pass.

[0052] It will be further understood that a 3D object additively formed via device 200 may have a width and/or a length less than a width (W1) and/or length (L1) of the build pad 242.

[0053] In some examples, the material distributor 250 moves in a first orientation (represented by directional arrow F) while the fluid dispenser 258 moves in a second orientation (represented by directional arrow S) generally perpendicular to the first orientation. In some examples, the material distributor 250 can deposit material in each pass of a back-and-forth travel path along the first orientation while the fluid dispenser 258 can deposit fluid agents in each pass of a back-and- forth travel path along the second orientation. In at least some examples, one pass is completed by the material distributor 250, followed by a pass of the fluid dispenser 258 before a second pass of the material distributor 250 is initiated, and so on.

[0054] In some examples, the material distributor 250 and the fluid dispenser 258 can be arranged to move in the same orientation, either the first orientation (F) or the second orientation (S). In some such examples, the material distributor 250 and the fluid dispenser 258 may be supported and moved via a single carriage while in some such examples, the material distributor 250 and dispenser 258 may be supported and moved via separate, independent carriages.

[0055] In some examples, the build material used to generally form the 3D object comprises a polymer material. In some examples, the polymer material comprises a polyamide material. However, a broad range of polymer materials (or their combinations) may be employed as the build material. In some examples, the build material may comprise a ceramic material. In some examples, the build material may take the form of a powder while in some examples, the build material may take a non-powder form, such as liquid or filament. Regardless of the particular form, at least some examples of the build material is suitable for spreading, depositing, extruding, flowing, etc. in a form to produce layers (via material distributor 250) additively relative to build pad 242 and/or relative to previously formed first layers of the build material.

[0056] In some examples, the fluid dispenser 258 shown in FIG. 4 comprises a printing mechanism, such as an array of printheads, each including a plurality of individually addressable nozzles for selectively ejecting fluid agents onto a layer of build material. Accordingly, in some examples, the fluid dispenser 258 may sometimes be referred to as an addressable fluid ejection array. In some examples, the fluid dispenser 258 may eject individual droplets having a volume on the order of ones of picoliters or on the order of ones of nanoliters.

[0057] In some examples, fluid dispenser 258 comprises a thermal inkjet (TIJ) array. In some examples, fluid dispenser 258 may comprise a piezoelectric inkjet (PIJ) array or other technologies such as aerosol jetting, anyone of which can precisely, selectively deposit a small volume of fluid. In some examples, fluid dispenser 258 may comprise continuous inkjet technology.

[0058] In some examples, the fluid dispenser 258 selective dispenses droplets on a voxel-by-voxel basis. In one sense a voxel may be understood as a unit of volume in a three-dimensional space. In some examples, a resolution of 1200 voxels per inch in the x-y plane is implemented via fluid dispenser 258. In some examples, a voxel may have a height H2 (or thickness) of about 100 microns, although a height of the voxel may fall between about 80 microns and about 100 microns. However, in some examples, a height of a voxel may fall outside the range of about 80 to about 100 microns. FIG. 4 also illustrates the fully formed 3D object 280 having a height H1 .

[0059] In some examples, the height (H2) of the voxel may correspond to a thickness of one layer (e.g. 282A) of the build material.

[0060] In some examples, the fluid dispenser 258 has a width (W1 ) at least generally matching an entire width (W1 ) of the build pad 242, and therefore may sometimes be referred to as providing page-wide manufacturing (e.g. page wide printing). In such examples, via this arrangement the fluid dispenser 258 can deposit fluid agents onto the entire receiving surface in a single pass as the fluid dispenser 258 travels the length (L1 ) of the build pad 242. In some examples, the fluid dispenser 258 may deposit fluid agents onto a given layer of material using multiple passes instead of a single pass.

[0061] In some examples, fluid dispenser 258 may comprise, or be in fluid communication with, an array of reservoirs to contain various fluid agents 262. In some examples, the array of reservoirs may comprise a fluid supply 215. In some examples, the fluid supply 215 comprises reservoirs to hold various fluids, such as a carrier (e.g. ink flux) by which various agents may be applied in a fluidic form. [0062] In some examples, at least some of the fluid agents 262 may comprise a fusing agent, a color agent, detailing agent, etc. to enhance formation of each layer 282A of build material. In particular, upon application onto the build material at selectable positions via the fluid dispenser 258, the respective fusing agent and/or detailing agent may diffuse, saturate, and/or blend into the respective layer of the build material at the selectable positions. As noted elsewhere, a volume and/or location of application of the fusing agent and/or detailing agent on particular portions of the build material may be used to selectively control a degree of fusion (e.g. solidification) of the build material to which the particular agent(s) are applied.

[0063] As further shown in FIG. 4, in some examples, the at least partially formed 3D object 280 on build pad 242 comprises a first portion 271 A and a second portion 271 B with dashed line 273 representing a boundary between the first portion 271 A and the second portion 271 B. The 3D object 280 may have an exterior side surface 288.

[0064] During formation of a desired number of layers 282A of the build material, in some examples the fluid dispenser 258 may selectively dispense droplets of fluid agent(s) 262 at some first selectable voxel locations 274 of at least some respective layers 282A to at least partially define the first portion 271 A of the 3D object. It will be understood that a group 272 of first selectable voxel locations 274, or multiple different groups 272 of first selectable voxel locations 274 may be selected in any position, any size, any shape, and/or combination of shapes. [0065] In some examples, the at least some first selectable voxel locations 274 may correspond to an entire layer 282A of a 3D object or just a portion of a layer 282A. Meanwhile, in some examples, the 3D object may comprise a part of a larger object. In some examples, each first selectable voxel location 274 corresponds to a single voxel.

[0066] As further shown in FIG. 4, in some examples device 200 comprises an energy source 210 for applying energy (e.g. irradiating) to the deposited build materials, fluid agents (e.g. fusing agent, detailing agent, etc.) to cause heating of the material, which in turn results in the fusing of particles of the material relative to each other, with such fusing occurring via melting, sintering, etc. In portions of the 3D object in which full solidification is desired, such as for structural purposes, then a full volume of the respective fusing agents and/or detailing agents are applied to those portions of the 3D object. Flowever, as noted elsewhere previously, in portions of a lattice structure (e.g. 110 in FIG. 2) of a 3D object for which it is desired to form a separation path (e.g. 130A, 130B, 130C, 130D in FIG. 2), then a lower volume of the respective fusing agent(s) is to be applied to create partial fusion (instead of full fusion) or unfused build material to form reduced-strength segments 120 (FIG. 2). Moreover, adjustments may be made to a volume of applied detailing agent(s). In this way, applying selectivity in the volume of respective fusing agent(s) and/or detailing agent(s) may help form a release boundary defined by at least reduced-strength segments 120 along a separation path (e.g. 130A, 130B, 130C, 130D).

[0067] After application of the radiation from energy source 210, a layer 282A of build material is formed and additional layers 282A of build material may be formed in a similar manner as represented in FIG. 4. In view of the foregoing examples, it will be understood that any given formed layer 282A of build material may include at least some portions which are unfused, partially fused, and/or fully fused in order to achieve the objectives regarding formation of a lattice structure 110, selectively removable separable portions of the lattice structure 110, separation paths, release boundaries, and related aspects described throughout the various examples of the present disclosure.

[0068] In some examples, the energy source 210 may comprise a gas discharge illuminant, such as but not limited to a Flalogen lamp. In some examples, the energy source 210 may comprise multiple energy sources. As previously noted, energy source 210 may be stationary or mobile and may operate in a single flash or multiple flash mode.

[0069] As shown in FIG. 4, in some examples device 200 may comprise a control portion 217 to direct operations of device 200. In some examples, control portion 217 may be implemented via at least some of substantially the same features and attributes as control portion 800, as later described in association with at least FIG. 9B.

[0070] In some examples the device 200 in FIG. 4 can be used to additively form a 3D object via a powder bed-based process, such as MultiJet Fusion (MJF) process (available from HP, Inc.). It will be understood that in some examples other additive manufacturing techniques (e.g. Fused Deposition Modeling (FDM), LaserProFusion, Selective Laser Sintering (SLS), Selective Laser Melting (SLM), 3D binder jetting, Electron Beam Melting (EBM), ProJet Fusion, etc.) may be used for form a 3D object. Accordingly, in such arrangements, the examples of the present disclosure may be implemented according to the particular build materials, application techniques, curing techniques, etc. associated with each particular modality of manufacturing.

[0071] FIG. 5A provides an isometric view schematically representing one example 3D object 301 A including an example lattice structure 302A, which may comprise (or be formed according to) at least some of substantially the same features and attributes as previously described in association with at least FIGS. 1 -4. Meanwhile, FIG. 5B is a sectional view as taken along lines 5B-5B of FIG. 5A.

[0072] As shown in FIG. 5A, the first 3D object 105 comprises a pair opposite end portions 102A, 102B, a top portion 106A and opposite bottom portion 106B, and a front portion 104A and opposite back portion 104B. While the first 3D object 105 is represented in FIG. 5A as a rectangular cuboid for illustrative simplicity, it will be understood that first 3D object 105 may comprise a wide variety of shapes and sizes, and may comprise a functional article and/or an aesthetic (i.e. non functional) article. The 3D object 105 may function as a stand-alone article in some examples, or may function as part of a larger machine, assembly, etc. in some examples.

[0073] As further shown in FIGS. 5A-5B, the first 3D object 301 A may comprise a first portion 305 within which is formed a lattice portion 302A. In some examples, the first portion 305 comprises solid material, such as fully-fused build material. Meanwhile, the lattice portion 302A may comprise a lattice structure like lattice structure 110 in FIGS. 2-3 or any one of the different varieties of lattice structures as previously described or later described in various examples of the present disclosure.

[0074] Moreover, while the lattice structure 302A is shown in FIG. 5A as comprising a rectangular cuboid, it will be further understood that the lattice structure 302A may comprise a wide variety of shapes, sizes, orientations, etc. within the 3D object 301 A.

[0075] As further shown in the sectional view of FIG. 5B, a separable portion 352 may be cut or otherwise selectively removed from the rest of lattice structure 302A as represented by directional force arrows C, and in a manner similar to that previously described in association with FIGS. 2-3. In some instances, the separable portion 352 may sometimes be referred to as pluckable portion. Upon removal of selectively separable portion 352, the modified lattice structure 302B defines a void or recess 337 as shown in the diagram 360 of FIG. 6 with separable portion 352 being discarded, used for other purposes, etc. As represented by indicator 140, the newly formed recess 337 in the modified lattice structure 302B will extend three-dimensionally within, and through, the modified lattice structure 302B as further schematically represented in the sectional view of FIG. 7A. As previously noted, the recess 130 may comprise a wide variety of shapes and sizes other than the rectangular cuboid shape shown in FIGS. 6-7A, which may or may not depend on a size and/or shape of the lattice structure 302A and/or 3D object 305A.

[0076] In particular, FIG. 7A is a sectional view of the example modified 3D object 301 B (including modified lattice structure 302B), except showing the modified 3D object in an upside down orientation (relative to the view shown in FIGS. 5A-6). FIG. 7A reveals the convenience of recess 337 in modified lattice structure 302B to receive an article for packaging or other purposes. In this arrangement, the modified lattice structure 302B may help cushion or otherwise protect the article received therein.

[0077] As further shown in FIG. 7B, in some examples a lattice portion 381 may be provided to act as a cover at the top portion of recess 337 in order to further protect any article held within recess 337. In some examples, the lattice portion 381 may comprise a portion of the separable portion 352, which was removed from the lattice structure 302A (FIG. 6). In some examples, materials and/or structures other than lattice portion 381 may be used as a cover to recess 337. [0078] As shown in FIG. 7C, in some examples a 3D object 391 A (like 3D object 305A) may comprise multiple separate regions comprising lattice structures 392A, 392B, etc. The different lattice structures 392A, 392B may have the same shape, volume, etc. as each other, or they may have different shapes, volumes, from each other. Moreover, both of the different lattice structures 392A, 392B may be located with a portion 393 of the respective lattice structures 392A, 392B exposed at a surface (e.g. 106B) of the 3D object 392A. [0079] While FIG. 7C depicts 3D object 391 A as having a relatively simple geometric shape of a rectangular cuboid, it will be understood that a 3D object may comprise more complex shapes (e.g. star, L-shaped, T-shaped, etc.) and that each diverging portion of such complex shapes may comprise its own separate lattice structure, if desired.

[0080] Moreover, in some examples in which a 3D object 391 A comprises more complex shapes, the entire (or substantially the entire) 3D object 391 A may comprise a lattice structure with multiple selectively separable portions.

[0081] FIGS. 8A and 8B are front plan views of example lattice structures 510, 610, either of which may be form part, or all of, an additively manufactured 3D object 500, 600, respectively. In some examples, each lattice structure 510, 610 may be implemented via at least some of substantially the same features and attributes as in the examples described in association with at least FIGS. 1 -7C and/or FIGS. 9A-10.

[0082] As shown in FIG. 8A, in some examples lattice structure 510 comprises a network of interconnected ring-shaped elements 512A, 512B with some elements 512B overlapping (e.g. juxtaposed onto) some other elements 512A or 512B. It will be understood that the various ring-shaped elements 512A, 512B may overlap or be interconnected in a manner other than that shown in FIG. 8A. [0083] In some examples, at least some separation paths 530A, 530B, 530C, 530D may extend across at least a portion of the lattice structure 510, with the separation path including a release boundary defined by some combination or reduced-strength segments 120 and base-strength segments 121 (e.g. fully fused segments) of the ring-shaped elements 512A, 512B. As previously described with respect to prior examples, the reduced-strength segments 120 may comprise gaps, unfused build material, and/or partially fused build material.

[0084] Meanwhile, FIG. 8B illustrates a lattice structure 610 comprising a network of interconnected polygon-shaped elements 612. While the polygonal elements 612 are shown as being hexagons, they may comprise any type of polygonal shape, such as pentagons, octagons, or other polygonal variations. Some of the elements 612 may be sized differently from each other, while some of the elements 612 may overlap with each other, and/or be interconnected in various ways, etc. Like other example lattice structures of the present disclosure, separation paths 630A, 630B may extend across the lattice structure 610, with each separation path including a release boundary defined by some combination of reduced-strength portions 120 and base-strength segments 121 of the elements 612. As further shown in FIG. 8B, in some examples the separation paths 630A, 630B may have varied orientations as compared to orientation of separation paths in the examples of FIGS. 2-3.

[0085] While the examples of FIGS. 8A and 8B provide further examples different potential shapes for elements of a lattice structure, it will be further understood that in some examples, at least some elements of a lattice structure may comprise irregular shapes, irregular patterns, etc., as further described later in association with at least network engine 740 of object formation engine 700 in FIG. 9A. [0086] FIG. 8C is a side sectional view schematically representing an example 3D object 650 including a lattice structure 657 with separable portions 658A, 659A to form a releasably securable rod connection at seam 653. In some examples, the seam 653 also may correspond to a separation path by which portion 658A becomes separated from portion 659A (as represented via directional force arrows S) via cutting or other mechanical means, such that two different rod portions 654, 656 are created from the single 3D object as shown in FIG. 8D. [0087] As further shown in FIG. 8C, in some examples the 3D object 650 may comprise lattice structure 657 (represented via cross-hatching), which includes portions 658A, 659A while portions 658B, 659B of 3D object 650 comprise a non lattice structure, i.e. fused build material which is solid. Flowever, in some examples, the entire 3D object 650 may comprise a lattice structure such that portions 658B, 659B also comprise part of the lattice structure 657.

[0088] As further shown in FIG. 8D, upon separation of rod portions 654, 656 it can be seen that an end 683 of the first rod portion 654 comprises a recessed portion 680 while an end 684 of second rod portion 656 comprises a conical portion 682 which has a shape and size corresponding to the size and/or shape of the recessed portion 680. Accordingly, upon urging the respective rod portions 654, 656 toward each other (as represented by directional arrow T) and back into releasably connection with each other, the conical portion 682 of rod portion 656 would fit snugly into the recessed portion 680 of rod portion 654.

[0089] Accordingly, via this arrangement, a 3D object 650 may be additively manufactured as a single structure as shown in FIG. 8C, which includes a lattice structure 657 with a separation path 653. At an appropriate time and upon application of an appropriate mechanical force (e.g. cutting, bending, etc.) at or near the separation path 653, the single structure becomes separated into the different rod portions 654, 656 such that a releasably connectable rod arrangement is available for use as represented in FIGS. 8C-8D. In some instances, when still arranged as a single structure as shown in FIG. 8C, the rod portions may sometimes be referred to as potentially separate rod portions 654, 656 while after separation, as shown in FIG. 8D, the releasably connectable rod portions 654, 656 may sometimes be referred to as actualized separate rod portions 654, 656.

[0090] In some examples, the principle of separability (after additive manufacture of a 3D object including a lattice structure) can be implemented via other types, shapes, etc. of portions of a lattice structure by which separation of those portions creates a releasably connectable (or mating) relationship between the separable portions.

[0091] FIG. 9A is a block diagram schematically representing an example object formation engine 700. In some examples, the object formation engine 700 may form part of a control portion 800, as later described in association with at least FIG. 9B, such as but not limited to comprising at least part of the instructions 811 . In some examples, the object formation engine 700 may be used to implement at least some of the various example devices and/or example methods of the present disclosure as previously described in association with FIGS. 1 -8D and/or as later described in association with FIGS. 9B-10. In some examples, the object formation engine 700 (FIG. 9A) and/or control portion 800 (FIG. 9B) may form part of, and/or be in communication with, an object formation device, such as the additive manufacturing device 200 in FIG. 4. Accordingly, in some examples, at least some aspects of control portion 800 may comprise one example implementation of the control portion 217 of device 200 in FIG. 4. [0092] As shown in FIG. 9A, in some examples the object formation engine 700 may comprise a material distributor engine 702, fluid dispenser engine 704, and energy source engine 706.

[0093] As shown in FIG. 9A, in some examples the material distributor engine 702 controls distribution of layers of build material relative to build pad (e.g. 242 in FIG. 4) and/or relative to previously deposited layers of build material. In some examples, the material distributor engine 702 comprises a material parameter to specify which build material(s) and the quantity of such build material which can be used to additively form a body of the 3D object. In some examples, these materials are deposited via build material distributor 250 of device 200 (FIG. 4). [0094] In some examples, the material controlled via the material distributor engine 702 may comprise polymers, ceramics, etc. having sufficient strength, formability, toughness, resiliency, etc. for the intended use of the 3D object with at least some example materials being previously described in association with at least FIG. 4.

[0095] As shown in FIG. 9A, in some examples the fluid dispenser engine 704 may specify which fluid agents are to be selectively deposited onto a layer (or portions of a layer) of build material on a voxel-by-voxel basis, as previously described in association with at least FIG. 4. In some examples, such agents are deposited via fluid dispenser 258 (FIG. 4). In some examples, the fluid dispenser engine 704 may comprise a carrier function and an agent function to apply fluid agents, such as the carrier, fusing, detailing, etc. as previously described in association with at least FIG. 4.

[0096] In particular, via the fluid dispenser engine 704, application of a selectable volume (and location) of a fusing agent and/or detailing agent may be used to selectably control a degree of fusion at selectable voxel locations (274 in FIG. 4). In some such examples, such control may be used to form lattice structures, separable portions, separation paths, release boundaries, etc. as described throughout various examples of the present disclosure. In some examples, fluid dispenser engine 704 may specify a number of fluid application channels, volume of fluid to be applied, during which pass the particular fluid channel is active, etc. [0097] In some examples, the energy source engine 706 of object formation engine 700 is to control operations of at least one energy source (e.g. 210 in FIG. 4). In some examples, the energy source engine 706 may control an amount of time that energy (e.g. radiation) from the energy source 210 (FIG. 4) is emitted toward the material, agents, etc. on a layer of build material, with a resulting degree of fusion depending on a volume (and location) of fusing agent(s) and/or detailing agent(s) applied at particular voxel locations (274 in FIG. 4). In some examples, the energy source 706 may irradiate the targeted layer (of the 3D object under formation) in a single flash or in multiple flashes. In some examples, the energy source may remain stationary (i.e. static) or may be mobile. In either case, during such irradiation, the energy source engine 706 controls the intensity, volume, and/or rate of irradiation.

[0098] As further shown in FIG. 9A, in some examples, the object formation engine 700 comprise a lattice formation engine 730, which is to control additive formation of a first 3D object which comprises at least a first portion comprising a lattice structure (and related variations), as previously described in various examples throughout the present disclosure. In some examples, in cooperation with at least the fluid dispenser engine 704, the lattice formation engine 730 may provide at least partial control over a volume and location at which a fusing agent(s) and/or detailing agent(s) are deposited onto a layer of build material, which in turn provides control over formation of a lattice structure, separation path(s), release boundary, etc. as further described below. In one aspect, the relative volume of the fusing agent(s) and/or detailing agent(s) deposited to a particular voxel location (e.g. 274 in FIG. 4) determines a degree of fusion of the particular voxel location, as previously described in association with at least FIG. 4. In particular, in the absence of a fusing agent applied to a particular voxel location and upon application of radiation per energy source (e.g. 210 in FIG. 4), no fusion will take place for the particular voxel location(s) 274 (FIG. 4). This arrangement will result in unfused build material (i.e. free powder build material) at the particular voxel location(s) 274. On the other hand, upon depositing a selectable volume of at least fusing agent(s) and/or detailing agent(s) to a particular voxel location(s) 274, one can control a degree of fusion of the build material at the particular voxel location(s) 274. Via this arrangement, the particular voxel location(s) 274 may become at least partially fused and in some instances, fully fused.

[0099] As shown in FIG. 9A, in some examples, the lattice formation engine 730 comprises a location parameter 732, a volume parameter 734, a shape parameter 736, a network engine 740, a separability engine 750, and/or a quantity parameter 758.

[00100] In some examples, in order to additively manufacture a 3D object including at least a first portion comprising a lattice structure with separable portions (e.g. FIGS. 1 -8D), such additive manufacturing may be implemented to form a lattice structure (e.g. 110 in FIGS. 2-3, etc.) comprising a selectable location (parameter 732), volume (parameter 734), and/or shape (parameter 736) within the 3D object. For instance, in some examples, the selectable location (732) may comprise specifying a location within the particular 3D object at which a lattice structure will be formed, and may be expressed via three-dimensional (x, y, z) coordinates of the boundaries of the lattice structure.

[00101] In some such examples, the volume can be specified as an absolute volume or as a relative volume of the first 3D object. Similarly, as later described in association with the network engine 740 and/or the separability engine 750, these same parameters (732, 734, 736) may be used to determine a respective location, volume, shape, etc. of elements of a network (of interconnected elements) and/or of separation paths within a lattice structure.

[00102] In some examples the network engine 740 (of the lattice formation engine 730 of the object formation engine 700) is to track and/or control features and attributes regarding elements (parameter 742) forming a lattice structure. For example, as further represented in FIG. 9A, via parameter 742 the network engine 740 may control a type (parameter 744), spacing (parameter 746), and/or orientation (parameter 748) of elements defining a lattice structure. For example, the type parameter 744 may specify that an element comprise an elongate shaped element, a ring-shaped element, a triangular-shaped element, a polygonal-shaped element, and so on. In some instances, the elongate elements may sometimes be referred to as beams. In some examples, at least some of the elements of a particular lattice structure may define a free-form curved portion within, or throughout, at least a portion of the lattice structure.

[00103] In some examples, the type parameter 744 may specify a general shape or type of an element and/or may specify a shape or type of a cross-section of the elements. It will be further understood that in specifying the type of elements, the type parameter 744 also may be used to specify a thickness, length, etc. of elements, as well as specifying that at least some elements comprise non- uniform thicknesses, lengths, etc. In some examples, all of the elements of a particular lattice structure (e.g. 110 in FIG. 2) may comprise the same type of elements, while in some examples, a particular lattice structure may comprise a plurality of different type of elements arranged in an interconnected network with spacing between the respective elements. The different types of elements arranged within a single lattice structure may facilitate achieving different structural support objectives, separability objectives, etc. To the extent that a given 3D object may comprise several different lattice structures in some examples, each lattice structure may have the same types of elements as other lattice structures or the different lattice structures may comprise a different type of element than other lattice structures.

[00104] With further reference to FIG. 9A, in some examples, the separability engine 750 of the object formation engine 700 is to control formation and placement of separation paths within a lattice structure (e.g. 110 in FIG. 2) to facilitate later selective removal of separable portions (e.g. 152 in FIG. 2) of a lattice structure, as previously described throughout various examples of the present disclosure.

[00105] In some examples, the separability engine 750 is to track and/or control an orientation (parameter 752), location (732), volume (734), and/or shape (736) of the separation paths (e.g. 130A, 130B, 130C, 130D) extending within, and throughout, a lattice structure. It will be apparent that any desired number of separation paths may be formed in a given lattice structure depending on the particular objectives for separability of portions of the lattice structure.

[00106] In some examples, per parameter 754, the separability engine 750 may specify a proportion of elements (along a separation path) which comprise a weakened segment and elements which comprise fully intact segments, so as to determine a relative ease of separability for a particular separation path. As previously noted, a weakened segment (e.g. 120 in FIG. 2) may comprise partially fused build material or unfused build material, while the fully intact segments (e.g. 121 in FIG. 2) defining a portion of a separation path may comprise fully fused build material.

[00107] Similarly, in some examples, per parameter 756, the separability engine 750 may specify a sequence of the respective reduced-strength segments 120 (along a separation path) and respective base-strength segments 121 so as to determine a relative ease of separability, directionality, etc. for a particular separation path. With this in mind, via the sequence parameter 756, the separability engine 750 also may specify the number of consecutive reduced- strength segments 120 and number of base-strength segments 120 along a particular separation path, as well as an order of the respective reduced-strength segments 120 and base-strength segments 121 along a particular separation path within a lattice structure. In some instances, a sequence or pattern of reduced-strength segments 120 may sometimes be referred to as a release boundary, which as previously described, facilitates separability of selectable portions of a lattice structure along a respective separation path.

[00108] In some examples, via quantity parameter 758, the lattice formation engine 730 can control, specify, etc. a quantity of lattice structures for a particular 3D object, a quantity of elements for a particular lattice structure, a quantity of separation paths, etc.

[00109] It will be understood that various functions and parameters of object formation engine 700 may be operated interdependently and/or in coordination with each other, in at least some examples.

[00110] FIG. 9B is a block diagram schematically representing an example control portion 800. In some examples, control portion 800 provides one example implementation of a control portion (e.g. 217 in FIG. 4) forming a part of, implementing, and/or generally managing the example additive manufacturing devices, as well as the particular portions, components, material distributors, fluid supply, fluid dispensers, energy sources, control portion, instructions, engines, functions, parameters, and/or methods, as described throughout examples of the present disclosure in association with FIGS. 1 -8D and 9B-10. In some examples, control portion 800 includes a controller 802 and a memory 810. In general terms, controller 802 of control portion 800 comprises at least one processor 804 and associated memories. The controller 802 is electrically couplable to, and in communication with, memory 810 to generate control signals to direct operation of at least some the object formation devices, various portions and elements of the example additive manufacturing devices, as well as the particular portions, components, material distributors, fluid supply, fluid dispensers, energy sources, control portion, instructions, engines, functions, parameters, and/or methods, as described throughout examples of the present disclosure. In some examples, these generated control signals include, but are not limited to, employing instructions 811 stored in memory 810 to at least direct and manage additive manufacturing of 3D objects in the manner described in at least some examples of the present disclosure. In some instances, the controller 802 or control portion 800 may sometimes be referred to as being programmed to perform the above- identified actions, functions, etc. In some examples, at least some of the stored instructions 811 are implemented as a, or may be referred to as, a 3D print engine, an object formation engine, and the like, such as but not limited to the object formation engine 700 in FIG. 9A.

[00111] In response to or based upon commands received via a user interface (e.g. user interface 820 in FIG. 9C) and/or via machine readable instructions, controller 802 generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller 802 is embodied in a general purpose computing device while in some examples, controller 802 is incorporated into or associated with at least some of the additive manufacturing devices, as well as the particular portions, components, material distributors, fluid supply, fluid dispensers, energy sources, control portion, instructions, engines, functions, parameters, and/or methods, etc. as described throughout examples of the present disclosure. [00112] For purposes of this application, in reference to the controller 802, the term “processor” shall mean a presently developed or future developed processor (or processing resources) that executes machine readable instructions contained in a memory or that includes circuitry to perform computations. In some examples, execution of the machine readable instructions, such as those provided via memory 810 of control portion 800 cause the processor to perform the above-identified actions, such as operating controller 802 to implement the formation of 3D objects to include at least a portion comprising a lattice structure by which portions of the 3D object are selectively removable and related examples, as generally described in (or consistent with) at least some examples of the present disclosure. The machine readable instructions may be loaded in a random access memory (RAM) for execution by the processor from their stored location in a read only memory (ROM), a mass storage device, or some other persistent storage (e.g., non-transitory tangible medium or non-volatile tangible medium), as represented by memory 810. The machine readable instructions may include a sequence of instructions, a processor-executable machine learning model, or the like. In some examples, memory 810 comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller 802. In some examples, the computer readable tangible medium may sometimes be referred to as, and/or comprise at least a portion of, a computer program product. In other examples, hard wired circuitry may be used in place of or in combination with machine readable instructions to implement the functions described. For example, controller 802 may be embodied as part of at least one application-specific integrated circuit (ASIC), at least one field-programmable gate array (FPGA), and/or the like. In at least some examples, the controller 802 is not limited to any specific combination of hardware circuitry and machine readable instructions, nor limited to any particular source for the machine readable instructions executed by the controller 802.

[00113] In some examples, control portion 800 may be entirely implemented within or by a stand-alone device.

[00114] In some examples, the control portion 800 may be partially implemented in one of the object formation devices and partially implemented in a computing resource separate from, and independent of, the object formation devices but in communication with the object formation devices. For instance, in some examples control portion 800 may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion 800 may be distributed or apportioned among multiple devices or resources such as among a server, an object formation device, and/or a user interface.

[00115] In some examples, control portion 800 includes, and/or is in communication with, a user interface 820 as shown in FIG. 9C. In some examples, user interface 820 comprises a user interface or other display that provides for the simultaneous display, activation, and/or operation of at least some of the additive manufacturing devices, as well as the particular portions, components, material distributors, fluid supply, fluid dispensers, energy sources, control portion, instructions, engines, functions, parameters, and/or methods, etc., as described in association with FIGS. 1 -9B and 10A-10. In some examples, at least some portions or aspects of the user interface 820 are provided via a graphical user interface (GUI), and may comprise a display 824 and input 822. [00116] FIG. 10 is a flow diagram of an example method 900. In some examples, method 900 may be performed via at least some of the devices, components, material distributors, fluid supply, fluid dispensers, energy sources, instructions, control portions, engines, functions, parameters, and/or methods, etc. as previously described in association with at least FIGS. 1 -9C. In some examples, method 900 may be performed via at least some of the devices, components, material distributors, fluid supply, fluid dispensers, energy sources, instructions, control portions, engines, functions, parameters, and/or methods, etc. other than those previously described in association with at least FIGS. 1 -9C. [00117] As shown at 902 in FIG. 10, method 900 comprises additively manufacturing a first 3D object including at least a first portion arranged in a lattice structure, the lattice structure including a first portion separable from a second portion along a border. In some examples, the border is defined by at least some first elements of the lattice structure having a first strength and at least some second elements of the lattice structure having a second strength less than the first strength. In some examples, the second elements include at least a portion defined by at least one of unfused build material and partially fused build material. In some examples, at least some of the respective first and second elements comprise elongate elements.

[00118] In some examples, method 900 comprises implementing the border according to at least one of: a selectable proportion of the first elements and second elements; and a selectable sequence of the respective first elements and second elements.

[00119] Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein.

Claims

1. A non-transitory machine-readable storage medium, encoded with instructions executable by a processor, comprising: instructions to generate data representing a three-dimensional object model for use in additively manufacturing a first three-dimensional object comprising at least a first portion defining a lattice structure of elements, the lattice structure including a separation path extending at least partially within an interior portion of the lattice structure, wherein the separation path includes a release boundary extending through at least some of the elements along the separation path, with the at least some elements comprising a reduced-strength segment.

2. The non-transitory machine readable medium of claim 1 , wherein the reduced-strength segment comprises at least one of: unfused build material; partially fused build material; and an absence of build material.

3. The non-transitory machine readable medium of claim 1 , wherein the separation path includes a first portion extending in a first orientation through the interior portion of the lattice and a second portion extending in a second orientation extending through the interior portion to be perpendicular to the first portion.

4. The non-transitory machine readable medium of claim 1 , wherein the separation path defines a three-dimensional pattern to permit selective removal of a first portion of the three-dimensional object, along the separation path, from a second portion of the three-dimensional object.

5. The non-transitory machine readable medium of claim 1 , wherein the instructions are to define the lattice structure as a pattern of elements, wherein the pattern is configurable according to at least one of: an element type parameter; an element spacing parameter; and an element orientation parameter.

6. The non-transitory machine readable medium of claim 1 , wherein the lattice structure of elements, including the separation path extending at least partially within the interior portion, is configured to bear a compression load from an external force.

7. The non-transitory machine readable medium of claim 1 , wherein the separation path is defined by a combination of first elements including base- strength segments and second element including reduced-strength segments, wherein the respective first and second elements are arranged in a proportion to resist shear forces on the lattice structure.

8. The non-transitory machine readable medium of claim 1 , wherein the instructions are to implement the separation path according to at least one of: a selectable proportion of base-strength elements and reduced-strength elements; and a selectable sequence of the respective base-strength elements and reduced-strength elements.

9. A print control portion, comprising: a processor programmed to additively manufacture a 3D object including at least a portion comprising a network of interconnected, spaced apart beams, the network including a separation path extending at least partially within an interior portion of the network along a plurality of the respective beams and at least partially defined by a release boundary extending through at least some of the respective beams along the separation path, wherein the at least some beams along the release boundary comprise a reduced-strength segment.

10. The print control portion of claim 9, wherein the print control portion is at least one of: in communication with a 3D printer; and incorporated as part of the 3D printer, wherein the 3D printer comprises: a build unit including a build platform; a build material distributor to distribute a build material on the build platform; a fluid dispenser to selectively apply at least one agent to the build material, the at least one agent comprising a detailing agent and a fusing agent; an energy source to apply energy to cause fusing, via the at least one agent, of the build material to form the 3D object of the build material, wherein the print control portion is to control at least the material distributor, the fluid dispenser, and the energy source to additively form the 3D object including the network of interconnected beams.

11 . The 3D printing system of claim 9, wherein the print control unit is to implement the network via an end of any one respective beam being connected to an end of at least one other respective beam, and a body of the respective beams being spaced apart from each other.

12. The 3D printing system of claim 9, wherein the separation path defines a three-dimensional pattern to permit selective removal of a first portion of the three- dimensional object, along the separation path, from a second portion of the three- dimensional object.

13. A method comprising: additively manufacturing a 3D object including at least a first portion arranged in a lattice structure, the lattice structure including a first portion separable from a second portion along a border, the border defined by at least some first elements of the lattice structure having a first strength and at least some second elements of the lattice structure having a second strength less than the first strength, wherein the second elements having the second strength comprise at least a segment defined by at least one of unfused build material and partially fused build material.

14. The method of claim 13, wherein additively manufacturing the 3D object comprises implementing the implement the border according to at least one of: a selectable proportion of the first elements and the second elements; and a selectable sequence of the respective first elements and second elements.

15. The method of claim 13, wherein additively manufacturing the 3D object comprises: forming the border to cause selective separation of the first portion and the second portion to result in a releasably connectable relationship between the respective first and second portions of the lattice structure.