WO2021221601A1

WO2021221601A1 - Partial melting in additive manufacturing

Info

Publication number: WO2021221601A1
Application number: PCT/US2020/030066
Authority: WO
Inventors: Seongsik Chang
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2020-04-27
Filing date: 2020-04-27
Publication date: 2021-11-04

Abstract

A light source for use in additive manufacturing includes a first light modulating element, which includes a diode laser element to emit light and a grating light valve to selectively permit projection of the emitted light onto selectable voxel locations of a respective layer of a build material.

Description

PARTIAL MELTING IN ADDITIVE MANUFACTURING

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 using a variety of different materials, some of which may comprise metal.

Brief Description of the Drawings

[0002] FIG. 1 is a block diagram and an isometric view schematically representing an example device and/or example method to additively manufacture a 3D object.

[0003] FIG. 2 is a diagram including a side view schematically representing a light modulating unit including a laser diode and a grating light valve (GLV). [0004] FIGS. 3, 4A, and 4B are each a top view of an example two-dimensional array of light modulating units.

[0005] FIG. 5A is a block diagram schematically representing an example object formation engine.

[0006] FIG. 5B is a block diagram schematically representing an example control portion.

[0007] FIG. 5C is a block diagram schematically representing an example user interface.

[0008] FIG. 6 is a flow diagram schematically representing an example method of additively manufacturing a 3D object.

Detailed Description

[0009] 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.

[0010] At least some examples of the present disclosure provide for additively manufacturing a 3D object via partial melting of selectable voxel locations of deposited build material followed by oven sintering to complete solidification of the formed 3D object. In some examples, the partial melting may be implemented via light modulating units, which comprise a diode laser element and a grating light valve (GLV), including an array of valve elements, to project the light (emitted by the laser diode) onto the selectable voxel locations of the build material.

[0011] The diode laser element provides an economical source of light at high intensity while the grating light valve (GLV) provides light transmission selectivity in an arrangement capable of withstanding the high intensities of light for causing partial melting of powder build materials, such as but not limited to metal powder build materials. For instance, in some examples, causing a desired degree of partial melting of some metal powder build materials sufficient to cause neck-to-neck fusion (further described below) may involve a fluence light of about 30 Joules/cm², and intensities of about 1 kW/cm² to about 100 kW/cm², depending on the size and type of particles of build material. Accordingly, the grating light valve (GLV) can withstand such intensities, whereas some other types of light transmission selectivity devices (e.g. digital micro-mirror devices (DMD)) may not be able to withstand such high intensities of light.

[0012] Moreover, the example diode laser element 205 and grating light valves (GLV) 207 can provide such intensities (to achieve the desired partial melting) at a cost substantially lower than using other expensive, high power light sources which are typically used to create complete melting, for example, in selective laser melting (SLM) method. In some examples, the substantially lower cost comprises a cost of at least one order of magnitude lower.

[0013] In some examples, completion of the solidification of the 3D object may be implemented via oven sintering which increases densification and which may relax stresses induced during the partial melting.

[0014] These examples, and additional examples, are described below in association with at least FIGS. 1-6.

[0015] FIG. 1 is a diagram 101 schematically representing an example device 100 (and/or example method) to additively manufacture a 3D object 180. As shown in FIG. 1 , in some examples, the device 100 comprises a material distributor 150 and a light source 200. In some examples, the light source 200 may sometimes be referred to as a radiation source. The material distributor 150 is arranged to dispense a build material layer-by-layer onto a build platform 142 to additively form the 3D object 180. Once formed, the 3D object 180 may be separated from the build platform 142. It will be understood that a 3D object of any shape and any size can be manufactured, and the cube-shaped object 180 depicted in FIG. 1 provides just one example shape and size of a 3D object. In some instances device 100 may sometimes be referred to as a 3D printer. The build platform 142 may sometimes be referred to as a build pad, print bed, or a receiving surface.

[0016] It will be understood that a finally formed 3D object 180 may comprise just selectable portions of a total amount of material initially distributed onto the build platform 142, with the selectable portions corresponding to deposited build material which has been fused, solidified, etc. to form the 3D object, and the remaining non-fused material being separated and discarded.

[0017] The material distributor 150 may be implemented via a variety of electromechanical or mechanical mechanisms, such as doctor blades, rollers, 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 platform 142 or relative to a previously deposited layer of build material. [0018] In some examples, the material distributor 150 has a length (L1) at least generally matching an entire length (L1) of the build platform 142, such that the material distributor 150 is capable of coating the entire build platform 142 with a layer 182 of build material in a single pass as the material distributor 150 travels the width (W1) of the build platform 142. In some examples, the material distributor 150 can selectively deposit layers of material in lengths and patterns less than a full length of the material distributor 150. In some examples, the material distributor 150 may coat the build platform 142 with a layer 182 of build material(s) using multiple passes instead of a single pass.

[0019] It will be further understood that a 3D object additively formed via device 100 may have a width and/or a length less than a width (W1) and/or length (L1) of the build platform 142.

[0020] In some examples, the material distributor 150 moves in a first orientation (represented by directional arrow F) while the light source 200 moves in a second orientation (represented by directional arrow S) generally perpendicular to the first orientation. In some examples, the material distributor 150 can deposit material in each pass of a back-and-forth travel path along the first orientation while the light source 200 can transmit light selectively 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 150, followed by a pass of the light source 200 before a second pass of the material distributor 150 is initiated, and so on. Further details regarding the light source 200 are provided below.

[0021] In some examples, the material distributor 150 and the light source unit 200 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 150 and the light source 200 may be supported and moved via a single carriage while in some such examples, the material distributor 150 and light source 200 may be supported and moved via separate, independent carriages. In some examples, the movement of the material distributor 150, light source 200, and/or their carriage(s) relative to the build platform 142 may sometimes be referred to as scanning. [0022] In some examples, the build material used to generally form the 3D object comprises a metal material, such as a metal powder. At least some example materials may comprise aluminum alloys, steel, titanium alloys, and the like. In some examples, the build material may comprise a ceramic material, while in some examples the build material may comprise a crystal material. Some such example materials may comprise quartz, alumina, glass, and the like.

[0023] In some examples, the build material may comprise a polymer material, and in some such examples, the polymer material comprises a polyamide material. However, in some examples, a broad range of polymer materials (or their combinations) may be employed as the build material. For instance, some example polymer materials may comprise nylon, thermoplastic materials, resin, carbon-fiber enhanced resin, polyetheretherketone (PEEK), and the like.

[0024] In some examples, whether a ceramic, crystal, metal, or polymer, the build material may take the form of a powder.

[0025] Regardless of the particular form, at least some examples of the build material are suitable for spreading, depositing, extruding, flowing, etc. in a form to produce layers (via material distributor 150) additively relative to build platform 142 and/or relative to previously formed first layers of the build material.

[0026] At least some aspects of the build materials will be described further below in association with at least some example intensities of light transmitted by the light source 200.

[0027] In some examples, the light source 200 comprises, and is to selectively transmit light via, an array of light modulating units 202 arranged in a side-by- side relationship (e.g. a linear array) as shown in FIG.1. In some examples, each respective light modulating unit 202 may sometimes be referred to as a radiation unit. As further shown in FIG. 1 , each light modulating unit 202 includes a diode laser element 205 and a grating light valve (GLV) 207. The diode laser element 205 emits light which selectively passes through grating light valve 207 to be projected onto a respective layer of build material on build platform 142. [0028] As further shown in the diagram 270 including the side view of FIG. 2, in one example implementation, each light modulating unit 202, the diode laser element 205 emits light E toward and into a grating light valve (GLV) 207. In some examples, each grating light valve (GLV) 207 comprises a linear array of valve elements 272, which are individually controllable to either dissipate light (e.g. to prevent its passage) or to permit passage and projection of light (as represented by arrows G) onto a respective layer of build material on the build platform 142. In particular, in some examples, each valve element 272 of the GLV 207 may comprise a ribbon structure which is configurable into a first state and a second state, and which operates on the principle of optical reflectance and optical interference. In the first state, the ribbon structure (defining the valve element 272) is configured to cause superposition of reflected radiation which constructively interferes such that light (e.g. radiation from the diode laser element 205) is permitted to pass through the respective valve element 272 onto a respective layer 182 of the build material. In some instances, in the first state the valve element 272 may sometimes be referred to as being “on”, an on pixel, or as a pixel in an “on” state. In the second state, the ribbon structure (defining the valve element 272) is configured to cause superposition of the reflected radiation to destructively interfere, such that the light (e.g. radiation from the diode laser element) is dissipated isotropically (e.g. at an 180 degree angle) and therefore not projected from the valve element. In some instances, in the second state the valve element 272 may sometimes be referred to as being “off”, an off pixel, or a pixel in an “off” state. Accordingly, via this arrangement each valve element 272 of a GLV 207 (and therefore of a light modulating unit 202) is individually controllable to modulate light to permit its projection or to prevent its projection on the build material.

[0029] In some examples, the grating light valve (GLV) 207 may comprise one example implementation of, or sometimes be referred to as, a spatial light modulator (SLM), which comprises an array of optical elements (e.g. 272) in which each optical element acts independently as an optical "valve" to modulate light intensity, such as in the above-described example implementation. [0030] In some examples, the diode laser element 205 comprises solely a diode laser (i.e. laser diode). However, in some examples, the diode laser element 205 may comprise a diode-pumped solid state (DPSS) laser, which includes a diode laser as part of its construction along with additional optical elements. Moreover, like the sole diode laser example, the example DPSS laser also provides a relatively inexpensive way to generate light, at desired intensity levels to cause partial melting and neck-to-neck fusion, as compared to much higher cost, high power laser sources typically used for selective laser sintering (SLS), selective laser melting (SLM), and the like.

[0031] With further reference to both FIGS. 1-2, in some examples, the light modulating units 202 of light source 200 selectively transmit light 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, assuming an appropriate distance between the valve element 272 and the target surface (e.g. a top surface of a respective layer 182 of build material), an X-Y dimension of a voxel corresponds to the area of light projected onto the build material from each individually controllable valve element 272 of a respective grating light valve (GLV) 207. In some examples, one such voxel corresponds to a voxel location 174 illustrated in FIG. 1 , while in some examples, several such voxels correspond to one of the voxel locations 174 in FIG. 1.

[0032] As further shown in FIG. 1 , in some examples, an at least partially formed 3D object 180 on build platform 142 comprises at least first portion 171 and an exterior side surface 188. During formation of a desired number of layers 182 of the build material, the light source 200 is employed to transmit light at some selectable voxel locations 174 of at least some respective layers 182 to at least partially define at least the first portion 171 of the 3D object. It will be understood that a group 172 of selectable voxel locations 174, or multiple different groups 172 of selectable voxel locations 174 may be selected in any position, any size, any shape, and/or combination of shapes.

[0033] In some examples, the at least some selectable voxel locations 174 may correspond to an entire layer 182 of a 3D object or just a portion of a layer 182. In some examples, each selectable voxel location 174 corresponds to a single voxel.

[0034] In some examples, 182a voxel may correspond to an about 30 micron (X) by about 30 micron (Y) area in the x-y plane, and each valve element 272 of a grating light valve (GLV) 207 (e.g. FIG. 2) may correspond to a single voxel. With this in mind, in some examples light may be transmitted from light source 200 at a resolution of 1000 voxels per 30 micron (X) by 3 centimeter (Y) area in the X-Y plane (e.g. per each GLV 207). It will be understood that depending on the construction of the grating light valve (GLV) 207, the size of the voxel (in the X-Y dimension) may comprise other dimensions, such as 20 micrometers (X) by about 20 micrometers, about 25 micrometers (X) by about 25 micrometers (Y), 35 micrometers (X) by about 35 micrometers (Y), and the like.

[0035] In some examples, each grating light valve (GLV) 207 comprises a total light projection area of 30 micrometers by 3 centimeters, where the 3 centimeters extends in an orientation across a width (W1 in FIG. 1) of the build platform 142 (e.g. scanning area) and 30 micrometers extends along a length (L1) of the build platform (e.g. scanning area). Using this information, one can determine how many grating light valves (GLV) 207 should be arranged side-by- side in order to have an array of such grating light valves (GLV) 207 extend fully across the width (W1) of the build platform 142 (e.g. the scanning area). For example, to cover a width W1 of the build platform 142 of 30 centimeters, then an array of 10 grating light valves (GLV) 207 would be used assuming each grating light valve (GLV) 207 has the dimensions noted above (e.g. 30 micrometers by 3 centimeters).

[0036] It will be further understood that when considering the voxel solely in the X-Y plane as an area on which light is projected, it may sometimes be referred to as a pixel. However, because the projected light causes heat to penetrate below the surface of the build material, the heat (caused by light projected by each valve element 272 (e.g. ribbon structure) of a respective grating light valve (GLV) 207 will affect a volume of build material, which may then sometimes be referred to a voxel of build material. [0037] Accordingly, it will be understood that the height (H2) of a voxel (Z dimension) is selectable in some examples, and may depend (at least in part) on the depth of penetration of partial melting caused by the light projected from the respective valve elements 272 (of each GLV 207 of the respective light units 202), wherein the thickness of build material deposited via the material distributor 150 may be selected to correspond to the expected depth of penetration of partial melting. Accordingly, in some examples, the height (H2) of the voxel may correspond to a thickness of one layer (e.g. 182) of the build material as distributed by material distributor 150. In some examples, a voxel may have a height H2 (or thickness) of about 100 microns. In some examples, a height of the voxel may fall between about 80 microns and about 100 microns. However, in some examples, a height of a voxel (H2) may fall outside the range of about 80 to about 100 microns. FIG. 1 also illustrates that the finally formed 3D object 180, comprising multiple layers 182, as having a height H1.

[0038] With this in mind, upon application of light (e.g. irradiating) by light source 200 onto the deposited build materials, the build material is heated to result in partial melting at selectable voxel locations 174 of the build material. In some examples, the partial melting may cause neck-to-neck fusion, which refers to the shape and manner by which separate particles of build material become connected as a neck grows between two separate particles. This phenomenon may sometimes be referred to as necking, which corresponds to deformation, caused by partial melting, in which contacts points develop between adjacent particles (e.g. powder particles) with the contact points gradually growing and/or forming “necks” between the adjacent particles. In some such examples, the partial melting and/or neck-to-neck fusion may be implemented without any substantial increase in densification of the particles of the build material.

[0039] In some examples, the light source 200 may control the projection of light (e.g. radiation) from each respective valve element 272 (of a respective GLV 207 of a respective light modulating unit 202) onto the build material (e.g. for a particular layer of build material), with a resulting degree of heating of the build material depending on an exposure time and intensity of the light on the selectable voxel locations (174 in FIG. 1). In some such examples, a pulse shape of the emitted light also may affect the degree of partial melting exhibited as neck-to-neck fusion. In some such examples, such as during relative movement between light source 200 and the build platform 142, exposure time and intensity may depend on, and/or be implemented in association with speed and/or direction of the relative movement. However, in other instances such as the later described two-dimensional array of light modulating units in FIG. 4A, the exposure time and/or intensity of transmitted light will not depend speed and/or direction of movement because the two-dimensional array is static and is sized and shaped to cover entire build platform (or at least size/shape of 3D object to be formed).

[0040] In some examples, the exposure time and/or intensity of light projected onto the selectable voxel locations (e.g. 174 in FIG. 1) also may be selected in accordance with the particular size and/or type of build material. For instance, in some examples the light projected via a valve element (e.g. 272 in FIG. 2) of a grating light valve (GLV) 207 may comprise an intensity of about 1 kW/cm² to about 100 kW/cm² for a particle size of about 30 to about 50 micrometers, such as some commercially available metal powders with about half of the light being absorbed by the powder. In some examples, the intensity range may comprise about 5 kW/cm² to about 70 kW/cm², while in some examples, the intensity range may comprise about 10 kW/cm² to about 50 kW/cm².

[0041] In some examples, the light projected via a valve element (e.g. 272) of a grating light valve (e.g. GLV 207 in FIGS. 1-2) may comprise an intensity of about 1 kW/cm² to about 10 kW/cm² for a particle size (of build material) about 10-15 micrometers, such as some commercially available particles, which may comprise a metal material. For the appropriately sized particles, these intensities may cause a desired degree of partial melting upon projection of light onto the selectable voxel locations 174 of the build material. Moreover, the example diode laser element 205 and grating light valve (GLV) 207 can provide such intensities at a cost substantially lower (e.g. at least one order of magnitude lower) than other more expensive, high power lasers. Furthermore, some commercially available light-transmission selectivity devices, such as digital micro-mirror devices (DMD), are not capable of withstanding such intensities to be used as in the examples of the present disclosure to cause photonic fusion of some build materials, such as but not limited to metal powders.

[0042] In some examples, causing a desired degree of partial melting of some ceramic or crystal materials sufficient to cause neck-to-neck fusion, while accounting for absorbency may comprise a fluence and intensities substantially the same as those described above for metals.

[0043] In some examples, causing a desired degree of partial melting of some polymer powder build materials sufficient to cause neck-to-neck fusion may comprise a fluence on the order of about 0.1 to about 10 Joules/cm², and intensities of about 0.01 kW/cm² to about 10 kW/cm², depending on the size and type of particles of build material.

[0044] It will be understood that a determination of numerical ranges regarding fluence and/or light intensities involve factors such as wavelength, light absorptivity, heat loss, and the like.

[0045] In some examples, assuming that the example light source 200 (via the respective valve elements 272 of the GLVs 207 of the respective light modulating units 202) projects a targeted intensity of light onto a selectable voxel location as described above, it may take about 1 millisecond of exposure time to cause the desired partial melting for a given selectable voxel location. However, it will be understood that other exposure times greater than or less than 1 milliseconds are contemplated, depending on the type of build material, fluence, etc.

[0046] After application of the radiation from light source 200 to selectable voxel locations 174, a respective layer 182 of build material is formed and additional layers 182 of build material may be formed in a similar manner as represented in FIG. 1.

[0047] Upon formation of all the desired layers 182 of the 3D object 180 via use of material distributor 150 and light source 200, the fully formed 3D object 180 may sometimes be referred to as a brown part to the extent that the formed 3D object omits binders and comprises neck-to-neck fusion. In addition, upon formation of all the desired layers 182 of the 3D object 180, the powder build material may exhibit about 60 percent to about 70 percent densification via the packing of the powder particles.

[0048] As represented by directional arrow B, the entire 3D object 180 is placed into an oven 250 (or other enclosable heating unit) for sintering. Oven sintering involves heating the 3D object at a temperature less than a melting temperature of the build material. In some examples, such as when the build material comprises a metal powder material, such sintering temperatures may range between about 900 degrees Celsius to about 1700 degrees Celsius.

[0049] Once the 3D object is received in the oven 250, further heating is applied in the form of sintering by which the already partially melted build material is further solidified to increase its densification to at least about 95 percent densification, in some examples. In some examples, the level of densification upon sintering may comprise at least about 96 percent, 97 percent, 98 percent, 99 percent. In some examples, as a result of sintering, the finally formed 3D object may exhibit volume shrinkage in all three dimensions (x, y, z).

[0050] Upon completing of sintering and cooling, the finally formed 3D object may be removed from the oven 250.

[0051] It will be further understood that the act of sintering in the oven generally relaxes stresses, which may have formed via the neck-to-neck fusion created from the partial melting due to the application of light from the light source 200. Via oven sintering, a more stable, robust structure for the 3D object may be obtained.

[0052] In some examples, the additive manufacturing device 100 forms a 3D object without the use of fusing agents, whether dry or liquid. In some examples, the additive manufacturing device 100 forms a 3D object without the use of binders.

[0053] It will be understood that in some examples in which the build material comprises polymer materials, the application of oven sintering may be omitted, and instead, the application of light via the light source 200 is performed in a manner to cause complete melting (e.g. 99% densification) of the polymer build material to fully form the 3D object. [0054] In some examples device 100 may comprise a control portion to direct operations of device 200, with one such example control portion being implemented via at least some of substantially the same features and attributes as control portion 500, as later described in association with at least FIG. 5B. In some such examples, operation via the control portion 500 also may comprise, and/or be implemented, via object formation engine 400 (FIG. 4A).

[0055] FIG. 3 is diagram schematically representing a top view of an example light source 320. As shown in FIG. 3, example light source 320 comprises a two-dimensional array 321 of light modulating units 202, which are arranged in rows 322. In some examples, each row 322 of light modulating units 202 in device 320 of FIG. 3 may comprise at least some of substantially the same features and attributes as the array 201 of light modulating units 202 in the light source 200 of FIG. 1. As such, each grating light valve (GLV) 207 shown in FIG. 3 comprises a linear array of valve elements (e.g. 272 in FIG. 2). Moreover, it will be understood that, the diode laser elements (e.g. 205 in FIGS. 1-2), of the light modulating units 202, which emit light to the grating light valves (GLV) 207, are omitted from FIG. 3 for illustrative clarity. In some examples, the light source 320 can take the place of the light source 200 in the device 100 of FIG. 1.

[0056] As further shown in FIG. 4, the two-dimensional array 321 has a width (W2) and a length (L2). In some examples, the width (W2) and length (L2) of array 321 correspond to a width (W1) and a length (L1) of the build platform 142 such that the light source 320 may be moved into a stationary position over the build platform 142 and transmit light onto a particular layer 182 of build material, without movement of the array 321 , at any selectable voxel location (e.g. 174 in FIG. 1) over the layer 182 of build material to cause partial melting of those selectable voxel locations 174.

[0057] In some examples, the width (W2) and length (L2) of array 321 of light modulating units 322 is less than a width (W1) and a length (L1) of the build platform 142.

[0058] In some examples involving the two-dimensional array 321 of FIG. 3, prior to applying light to cause partial melting of the build material, the build area is divided into multiple target portions. The light source 320 is then operated to cause just one (or a selectable number) of light modulating units 202 (which overlies a corresponding target portion of the build area) to project light (via individually controllable valve elements 272) onto the target portion of the build area. In some examples, the targeted portion may be implemented as selectable voxel locations 174 of a respective layer of build material. This process is repeated until light has been projected upon the voxel locations 174 in all of the target portions defining the build area for a particular 3D object.

[0059] FIG. 4A is a diagram including a top view of an example light source 350, which forms a two-dimensional array 351 of two rows 352A, 352B of light modulating units 202 (like elements 202 in FIG. 1). Similar to the view in FIG. 3, FIG. 4A omits the diode laser elements 205 (of each light modulating unit 202) for illustrative simplicity. In some examples, the light source 350 can take the place of the light source 200 in the device 100 of FIG. 1. In such an arrangement, the light source 350 can be moved over the build platform 132 in a first direction (arrow P1 in FIG. 4A) such that a first row 352A of light modulating units 202 passes over a respective layer 182 of build material immediately prior to the second row 352B of light modulating units 202 passing over the same respective layer 182 of build material. As the first row 352A of light modulating elements 202 passes over the respective layer 182 of build material, all of the individually controllable valve elements (e.g. 272 in FIG. 2) of each respective grating light valve (GLV) 207 are selected to project light, as represented by cross-hatching in FIG. 4A. This light is projected at an intensity to uniformly pre-heat the all of the selectable voxel locations 174 (underneath row 352A) of the respective layer 182 of build material. Thereafter, the immediately following second row 352B of light modulating units 202 selectively projects light onto just the selectable voxel locations (e.g. 174 in FIG. 1) of the uniformly pre-heated voxel locations at which is it desired to cause partial melting. Because of the pre-heating via the first row 352B, a lower amount of light can be projected (e.g. transmitted) via the second row 352B while still achieving a targeted degree of partial melting of the build material. This arrangement of the dual rows 352A, 352B may lower the power requirements and amount of light to be transmitted by the diode laser elements 205 and/or may enable faster completion of the partial melting of the build material (at selectable voxel locations 174).

[0060] In a system in which bi-directional use of the light source 350 can be employed, the diagram of FIG. 4B schematically depicts movement of the light source 350 in an opposite direction (as represented by directional array P2) in which the respective rows 352A, 352B (of light modulating units 202) reverse their roles. In this arrangement, row 352B transmits light in a uniform manner with all light modulating units 202 (including all their respective valve elements 272) being turned “on”, i.e. to project light so as to uniformly pre-heat the build material over which row 352B passes. Then, row 352A (of light modulating units 202) then selectively projects (e.g. transmits) light onto the selectable locations 174 at which partial melting is desired as part of forming the desired 3D object. As previously mentioned, this arrangement may lower the power requirements of a light source (e.g. diode laser element 205) used to generate and emit the light and also may enable faster completion of the partial melting of the build material (at selectable voxel locations 174).

[0061] FIG. 5A is a block diagram schematically representing an example object formation engine 400. In some examples, the object formation engine 400 may form part of a control portion 500, as later described in association with at least FIG. 5B, such as but not limited to comprising at least part of the instructions 511. In some examples, the object formation engine 400 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. 1-4B and/or as later described in association with FIGS. 5B-6. In some examples, the object formation engine 400 (FIG. 5A) and/or control portion 500 (FIG. 5B) may form part of, and/or be in communication with, an object formation device, such as the additive manufacturing device 100 in FIG. 1. Accordingly, in some examples, at least some aspects of control portion 500 may comprise one example implementation of a control portion of example device 100 in FIG. 1 and/or the associated example implementations in FIGS. 2- 4B. [0062] As shown in FIG. 5A, in some examples the object formation engine 400 may comprise a material distributor engine 402, a light modulating engine 406, and a sintering engine 408.

[0063] In some examples the material distributor engine 402 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 -4B and/or as later described in association with FIGS. 5B-6. Accordingly, in some examples the material distributor engine 402 may track and/or control distribution of layers of build material relative to a build platform (e.g. 142 in FIG. 1) and/or relative to previously deposited layers of build material. In some examples, the material distributor engine 402 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, via the material distributor engine 402, these materials are deposited via build material distributor 150 of device 100 (FIG. 1). It will be understood that such control by the material distributor engine 402 may comprise associated or cooperative control of a carriage supporting and providing movement of the material distributor 150.

[0064] In some examples, the material controlled via the material distributor engine 402 may comprise metals, 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. 1.

[0065] In some examples, the light modulating engine 406 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. 1-4B and/or as later described in association with FIGS. 5B-6. In some examples, the light modulating engine 406 of object formation engine 400 is to control operations of at least one light source (e.g. 200 in FIG. 1), such as but not limited to the manner as previously described in association with FIGS. 1- 4B. At least some parameters controllable via light modulating engine 406 comprise selecting a timing, intensity, exposure time, etc. of the light emitted from a diode laser element (e.g. 205 in FIG. 1) and/or controlling a timing, duration, sequence, pattern, etc. of opening and closing of the individually controllable valve elements (e.g. 272 in FIG. 2) of the grating light valves (GLV) 207. It will be understood that such control by the light modulating engine 406 may comprise associated or cooperative control of a carriage supporting and providing movement of the light modulating unit(s).

[0066] In some examples, the sintering engine 408 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. 1-4B and/or as later described in association with FIGS. 5B-6. In some examples, the sintering engine 408 is to track and/or control operation of sintering oven (e.g. 250 in FIG. 1), including initiation, management, and/or termination of the sintering process, which may comprise control to select and maintain the oven temperature at temperature less than a melting temperature of the build material.

[0067] As shown in FIG. 5A, in some examples, the object formation engine 400 comprises a location parameter 430, a volume parameter 432, and/or a shape parameter 434. In some examples, these parameters are to track and/or control a location (430), a volume (432), and/or a shape (434) of the partial melting and/sintering of the selectable voxel locations (e.g. 174 in FIG. 1), and thereby track and/or control a location, volume, and/or shape of the 3D object being additively formed.

[0068] In some examples, the object formation engine 400 may comprise a preheating parameter 450 which is to track and/or control preheating the build material prior to further selective heating at selectable voxel locations, such as described in association with at least FIGS. 4A-4B. In some examples, the preheating parameter 450 also may be implemented in association with preheating build material via heating the build platform 142 (FIG. 1).

[0069] It will be understood that various functions and parameters of object formation engine 400 may be operated interdependently and/or in coordination with each other, in at least some examples. [0070] FIG. 5B is a block diagram schematically representing an example control portion 500. In some examples, control portion 500 provides one example implementation of a control portion forming a part of, implementing, and/or generally managing the example additive manufacturing devices, as well as the particular portions, components, material distributors, light sources, light modulating units, sintering ovens, control portion, instructions, engines, functions, parameters, and/or methods, as described throughout examples of the present disclosure in association with FIGS. 1-5A and 5C-6. In some examples, control portion 500 includes a controller 502 and a memory 510. In general terms, controller 502 of control portion 500 comprises at least one processor 504 and associated memories. The controller 502 is electrically couplable to, and in communication with, memory 510 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, light sources, light modulating units, sintering ovens, 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 511 stored in memory 510 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 502 or control portion 500 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 511 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 400 in FIG. 5A.

[0071] In response to or based upon commands received via a user interface (e.g. user interface 520 in FIG. 5C) and/or via machine readable instructions, controller 502 generates control signals as described above in accordance with at least some of the examples of the present disclosure. In some examples, controller 502 is embodied in a general purpose computing device while in some examples, controller 502 is incorporated into or associated with at least some of the additive manufacturing devices, as well as the particular portions, components, material distributors, light sources, light modulating units, sintering ovens, control portion, instructions, engines, functions, parameters, and/or methods, etc. as described throughout examples of the present disclosure.

[0072] For purposes of this application, in reference to the controller 502, 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 510 of control portion 500 cause the processor to perform the above-identified actions, such as operating controller 502 to implement the formation of 3D objects via the various example implementations 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 510. The machine readable instructions may include a sequence of instructions, a processor- executable machine learning model, or the like. In some examples, memory 510 comprises a computer readable tangible medium providing non-volatile storage of the machine readable instructions executable by a process of controller 502. 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 502 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 502 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 502.

[0073] In some examples, control portion 500 may be entirely implemented within or by a stand-alone device.

[0074] In some examples, the control portion 500 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 500 may be implemented via a server accessible via the cloud and/or other network pathways. In some examples, the control portion 500 may be distributed or apportioned among multiple devices or resources such as among a server, an object formation device, and/or a user interface. [0075] In some examples, control portion 500 includes, and/or is in communication with, a user interface 520 as shown in FIG. 5C. In some examples, user interface 520 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, light sources, light modulating units, sintering ovens, control portion, instructions, engines, functions, parameters, and/or methods, etc., as described in association with FIGS. 1-5B and 6. In some examples, at least some portions or aspects of the user interface 520 are provided via a graphical user interface (GUI), and may comprise a display 524 and input 522.

[0076] FIG. 6 is a flow diagram of an example method 600. In some examples, method 600 may be performed via at least some of the devices, components, material distributors, light sources, light modulating units, sintering ovens, instructions, control portions, engines, functions, parameters, and/or methods, etc. as previously described in association with at least FIGS. 1-5C. In some examples, method 600 may be performed via at least some of the devices, components, material distributors, light sources, light modulating units, sintering ovens, instructions, control portions, engines, functions, parameters, and/or methods, etc. other than those previously described in association with at least FIGS. 1-5C.

[0077] As shown at 612 in FIG. 6, in some examples method 600 comprises providing a light source comprising an array of light modulating units arranged in a side-by-side relationship, with each light modulating unit comprising a diode laser element to emit light and a grating light valve, including an array of valve elements, to selectively permit transmission of the emitted light. As further shown at 614 in FIG. 6, in some examples method 600 comprises distributing a build material, layer-by-layer, on the build platform. As previously noted, in some examples, the build material may comprise a powder material, which in some examples, comprises at least one of a metal material, a ceramic material, or a crystal material. As further shown at 616 in FIG. 6, method 600 may further comprise selectively modulating light via the respective valve elements of the respective light modulating units onto selectable voxel locations of a respective layer of the build material to cause partial melting at the selectable voxel locations of the build material to at least partially form a 3D object. As further shown at 618 in FIG. 6, in some examples method 600 comprises sintering in an enclosable heating unit, the entire at least partially formed 3D object 3D object to solidify the selectable voxel locations of the build material to complete formation of the 3D object.

[0078] 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. An assembly comprising: a first device including: a build platform; a material distributor to distribute a metal powder build material, layer-by-layer, on the build platform; and a radiation source to selectively radiate light onto selectable voxel locations of a respective layer of the build material to cause partial melting to at least partially form a 3D object, wherein the radiation source comprises an array of radiation units in a side-by-side relationship, with each radiation unit comprising a diode laser element to radiate the light and a grating light valve, including an array of valve elements, to modulate projection of the radiated light onto the selectable voxel locations; and an oven to receive, and to sinter, the partially melted build material at the selectable voxel locations throughout the 3D object.

2. The assembly of claim 1 , wherein the radiation source is to selectively radiate the light during relative movement between the radiation source and the build platform.

3. The assembly of claim 1 , wherein the radiation source is to cause, via the partial melting, neck-to-neck fusion of the build material at the selectable voxel locations.

4. The assembly of claim 3, wherein the oven is to cause, via the sintering, at least about 95 percent densification of the partially melted, build material.

5. The assembly of claim 1 , wherein each respective diode laser element is to radiate the light on the order of 100 Watts intensity to achieve between about 1 kW/cm² and about 100 kW/cm² intensity of the light for each voxel location at which partial melting is to occur.

6. The device of claim 1 , wherein the array of radiation units of the radiation source comprises a two-dimensional array of rows of radiation units arranged in a side-by-side relationship.

7. The device of claim 6, wherein the two-dimensional array of rows of radiation units comprises an area corresponding to an area of the build platform.

8. The device of claim 6, wherein the two-dimensional array comprises a first row of radiation units and a second row of radiation units, and wherein upon relative movement between the radiation source and the build platform, the first row of radiation units is to project light non-selectively onto the build material to pre-heat the build material and the second row of radiation units is to project light selectively onto the selectable voxel locations of the build material to cause the partial melting at the selectable voxel locations.

9. The device of claim 1 , comprising: a control portion to control: at least the material distributor and the radiation source to at least partially form the 3D object including causing the partially melting at the selectable voxel locations of respective layers of the build material; and the oven to sinter at least the partially melted build material at the selectable voxel locations.

10. A light source for pre-sintering, photonic fusion in additive manufacturing, comprising: a first light modulating unit comprising: a diode laser element to emit light; and a grating light valve, including an array of individually controllable valve elements, to selectively permit projection of the emitted light onto selectable voxel locations of a respective layer of a powder build material to cause, via partial melting, neck-to-neck fusion of the build material at the selectable voxel locations, wherein each respective laser diode element emits the light on the order of 100 Watts intensity of the light to project, via each respective grating light valve, about 0.01 kW/cm² to about 100 kW/cm² intensity of the light onto the selectable voxel locations.

11. The light source of claim 10, comprising: an array of light modulating units, including the first light modulating unit, arranged in a side-by-side relationship.

12. The light source of claim 10, wherein the light source forms part of a 3D printer, which comprises: a build platform; and a material distributor to distribute the powder build material, layer-by- layer, on the build platform to additively form the 3D object, wherein upon relative movement between the array and the build platform, the respective individually controllable valve elements of the respective light modulating units are to selectively project light onto the selectable locations of a respective layer of powder build material.

13. A method comprising: providing a light source comprising an array of light modulating units arranged in a side-by-side relationship, with each light modulating unit comprising a diode laser element to emit light and a grating light valve, including an array of individually controllable valve elements, to selectively permit projection of the emitted light; distributing a powder build material, layer-by-layer, on the build platform, wherein the power build material comprises at least one of a metal material, a ceramic material, and a crystal material; modulating light via the respective individually controllable valve elements of the respective light modulating units onto selectable voxel locations of a respective layer of the build material to cause partial melting at the selectable voxel locations of the build material to at least partially form a 3D object; and sintering in an enclosable heating unit, the entire at least partially formed 3D object 3D object to solidify the selectable voxel locations of the build material to complete formation of the 3D object.

14. The method of claim 13, comprising causing, during the modulating, relative movement between the light source and the build platform.

15. The method of claim 13, comprising: causing, via the sintering, at least about 95 percent densification of the build material at the selectable locations.